编写代码过程中，有一些功能是需要将一个对象的属性复制到另一个相同类对象或者属性名相同的对象中的，尤其是两个相同类的对象之间复制属性时，常常有一些情况需要考虑：复制的源对象中的某些属性为null值，这个时候我们希望复制的过程中这些为null的属性不覆盖到目标对象上。
复制对象属性的方法我们可以利用工具类来实现：commons-beanutils，添加maven依赖或者下载好jar包之后我们来看BeanUtils类中的方法列表：
image.png
copyProperties(Object,Object)方法就是将源对象属性复制到目标对象上，但是这个方法存在一个问题，它没有是否忽略null值得选项,这里贴出优化后的BeanUtils:
image.png
做法是在源码中添加一个重载方法，将这个参数添加进去，以下是具体步骤：
在自己工程中添加BeanUtils、BeanUtilsBean这两个类
image.png
BeanUtilsBean代码
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.beanutils;
import java.beans.IndexedPropertyDescriptor;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* <p>JavaBean property population methods.</p>
*
* <p>This class provides implementations for the utility methods in
* {@link BeanUtils}.
* Different instances can be used to isolate caches between classloaders
* and to vary the value converters registered.</p>
*
* @author Craig R. McClanahan
* @author Ralph Schaer
* @author Chris Audley
* @author Rey Fran�ois
* @author Gregor Ra�man
* @version $Revision: 1.16 $ $Date: 2004/02/28 13:18:33 $
* @see BeanUtils
* @since 1.7
*/
public class BeanUtilsBean {
// ------------------------------------------------------ Private Class Variables
/**
* Contains <code>BeanUtilsBean</code> instances indexed by context classloader.
*/
private static final ContextClassLoaderLocal
beansByClassLoader = new ContextClassLoaderLocal() {
// Creates the default instance used when the context classloader is unavailable
protected Object initialValue() {
return new BeanUtilsBean();
}
};
/**
* Gets the instance which provides the functionality for {@link BeanUtils}.
* This is a pseudo-singleton - an single instance is provided per (thread) context classloader.
* This mechanism provides isolation for web apps deployed in the same container.
*/
public synchronized static BeanUtilsBean getInstance() {
return (BeanUtilsBean) beansByClassLoader.get();
}
/**
* Sets the instance which provides the functionality for {@link BeanUtils}.
* This is a pseudo-singleton - an single instance is provided per (thread) context classloader.
* This mechanism provides isolation for web apps deployed in the same container.
*/
public synchronized static void setInstance(BeanUtilsBean newInstance) {
beansByClassLoader.set(newInstance);
}
// --------------------------------------------------------- Attributes
/**
* Logging for this instance
*/
private Log log = LogFactory.getLog(BeanUtils.class);
/** Used to perform conversions between object types when setting properties */
private ConvertUtilsBean convertUtilsBean;
/** Used to access properties*/
private PropertyUtilsBean propertyUtilsBean;
// --------------------------------------------------------- Constuctors
/**
* <p>Constructs an instance using new property
* and conversion instances.</p>
*/
public BeanUtilsBean() {
this(new ConvertUtilsBean(), new PropertyUtilsBean());
}
/**
* <p>Constructs an instance using given property and conversion instances.</p>
*
* @param convertUtilsBean use this <code>ConvertUtilsBean</code>
* to perform conversions from one object to another
* @param propertyUtilsBean use this <code>PropertyUtilsBean</code>
* to access properties
*/
public BeanUtilsBean(
ConvertUtilsBean convertUtilsBean,
PropertyUtilsBean propertyUtilsBean) {
this.convertUtilsBean = convertUtilsBean;
this.propertyUtilsBean = propertyUtilsBean;
}
// --------------------------------------------------------- Public Methods
/**
* <p>Clone a bean based on the available property getters and setters,
* even if the bean class itself does not implement Cloneable.</p>
*
* <p>
* <strong>Note:</strong> this method creates a <strong>shallow</strong> clone.
* In other words, any objects referred to by the bean are shared with the clone
* rather than being cloned in turn.
