说明
初次了解AOP就自己基于AspectJ实现了一个打印日志的功能，后来才发现Spring也有相关的接口，想用的话还是使用Spring提供的接口吧，我的这套代码还是有很多不足之处，比如对每个切点添加操作都要直接修改原来的代码，还是不够优雅。
简述
平常我们打印日志的时候需要在每一个地方使用logger打印，aop提供了一种面向切面的方式，不需要在每一个地方都写一行代码，而是通过配置切面在我们需要执行的函数前后获得切点，在切点处直接执行相应的方法。话不多说，让我们一起来使用吧。
使用简述
本次使用的项目是基于Spring MVC的web项目，项目必须依赖spring，同时本项目基于注解配置了aop，当然你也可以xml配置aop。
Maven配置
<dependencies>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
相关代码
AopConfiguration是核心，使用方式见ControllerAopConfigurationImpl文件
/**
* 控制切面的自定义操作，
* 使用方式如下（基于注解）：
* 1. 重写pointCut方法并定义切点
* 2. 重写对应方法方法进入执行内容
* 使用方式如下（基于xml）：
* 1. 继承该类
* 2. 配置切点
* 3. 配置wrap方法为对应的before、after等
*/
@SuppressWarnings("unused")
public abstract class AopConfiguration implements ILoggerInfoHandler, IAopConfiguration {
// 不发出警告的程序最大执行时间，单位ms
private long timeThreshold;
// 日志打印的标签
private String tag;
public AopConfiguration() {
timeThreshold = getTimeThreshold();
tag = getTag();
}
private Logger logger = LogManager.getLogger(LogManager.ROOT_LOGGER_NAME);
protected Gson gson = new Gson();
/**
* 需要重写并定义切点
*/
protected abstract void pointCutMethod();
@Data
private static class AopResult {
private String explain;
private String type;
private Integer totalSize;
private Integer totalLength;
private List<Object> subList;
}
/**
* 包裹before函数
*/
// @Before("pointCutMethod()")
public final void wrapBefore(JoinPoint joinPoint) {
String[] parameterNames = ((MethodSignature) joinPoint.getSignature()).getParameterNames();
Object[] args = joinPoint.getArgs();
doBefore(joinPoint, parameterNames, args);
}
/**
* 包裹afterReturn函数
*/
// @AfterReturning(value = "pointCutMethod()", returning = "returnValue")
public final Object wrapAfterReturn(JoinPoint joinPoint, Object returnValue) {
return doAfterReturn(joinPoint, returnValue);
}
/**
* 包裹afterThrow函数
*/
// @AfterThrowing(value = "pointCutMethod()", throwing = "exception")
public final void wrapAfterThrow(JoinPoint joinPoint, Exception exception) throws Exception {
doAfterThrow(joinPoint, exception);
}
/**
* 包裹around函数
* @return
*/
// @Around(value = "pointCutMethod() && @annotation(methodLog)", argNames = "joinPoint")
@Around(value = "pointCutMethod()", argNames = "joinPoint")
private Object wrapAround(ProceedingJoinPoint joinPoint) throws Throwable {
String[] parameterNames = ((MethodSignature) joinPoint.getSignature()).getParameterNames();
Object[] args = joinPoint.getArgs();
return doAround(joinPoint, parameterNames, args);
}
private void doBefore(JoinPoint joinPoint, String[] parameterNames, Object[] args) {
before(joinPoint, parameterNames, args);
String classAndMethodName = joinPoint.getSignature().toShortString();
String logContent = "before " + tag + " execute: " + classAndMethodName + "\t" +
gson.toJson(parameterNames) + " --> " + gson.toJson(args);
log(logContent);
}
private Object doAfterReturn(JoinPoint joinPoint, final Object returnValue) {
afterReturn(joinPoint, returnValue);
String classAndMethodName = joinPoint.getSignature().toShortString();
String logContent = "after " + tag + " execute: " + classAndMethodName + "\t"
+ "result --> " + gson.toJson(getResultToAopResult(returnValue));
log(logContent);
return returnValue;
}
private void doAfterThrow(JoinPoint joinPoint, Exception exception) throws Exception {
afterThrow(joinPoint, exception);
String classAndMethodName = joinPoint.getSignature().toShortString();
String logContent = "after " + tag + " execute: " + classAndMethodName + "\t"
+ "throw --> " + gson.toJson(exception.getMessage());
log(logContent);
throw exception;
}
private Object doAround(ProceedingJoinPoint joinPoint, String[] parameterNames, Object[] args) throws Throwable {
String classAndMethodName = joinPoint.getSignature().toShortString();
Object returnValue = null;
// 执行切点
try {
doBefore(joinPoint, parameterNames, args);
long start = System.currentTimeMillis();
returnValue = joinPoint.proceed(args);
long duration = System.currentTimeMillis() - start;
if (duration > timeThreshold) {
