hibernate详解（十四）组件映射

组件映射

• 组建映射是指在一个实体类中有一个属性为自定义的类，但是自定义的类中并没有oid，在数据库中也没有对应这个类的表。
  表结构：

/* 组件映射 */
CREATE TABLE t_customer(
    id NUMBER(10) PRIMARY KEY,
    name VARCHAR2(20),
    province VARCHAR2(20),
    city VARCHAR2(20),
    street VARCHAR2(20)
);

Customner类

package com.iotek.basic.component.pojo;

import java.io.Serializable;

public class Customer implements Serializable {

    private static final long serialVersionUID = 5660598920023039135L;
    private Long id;
    private String name;
    private Address address;
    
    public Customer() {}

    public Customer(Long id, String name, Address address) {
        super();
        this.id = id;
        this.name = name;
        this.address = address;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Customer [id=" + id + ", name=" + name + ", address=" + address + "]";
    }
    
    
}

组件类 Address.java

package com.iotek.basic.component.pojo;

import java.io.Serializable;

public class Address implements Serializable {

    private static final long serialVersionUID = 1921592338080264702L;
    private String province;
    private String city;
    private String street;
    private Customer customer;
    
    public Address() {}

    public Address(String province, String city, String street, Customer customer) {
        super();
        this.province = province;
        this.city = city;
        this.street = street;
        this.customer = customer;
    }

    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public Customer getCustomer() {
        return customer;
    }

    public void setCustomer(Customer customer) {
        this.customer = customer;
    }

    @Override
    public String toString() {
        return "Address [province=" + province + ", city=" + city + ", street=" + street + ", customer=" + customer
                + "]";
    }
    
    
}

映射文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.iotek.basic.component.pojo">
    <class name="Customer" table="T_CUSTOMER">
        <id name="id" column="ID" type="long">
            <generator class="sequence">
                <param name="sequence">t_customer_seq</param>
            </generator>
        </id>
        
        <property name="name" type="string" column="NAME"/>
        
        <component name="address" class="Address">
            <parent name="customer"/>
            <property name="province" />
            <property name="city" />
            <property name="street" />
        </component>
    </class>
</hibernate-mapping>

hibernate.cfg.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory>
        <!-- property 元素用于配置Hibernate中的属性 键:值 -->
        
          <!-- hibernate.connection.driver_class : 连接数据库的驱动  -->
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        
          <!-- hibernate.connection.url : 连接数据库的地址,路径 -->
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
        
          <!-- hibernate.connection.username : 连接数据库的用户名 -->
        <property name="connection.username">guest</property>
        
          <!-- hibernate.connection.password : 连接数据库的密码 -->
        <property name="connection.password">guest</property>
        
          <!-- show_sql: 操作数据库时,会 向控制台打印sql语句 -->
        <property name="show_sql">true</property>
        
          <!-- 数据库方言配置 org.hibernate.dialect.Oracle10gDialect (选择最短的)-->
        <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
        
        <!-- 配置连接池最大连接数-->
        <property name="hibernate.c3p0.max_size">20</property>
        
        <!-- 配置连接池最小连接数-->
        <property name="hibernate.c3p0.min_size">2</property>
        
        <!-- 配置连接池超时时间-->
        <property name="hibernate.c3p0.timeout">5000</property>
        
        <!-- 配置连接池最大数量-->!

        <property name="hibernate.c3p0.max_statements">100</property>
        
        <!-- 配置连接池空闲检索时间-->
        <property name="hibernate.c3p0.idle_test_period">150</property>
        
        <!-- 配置连接池自增数量-->
        <property name="hibernate.c3p0.acquire_increment">2</property>
        
        <!-- 配置连接池验证-->
        <property name="hibernate.c3p0.validate">false</property>
        
        <mapping resource="com/iotek/basic/pojo/Student.hbm.xml"/>
        <mapping resource="com/iotek/basic/inheritance/pojo/concrete.hbm.xml"/>
        <mapping resource="com/iotek/basic/component/pojo/Customer.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

看代码就可以理解了。
总结：

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