* </p>
*
* @param bean Bean to be cloned
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InstantiationException if a new instance of the bean's
* class cannot be instantiated
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public Object cloneBean(Object bean)
throws IllegalAccessException, InstantiationException,
InvocationTargetException, NoSuchMethodException {
if (log.isDebugEnabled()) {
log.debug("Cloning bean: " + bean.getClass().getName());
}
Class clazz = bean.getClass();
Object newBean = null;
if (bean instanceof DynaBean) {
newBean = ((DynaBean) bean).getDynaClass().newInstance();
} else {
newBean = bean.getClass().newInstance();
}
getPropertyUtils().copyProperties(newBean, bean);
return (newBean);
}
/**
* <p>Copy property values from the origin bean to the destination bean
* for all cases where the property names are the same. For each
* property, a conversion is attempted as necessary. All combinations of
* standard JavaBeans and DynaBeans as origin and destination are
* supported. Properties that exist in the origin bean, but do not exist
* in the destination bean (or are read-only in the destination bean) are
* silently ignored.</p>
*
* <p>If the origin "bean" is actually a <code>Map</code>, it is assumed
* to contain String-valued <strong>simple</strong> property names as the keys, pointing at
* the corresponding property values that will be converted (if necessary)
* and set in the destination bean. <strong>Note</strong> that this method
* is intended to perform a "shallow copy" of the properties and so complex
* properties (for example, nested ones) will not be copied.</p>
*
* <p>This method differs from <code>populate()</code>, which
* was primarily designed for populating JavaBeans from the map of request
* parameters retrieved on an HTTP request, is that no scalar->indexed
* or indexed->scalar manipulations are performed. If the origin property
* is indexed, the destination property must be also.</p>
*
* <p>If you know that no type conversions are required, the
* <code>copyProperties()</code> method in {@link PropertyUtils} will
* execute faster than this method.</p>
*
* <p><strong>FIXME</strong> - Indexed and mapped properties that do not
* have getter and setter methods for the underlying array or Map are not
* copied by this method.</p>
*
* @param dest Destination bean whose properties are modified
* @param orig Origin bean whose properties are retrieved
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if the <code>dest</code> or
* <code>orig</code> argument is null
* @exception InvocationTargetException if the property accessor method
* throws an exception
*/
public void copyProperties(Object dest, Object orig)
throws IllegalAccessException, InvocationTargetException {
// Validate existence of the specified beans
if (dest == null) {
throw new IllegalArgumentException
("No destination bean specified");
}
if (orig == null) {
throw new IllegalArgumentException("No origin bean specified");
}
if (log.isDebugEnabled()) {
log.debug("BeanUtils.copyProperties(" + dest + ", " +
orig + ")");
}
// Copy the properties, converting as necessary
if (orig instanceof DynaBean) {
DynaProperty origDescriptors[] =
((DynaBean) orig).getDynaClass().getDynaProperties();
for (int i = 0; i < origDescriptors.length; i++) {
String name = origDescriptors[i].getName();
if (getPropertyUtils().isWriteable(dest, name)) {
Object value = ((DynaBean) orig).get(name);
copyProperty(dest, name, value);
}
}
} else if (orig instanceof Map) {
Iterator names = ((Map) orig).keySet().iterator();
while (names.hasNext()) {
String name = (String) names.next();
if (getPropertyUtils().isWriteable(dest, name)) {
Object value = ((Map) orig).get(name);
copyProperty(dest, name, value);
}
}
} else /* if (orig is a standard JavaBean) */ {
PropertyDescriptor origDescriptors[] =
getPropertyUtils().getPropertyDescriptors(orig);
for (int i = 0; i < origDescriptors.length; i++) {
String name = origDescriptors[i].getName();
if ("class".equals(name)) {
continue; // No point in trying to set an object's class
}
if (getPropertyUtils().isReadable(orig, name) &&
getPropertyUtils().isWriteable(dest, name)) {
try {
Object value =
getPropertyUtils().getSimpleProperty(orig, name);
copyProperty(dest, name, value);
} catch (NoSuchMethodException e) {
; // Should not happen
}
}
}
}
}