warn( classAndMethodName + " execute time is too long: " + " --> " + duration + " ms");
} else {
log(classAndMethodName + " execute time: " + " --> " + duration + " ms");
}
doAfterReturn(joinPoint, returnValue);
} catch (Exception e) {
doAfterThrow(joinPoint, e);
afterThrow(joinPoint, e);
throw e;
}
return joinPoint.proceed(args);
}
/**
* 如果结果是非常长的list，就要截取一部分打印到日志
* @param resultValue
* @return
*/
@SuppressWarnings("unchecked")
protected Object getResultToAopResult(final Object resultValue) {
// 如果结果太长默认只取三条
final int maxSize = 3;
final int maxLength = 300;
AopResult aopResult = new AopResult();
if (resultValue instanceof Collection) {
Collection<Object> collection = (Collection<Object>) resultValue;
int length = gson.toJson(collection).length();
if (collection.size() > maxSize && length > maxLength) {
// 如果结果的长度大于maxSize，并且字符串长度大于maxLength
// 就取出其中的maxSize条数据打印在日志
aopResult.setType(resultValue.getClass().getSimpleName());
aopResult.setExplain("截取" + maxSize + "条结果展示！");
aopResult.setTotalSize(collection.size());
aopResult.setTotalLength(length);
aopResult.setSubList(Arrays.asList(collection.toArray()).subList(0, maxSize));
return aopResult;
}
}
return resultValue;
}
protected void log(String content) {
logger.info(content);
}
protected void warn(String content) {
logger.warn(content);
}
protected void error(String content) {
logger.error(content);
}
}
ControllerAopConfigurationImpl是一个打印日志的示例，您只需要修改@Pointcut里面的内容，如下文中的实例com.ninggc.template.springbootfastdemo.web.controller.*..*(..)是指controller包下的所有类的所有方法，将其修改为自己的包即可。
/**
* 控制controller的函数的入口和出口处打印日志
*/
@Component
@Aspect
public class ControllerAopConfigurationImpl extends AopConfiguration {
@Pointcut("execution(* com.ninggc.template.springbootfastdemo.web.controller.*..*(..))")
@Override
protected void pointCutMethod() { }
@Override
public String getTag() {
return "controller";
}
@Override
public void before(JoinPoint joinPoint, String[] parameterNames, Object[] args) {
}
@Override
public void afterReturn(JoinPoint joinPoint, Object returnValue) {
}
@Override
public void afterThrow(JoinPoint joinPoint, Exception exception) throws Exception {
}
}
其他的需要的文件
public interface IAopConfiguration {
void before(JoinPoint joinPoint, String[] parameterNames, Object[] args);
void afterReturn(JoinPoint joinPoint, final Object returnValue);
void afterThrow(JoinPoint joinPoint, Exception exception) throws Exception;
}
public interface ILoggerInfoHandler {
// 自定义输出日志的标签
String getTag();
// 自定义不发出警告的程序最大执行时间，单位ms，默认未300
default Long getTimeThreshold() {
return 500L;
}
}
以上四个文件是全部的文件，以下是具体的代码流程描述
AopConfiguration使用详述
//第一类方法 wrap*方法
wrapBefore
wrapAfterReturn
wrapAfterThrow
wrapAround
//以上四个wrap*的方法是相应的切点处执行的方法，在这个实例中只在wrapAround上注解了@around，没有涉及到其他三个方法
//第二类方法 do*方法
doBefore
doAfterReturn
doAfterThrow
doAround
//wrap*方法调用了do*方法，do*方法是我打印日志的格式，内部调用了更具体的方法，见第三类方法
//第三类方法，这是继承类可以改写的方法，方法功能如方法名所示
public interface IAopConfiguration {
void before(JoinPoint joinPoint, String[] parameterNames, Object[] args);
void afterReturn(JoinPoint joinPoint, final Object returnValue);
void afterThrow(JoinPoint joinPoint, Exception exception) throws Exception;
}
//打印日志的具体流程如下所示
private Object doAround(ProceedingJoinPoint joinPoint, String[] parameterNames, Object[] args) throws Throwable {
String classAndMethodName = joinPoint.getSignature().toShortString();
Object returnValue = null;
// 执行切点
try {
doBefore(joinPoint, parameterNames, args); //内部调用了before
long start = System.currentTimeMillis();
returnValue = joinPoint.proceed(args);
long duration = System.currentTimeMillis() - start;
if (duration > timeThreshold) {
warn( classAndMethodName + " execute time is too long: " + " --> " + duration + " ms");
} else {
log(classAndMethodName + " execute time: " + " --> " + duration + " ms");
}
doAfterReturn(joinPoint, returnValue); //内部调用了afterReturn
} catch (Exception e) {
doAfterThrow(joinPoint, e); //内部调用了afterThrow
throw e;
}
return joinPoint.proceed(args);
}
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