public void copyProperties(Object dest, Object orig,Boolean isnull)
throws IllegalAccessException, InvocationTargetException {
// Validate existence of the specified beans
if (dest == null) {
throw new IllegalArgumentException
("No destination bean specified");
}
if (orig == null) {
throw new IllegalArgumentException("No origin bean specified");
}
if (log.isDebugEnabled()) {
log.debug("BeanUtils.copyProperties(" + dest + ", " +
orig + ")");
}
// Copy the properties, converting as necessary
if (orig instanceof DynaBean) {
DynaProperty origDescriptors[] =
((DynaBean) orig).getDynaClass().getDynaProperties();
for (int i = 0; i < origDescriptors.length; i++) {
String name = origDescriptors[i].getName();
if (getPropertyUtils().isWriteable(dest, name)) {
Object value = ((DynaBean) orig).get(name);
copyProperty(dest, name, value);
}
}
} else if (orig instanceof Map) {
Iterator names = ((Map) orig).keySet().iterator();
while (names.hasNext()) {
String name = (String) names.next();
if (getPropertyUtils().isWriteable(dest, name)) {
Object value = ((Map) orig).get(name);
copyProperty(dest, name, value);
}
}
} else /* if (orig is a standard JavaBean) */ {
PropertyDescriptor origDescriptors[] =
getPropertyUtils().getPropertyDescriptors(orig);
for (int i = 0; i < origDescriptors.length; i++) {
String name = origDescriptors[i].getName();
if ("class".equals(name)) {
continue; // No point in trying to set an object's class
}
if (getPropertyUtils().isReadable(orig, name) &&
getPropertyUtils().isWriteable(dest, name)) {
try {
Object value =
getPropertyUtils().getSimpleProperty(orig, name);
if(isnull){
if(value!=null)
copyProperty(dest, name, value);
}else{
copyProperty(dest, name, value);
}
} catch (NoSuchMethodException e) {
; // Should not happen
}
}
}
}
}
/**
* <p>Copy the specified property value to the specified destination bean,
* performing any type conversion that is required. If the specified
* bean does not have a property of the specified name, or the property
* is read only on the destination bean, return without
* doing anything. If you have custom destination property types, register
* {@link Converter}s for them by calling the <code>register()</code>
* method of {@link ConvertUtils}.</p>
*
* <p><strong>IMPLEMENTATION RESTRICTIONS</strong>:</p>
* <ul>
* <li>Does not support destination properties that are indexed,
* but only an indexed setter (as opposed to an array setter)
* is available.</li>
* <li>Does not support destination properties that are mapped,
* but only a keyed setter (as opposed to a Map setter)
* is available.</li>
* <li>The desired property type of a mapped setter cannot be
* determined (since Maps support any data type), so no conversion
* will be performed.</li>
* </ul>
*
* @param bean Bean on which setting is to be performed
* @param name Property name (can be nested/indexed/mapped/combo)
* @param value Value to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
*/
public void copyProperty(Object bean, String name, Object value)
throws IllegalAccessException, InvocationTargetException {
// Trace logging (if enabled)
if (log.isTraceEnabled()) {
StringBuffer sb = new StringBuffer(" copyProperty(");
sb.append(bean);
sb.append(", ");
sb.append(name);
sb.append(", ");
if (value == null) {
sb.append("<NULL>");
} else if (value instanceof String) {
sb.append((String) value);
} else if (value instanceof String[]) {
String values[] = (String[]) value;
sb.append('[');
for (int i = 0; i < values.length; i++) {
if (i > 0) {
sb.append(',');
}
sb.append(values[i]);
}
sb.append(']');
} else {
sb.append(value.toString());
}
sb.append(')');
log.trace(sb.toString());
}
// Resolve any nested expression to get the actual target bean
Object target = bean;
int delim = name.lastIndexOf(PropertyUtils.NESTED_DELIM);
if (delim >= 0) {
try {
target =
getPropertyUtils().getProperty(bean, name.substring(0, delim));
} catch (NoSuchMethodException e) {
return; // Skip this property setter
}
name = name.substring(delim + 1);
if (log.isTraceEnabled()) {
log.trace(" Target bean = " + target);
log.trace(" Target name = " + name);
}
}
// Declare local variables we will require
String propName = null; // Simple name of target property
Class type = null; // Java type of target property
int index = -1; // Indexed subscript value (if any)
String key = null; // Mapped key value (if any)
// Calculate the target property name, index, and key values
propName = name;
int i = propName.indexOf(PropertyUtils.INDEXED_DELIM);
if (i >= 0) {
int k = propName.indexOf(PropertyUtils.INDEXED_DELIM2);
try {
index =
Integer.parseInt(propName.substring(i + 1, k));
} catch (NumberFormatException e) {
;
}
propName = propName.substring(0, i);
}
int j = propName.indexOf(PropertyUtils.MAPPED_DELIM);
if (j >= 0) {
int k = propName.indexOf(PropertyUtils.MAPPED_DELIM2);
try {
key = propName.substring(j + 1, k);
} catch (IndexOutOfBoundsException e) {
;
}
propName = propName.substring(0, j);
}
// Calculate the target property type
if (target instanceof DynaBean) {
DynaClass dynaClass = ((DynaBean) target).getDynaClass();
DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
if (dynaProperty == null) {
return; // Skip this property setter
}
type = dynaProperty.getType();
} else {
PropertyDescriptor descriptor = null;
try {
descriptor =
getPropertyUtils().getPropertyDescriptor(target, name);
if (descriptor == null) {
return; // Skip this property setter
}
} catch (NoSuchMethodException e) {
return; // Skip this property setter
}
type = descriptor.getPropertyType();
if (type == null) {
// Most likely an indexed setter on a POJB only
if (log.isTraceEnabled()) {
log.trace(" target type for property '" +
propName + "' is null, so skipping ths setter");
}
return;
}
}
if (log.isTraceEnabled()) {
log.trace(" target propName=" + propName + ", type=" +
type + ", index=" + index + ", key=" + key);
}
// Convert the specified value to the required type and store it
if (index >= 0) { // Destination must be indexed
Converter converter = getConvertUtils().lookup(type.getComponentType());
if (converter != null) {
log.trace(" USING CONVERTER " + converter);
value = converter.convert(type, value);
}
try {
getPropertyUtils().setIndexedProperty(target, propName,
index, value);
} catch (NoSuchMethodException e) {
throw new InvocationTargetException
(e, "Cannot set " + propName);
}
} else if (key != null) { // Destination must be mapped
// Maps do not know what the preferred data type is,
// so perform no conversions at all
// FIXME - should we create or support a TypedMap?
try {
getPropertyUtils().setMappedProperty(target, propName,
key, value);
} catch (NoSuchMethodException e) {
throw new InvocationTargetException
(e, "Cannot set " + propName);
}
} else { // Destination must be simple
Converter converter = getConvertUtils().lookup(type);
if (converter != null) {
log.trace(" USING CONVERTER " + converter);
value = converter.convert(type, value);
}
try {
getPropertyUtils().setSimpleProperty(target, propName, value);
} catch (NoSuchMethodException e) {
throw new InvocationTargetException
(e, "Cannot set " + propName);
}
}
}
/**
* <p>Return the entire set of properties for which the specified bean
* provides a read method. This map contains the to <code>String</code>
* converted property values for all properties for which a read method
* is provided (i.e. where the getReadMethod() returns non-null).</p>
*
* <p>This map can be fed back to a call to
* <code>BeanUtils.populate()</code> to reconsitute the same set of
* properties, modulo differences for read-only and write-only
* properties, but only if there are no indexed properties.</p>
*
* @param bean Bean whose properties are to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public Map describe(Object bean)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
if (bean == null) {
// return (Collections.EMPTY_MAP);
return (new java.util.HashMap());
}
if (log.isDebugEnabled()) {
log.debug("Describing bean: " + bean.getClass().getName());
}
Map description = new HashMap();
if (bean instanceof DynaBean) {
DynaProperty descriptors[] =
((DynaBean) bean).getDynaClass().getDynaProperties();
for (int i = 0; i < descriptors.length; i++) {
String name = descriptors[i].getName();
description.put(name, getProperty(bean, name));
}
} else {
PropertyDescriptor descriptors[] =
getPropertyUtils().getPropertyDescriptors(bean);
for (int i = 0; i < descriptors.length; i++) {
String name = descriptors[i].getName();
if (descriptors[i].getReadMethod() != null)
description.put(name, getProperty(bean, name));
}
}
return (description);
}
/**
* Return the value of the specified array property of the specified
* bean, as a String array.
*
* @param bean Bean whose property is to be extracted
* @param name Name of the property to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String[] getArrayProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getProperty(bean, name);
if (value == null) {
return (null);
} else if (value instanceof Collection) {
ArrayList values = new ArrayList();
Iterator items = ((Collection) value).iterator();
while (items.hasNext()) {
Object item = items.next();
if (item == null) {
values.add((String) null);
} else {
// convert to string using convert utils
values.add(getConvertUtils().convert(item));
}
}
return ((String[]) values.toArray(new String[values.size()]));
} else if (value.getClass().isArray()) {
int n = Array.getLength(value);
String results[] = new String[n];
for (int i = 0; i < n; i++) {
Object item = Array.get(value, i);
if (item == null) {
results[i] = null;
} else {
// convert to string using convert utils
results[i] = getConvertUtils().convert(item);
}
}
return (results);
} else {
String results[] = new String[1];
results[0] = value.toString();
return (results);
}
}
/**
* Return the value of the specified indexed property of the specified
* bean, as a String. The zero-relative index of the
* required value must be included (in square brackets) as a suffix to
* the property name, or <code>IllegalArgumentException</code> will be
* thrown.
*
* @param bean Bean whose property is to be extracted
* @param name <code>propertyname[index]</code> of the property value
* to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getIndexedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getIndexedProperty(bean, name);
return (getConvertUtils().convert(value));
}
/**
* Return the value of the specified indexed property of the specified
* bean, as a String. The index is specified as a method parameter and
* must *not* be included in the property name expression
*
* @param bean Bean whose property is to be extracted
* @param name Simple property name of the property value to be extracted
* @param index Index of the property value to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getIndexedProperty(Object bean,
String name, int index)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getIndexedProperty(bean, name, index);
return (getConvertUtils().convert(value));
}
/**
* Return the value of the specified indexed property of the specified
* bean, as a String. The String-valued key of the required value
* must be included (in parentheses) as a suffix to
* the property name, or <code>IllegalArgumentException</code> will be
* thrown.
*
* @param bean Bean whose property is to be extracted
* @param name <code>propertyname(index)</code> of the property value
* to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getMappedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getMappedProperty(bean, name);
return (getConvertUtils().convert(value));
}
/**
* Return the value of the specified mapped property of the specified
* bean, as a String. The key is specified as a method parameter and
* must *not* be included in the property name expression
*
* @param bean Bean whose property is to be extracted
* @param name Simple property name of the property value to be extracted
* @param key Lookup key of the property value to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getMappedProperty(Object bean,
String name, String key)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getMappedProperty(bean, name, key);
return (getConvertUtils().convert(value));
}
/**
* Return the value of the (possibly nested) property of the specified
* name, for the specified bean, as a String.
*
* @param bean Bean whose property is to be extracted
* @param name Possibly nested name of the property to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if a nested reference to a
* property returns null
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getNestedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getNestedProperty(bean, name);
return (getConvertUtils().convert(value));
}
/**
* Return the value of the specified property of the specified bean,
* no matter which property reference format is used, as a String.
*
* @param bean Bean whose property is to be extracted
* @param name Possibly indexed and/or nested name of the property
* to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return (getNestedProperty(bean, name));
}
/**
* Return the value of the specified simple property of the specified
* bean, converted to a String.
*
* @param bean Bean whose property is to be extracted
* @param name Name of the property to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* property cannot be found
*/
public String getSimpleProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
Object value = getPropertyUtils().getSimpleProperty(bean, name);
return (getConvertUtils().convert(value));
}
/**
* <p>Populate the JavaBeans properties of the specified bean, based on
* the specified name/value pairs. This method uses Java reflection APIs
* to identify corresponding "property setter" method names, and deals
* with setter arguments of type <code>String</code>, <code>boolean</code>,
* <code>int</code>, <code>long</code>, <code>float</code>, and
* <code>double</code>. In addition, array setters for these types (or the
* corresponding primitive types) can also be identified.</p>
*
* <p>The particular setter method to be called for each property is
* determined using the usual JavaBeans introspection mechanisms. Thus,
* you may identify custom setter methods using a BeanInfo class that is
* associated with the class of the bean itself. If no such BeanInfo
* class is available, the standard method name conversion ("set" plus
* the capitalized name of the property in question) is used.</p>
*
* <p><strong>NOTE</strong>: It is contrary to the JavaBeans Specification
* to have more than one setter method (with different argument
* signatures) for the same property.</p>
*
* <p><strong>WARNING</strong> - The logic of this method is customized
* for extracting String-based request parameters from an HTTP request.
* It is probably not what you want for general property copying with
* type conversion. For that purpose, check out the
* <code>copyProperties()</code> method instead.</p>
*
* @param bean JavaBean whose properties are being populated
* @param properties Map keyed by property name, with the
* corresponding (String or String[]) value(s) to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
*/
public void populate(Object bean, Map properties)
throws IllegalAccessException, InvocationTargetException {
// Do nothing unless both arguments have been specified
if ((bean == null) || (properties == null)) {
return;
}
if (log.isDebugEnabled()) {
log.debug("BeanUtils.populate(" + bean + ", " +
properties + ")");
}
// Loop through the property name/value pairs to be set
Iterator names = properties.keySet().iterator();
while (names.hasNext()) {
// Identify the property name and value(s) to be assigned
String name = (String) names.next();
if (name == null) {
continue;
}
Object value = properties.get(name);
// Perform the assignment for this property
setProperty(bean, name, value);
}
}
/**
* <p>Set the specified property value, performing type conversions as
* required to conform to the type of the destination property.</p>
*
* <p>If the property is read only then the method returns
* without throwing an exception.</p>
*
* <p>If <code>null</code> is passed into a property expecting a primitive value,
* then this will be converted as if it were a <code>null</code> string.</p>
*
* <p><strong>WARNING</strong> - The logic of this method is customized
* to meet the needs of <code>populate()</code>, and is probably not what
* you want for general property copying with type conversion. For that
* purpose, check out the <code>copyProperty()</code> method instead.</p>
*
* <p><strong>WARNING</strong> - PLEASE do not modify the behavior of this
* method without consulting with the Struts developer community. There
* are some subtleties to its functionality that are not documented in the
* Javadoc description above, yet are vital to the way that Struts utilizes
* this method.</p>
*
* @param bean Bean on which setting is to be performed
* @param name Property name (can be nested/indexed/mapped/combo)
* @param value Value to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
*/
public void setProperty(Object bean, String name, Object value)
throws IllegalAccessException, InvocationTargetException {
// Trace logging (if enabled)
if (log.isTraceEnabled()) {
StringBuffer sb = new StringBuffer(" setProperty(");
sb.append(bean);
sb.append(", ");
sb.append(name);
sb.append(", ");
if (value == null) {
sb.append("<NULL>");
} else if (value instanceof String) {
sb.append((String) value);
} else if (value instanceof String[]) {
String values[] = (String[]) value;
sb.append('[');
for (int i = 0; i < values.length; i++) {
if (i > 0) {
sb.append(',');
}
sb.append(values[i]);
}
sb.append(']');
} else {
sb.append(value.toString());
}
sb.append(')');
log.trace(sb.toString());
}
// Resolve any nested expression to get the actual target bean
Object target = bean;
int delim = findLastNestedIndex(name);
if (delim >= 0) {
try {
target =
getPropertyUtils().getProperty(bean, name.substring(0, delim));
} catch (NoSuchMethodException e) {
return; // Skip this property setter
}
name = name.substring(delim + 1);
if (log.isTraceEnabled()) {
log.trace(" Target bean = " + target);
log.trace(" Target name = " + name);
}
}
// Declare local variables we will require
String propName = null; // Simple name of target property
Class type = null; // Java type of target property
int index = -1; // Indexed subscript value (if any)
String key = null; // Mapped key value (if any)
// Calculate the property name, index, and key values
propName = name;
int i = propName.indexOf(PropertyUtils.INDEXED_DELIM);
if (i >= 0) {
int k = propName.indexOf(PropertyUtils.INDEXED_DELIM2);
try {
index =
Integer.parseInt(propName.substring(i + 1, k));
} catch (NumberFormatException e) {
;
}
propName = propName.substring(0, i);
}
int j = propName.indexOf(PropertyUtils.MAPPED_DELIM);
if (j >= 0) {
int k = propName.indexOf(PropertyUtils.MAPPED_DELIM2);
try {
key = propName.substring(j + 1, k);
} catch (IndexOutOfBoundsException e) {
;
}
propName = propName.substring(0, j);
}
// Calculate the property type
if (target instanceof DynaBean) {
DynaClass dynaClass = ((DynaBean) target).getDynaClass();
DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
if (dynaProperty == null) {
return; // Skip this property setter
}
type = dynaProperty.getType();
} else {
PropertyDescriptor descriptor = null;
try {
descriptor =
getPropertyUtils().getPropertyDescriptor(target, name);
if (descriptor == null) {
return; // Skip this property setter
}
} catch (NoSuchMethodException e) {
return; // Skip this property setter
}
if (descriptor instanceof MappedPropertyDescriptor) {
if (((MappedPropertyDescriptor) descriptor).getMappedWriteMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = ((MappedPropertyDescriptor) descriptor).
getMappedPropertyType();
} else if (descriptor instanceof IndexedPropertyDescriptor) {
if (((IndexedPropertyDescriptor) descriptor).getIndexedWriteMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = ((IndexedPropertyDescriptor) descriptor).
getIndexedPropertyType();
} else {
if (descriptor.getWriteMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = descriptor.getPropertyType();
}
}
// Convert the specified value to the required type
Object newValue = null;
if (type.isArray() && (index < 0)) { // Scalar value into array
if (value == null) {
String values[] = new String[1];
values[0] = (String) value;
newValue = getConvertUtils().convert((String[]) values, type);
} else if (value instanceof String) {
String values[] = new String[1];
values[0] = (String) value;
newValue = getConvertUtils().convert((String[]) values, type);
} else if (value instanceof String[]) {
newValue = getConvertUtils().convert((String[]) value, type);
} else {
newValue = value;
}
} else if (type.isArray()) { // Indexed value into array
if (value instanceof String) {
newValue = getConvertUtils().convert((String) value,
type.getComponentType());
} else if (value instanceof String[]) {
newValue = getConvertUtils().convert(((String[]) value)[0],
type.getComponentType());
} else {
newValue = value;
}
} else { // Value into scalar
if ((value instanceof String) || (value == null)) {
newValue = getConvertUtils().convert((String) value, type);
} else if (value instanceof String[]) {
newValue = getConvertUtils().convert(((String[]) value)[0],
type);
} else if (getConvertUtils().lookup(value.getClass()) != null) {
newValue = getConvertUtils().convert(value.toString(), type);
} else {
newValue = value;
}
}
// Invoke the setter method
try {
if (index >= 0) {
getPropertyUtils().setIndexedProperty(target, propName,
index, newValue);
} else if (key != null) {
getPropertyUtils().setMappedProperty(target, propName,
key, newValue);
} else {
getPropertyUtils().setProperty(target, propName, newValue);
}
} catch (NoSuchMethodException e) {
throw new InvocationTargetException
(e, "Cannot set " + propName);
}
}
private int findLastNestedIndex(String expression)
{
// walk back from the end to the start
// and find the first index that
int bracketCount = 0;
for (int i = expression.length() - 1; i>=0 ; i--) {
char at = expression.charAt(i);
switch (at) {
case PropertyUtils.NESTED_DELIM:
if (bracketCount < 1) {
return i;
}
break;
case PropertyUtils.MAPPED_DELIM:
case PropertyUtils.INDEXED_DELIM:
// not bothered which
--bracketCount;
break;
case PropertyUtils.MAPPED_DELIM2:
case PropertyUtils.INDEXED_DELIM2:
// not bothered which
++bracketCount;
break;
}
}
// can't find any
return -1;
}
/**
* Gets the <code>ConvertUtilsBean</code> instance used to perform the conversions.
*/
public ConvertUtilsBean getConvertUtils() {
return convertUtilsBean;
}
/**
* Gets the <code>PropertyUtilsBean</code> instance used to access properties.
*/
public PropertyUtilsBean getPropertyUtils() {
return propertyUtilsBean;
}
}
BeanUtils代码
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.beanutils;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import org.apache.commons.collections.FastHashMap;
/**
* <p>Utility methods for populating JavaBeans properties via reflection.</p>
*
* <p>The implementations are provided by {@link BeanUtilsBean}.
* These static utility methods use the default instance.
* More sophisticated behaviour can be provided by using a <code>BeanUtilsBean</code> instance.</p>
*
* @author Craig R. McClanahan
* @author Ralph Schaer
* @author Chris Audley
* @author Rey Fran�ois
* @author Gregor Ra�man
* @version $Revision: 1.40 $ $Date: 2004/02/28 13:18:33 $
* @see BeanUtilsBean
*/
public class BeanUtils {
// ------------------------------------------------------ Private Variables
/**
* Dummy collection from the Commons Collections API, to force a
* ClassNotFoundException if commons-collections.jar is not present in the
* runtime classpath, and this class is the first one referenced.
* Otherwise, the ClassNotFoundException thrown by ConvertUtils or
* PropertyUtils can get masked.
*/
private static FastHashMap dummy = new FastHashMap();
/**
* The debugging detail level for this component.
* @deprecated BeanUtils now uses commons-logging for all log messages.
* Use your favorite logging tool to configure logging for
* this class.
*/
private static int debug = 0;
/**
* @deprecated BeanUtils now uses commons-logging for all log messages.
* Use your favorite logging tool to configure logging for
* this class.
*/
public static int getDebug() {
return (debug);
}
/**
* @deprecated BeanUtils now uses commons-logging for all log messages.
* Use your favorite logging tool to configure logging for
* this class.
*/
public static void setDebug(int newDebug) {
debug = newDebug;
}
// --------------------------------------------------------- Class Methods
/**
* <p>Clone a bean based on the available property getters and setters,
* even if the bean class itself does not implement Cloneable.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#cloneBean
*/
public static Object cloneBean(Object bean)
throws IllegalAccessException, InstantiationException,
InvocationTargetException, NoSuchMethodException {
return BeanUtilsBean.getInstance().cloneBean(bean);
}
/**
* <p>Copy property values from the origin bean to the destination bean
* for all cases where the property names are the same.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#copyProperties
*/
public static void copyProperties(Object dest, Object orig)
throws IllegalAccessException, InvocationTargetException {
BeanUtilsBean.getInstance().copyProperties(dest, orig);
}
/**
* object copy is null,so not copy
* @param dest
* @param orig
* @param isnull
*/
public static void copyProperties(Object dest, Object orig,Boolean isnull)
throws IllegalAccessException, InvocationTargetException {
BeanUtilsBean.getInstance().copyProperties(dest, orig,isnull);
}
/**
* <p>Copy the specified property value to the specified destination bean,
* performing any type conversion that is required.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#copyProperty
*/
public static void copyProperty(Object bean, String name, Object value)
throws IllegalAccessException, InvocationTargetException {
BeanUtilsBean.getInstance().copyProperty(bean, name, value);
}
/**
* <p>Return the entire set of properties for which the specified bean
* provides a read method.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#describe
*/
public static Map describe(Object bean)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().describe(bean);
}
/**
* <p>Return the value of the specified array property of the specified
* bean, as a String array.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getArrayProperty
*/
public static String[] getArrayProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getArrayProperty(bean, name);
}
/**
* <p>Return the value of the specified indexed property of the specified
* bean, as a String.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getIndexedProperty(Object, String)
*/
public static String getIndexedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getIndexedProperty(bean, name);
}
/**
* Return the value of the specified indexed property of the specified
* bean, as a String. The index is specified as a method parameter and
* must *not* be included in the property name expression
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getIndexedProperty(Object, String, int)
*/
public static String getIndexedProperty(Object bean,
String name, int index)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getIndexedProperty(bean, name, index);
}
/**
* </p>Return the value of the specified indexed property of the specified
* bean, as a String.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getMappedProperty(Object, String)
*/
public static String getMappedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getMappedProperty(bean, name);
}
/**
* </p>Return the value of the specified mapped property of the specified
* bean, as a String.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getMappedProperty(Object, String, String)
*/
public static String getMappedProperty(Object bean,
String name, String key)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getMappedProperty(bean, name, key);
}
/**
* <p>Return the value of the (possibly nested) property of the specified
* name, for the specified bean, as a String.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getNestedProperty
*/
public static String getNestedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getNestedProperty(bean, name);
}
/**
* <p>Return the value of the specified property of the specified bean,
* no matter which property reference format is used, as a String.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getProperty
*/
public static String getProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getProperty(bean, name);
}
/**
* <p>Return the value of the specified simple property of the specified
* bean, converted to a String.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#getSimpleProperty
*/
public static String getSimpleProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return BeanUtilsBean.getInstance().getSimpleProperty(bean, name);
}
/**
* <p>Populate the JavaBeans properties of the specified bean, based on
* the specified name/value pairs.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#populate
*/
public static void populate(Object bean, Map properties)
throws IllegalAccessException, InvocationTargetException {
BeanUtilsBean.getInstance().populate(bean, properties);
}
/**
* <p>Set the specified property value, performing type conversions as
* required to conform to the type of the destination property.</p>
*
* <p>For more details see <code>BeanUtilsBean</code>.</p>
*
* @see BeanUtilsBean#setProperty
*/
public static void setProperty(Object bean, String name, Object value)
throws IllegalAccessException, InvocationTargetException {
BeanUtilsBean.getInstance().setProperty(bean, name, value);
}
}
使用
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