SpringDataJPA 多對多的查詢

 主要的結構目錄：

 

創建Role.java

 

 

package cn.itcast.domain;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "sys_role")
public class Role {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "role_id")
    private  Long roleId;
    @Column(name = "role_name")
    private  String roleName;

    /** *配置多對多 */ @ManyToMany(targetEntity = User.class)//配置多表關系 @JoinTable(name= "sys_user_role" //joinColumns,當前對象在中間表的外鍵 ,joinColumns = {@JoinColumn(name = "sys_role_id",referencedColumnName = "role_id")} //inverseJoinColumns，對方對象在中間表的外鍵 ,inverseJoinColumns = {@JoinColumn(name = "sys_user_id",referencedColumnName = "user_id")}) private Set<User> users=new HashSet<User>();

    public Long getRoleId() {
        return roleId;
    }

    public void setRoleId(Long roleId) {
        this.roleId = roleId;
    }

    public String getRoleName() {
        return roleName;
    }

    public void setRoleName(String roleName) {
        this.roleName = roleName;
    }

    public Set<User> getUsers() {
        return users;
    }

    public void setUsers(Set<User> users) {
        this.users = users;
    }
}

　　主要的User.java

package cn.itcast.domain;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "sys_user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "user_id")
    private  Long userId;
    @Column(name = "user_name")
    private String userName;
    @Column(name = "age")
    private Integer age;

    /** *配置用戶到角色的多對多關系 * 配置多對多的映射關系 * 1.聲明表關系的配置 * @ManyToMany(targetEntity = Role.class) * targetEntity:代表對方的實體類字節碼 * 2、配置中間表（包含兩個外鍵） * name：中間表的名稱 * joinColumns,當前對象在中間表的外鍵 * name：外鍵名 * referencedColumnName：參照的主表的主鍵名 * inverseJoinColumns，對方對象在中間表的外鍵 * name：外鍵名 * referencedColumnName： */ @ManyToMany(targetEntity = Role.class,cascade = CascadeType.ALL) @JoinTable(name= "sys_user_role" //joinColumns,當前對象在中間表的外鍵 ,joinColumns = {@JoinColumn(name = "sys_user_id",referencedColumnName = "user_id")} //inverseJoinColumns，對方對象在中間表的外鍵 ,inverseJoinColumns = {@JoinColumn(name = "sys_role_id",referencedColumnName = "role_id")}) private Set<Role> roles=new HashSet<Role>();

    public Long getUserId() {
        return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }
}

　　主要的RoleDao.java

public interface RoleDao extends JpaRepository<Role,Long>,JpaSpecificationExecutor<Role> {
}

　　主要的UserDao.java

public interface UserDao extends JpaRepository<User,Long>,JpaSpecificationExecutor<User> {
}

　　在配置applicationContext.xml中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa"
       xsi:schemaLocation="
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
		http://www.springframework.org/schema/data/jpa
		http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">

    <!--spring 和 spring data jpa的配置-->

    <!-- 1.創建entityManagerFactory對象交給spring容器管理-->
    <bean id="entityManagerFactoty" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!--配置的掃描的包（實體類所在的包） -->
        <property name="packagesToScan" value="cn.itcast.domain" />
        <!-- jpa的實現廠家 -->
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider"/>
        </property>

        <!--jpa的供應商適配器 -->
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <!--配置是否自動創建數據庫表 -->
                <property name="generateDdl" value="false" />
                <!--指定數據庫類型 -->
                <property name="database" value="MYSQL" />
                <!--數據庫方言：支持的特有語法 -->
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                <!--是否顯示sql -->
                <property name="showSql" value="true" />
            </bean>
        </property>

        <!--jpa的方言 ：高級的特性 -->
        <property name="jpaDialect" >
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>

        <!--注入jpa的配置信息 加載jpa的基本配置信息和jpa實現方式（hibernate）的配置信息 hibernate.hbm2ddl.auto : 自動創建數據庫表 create ： 每次都會重新創建數據庫表 update：有表不會重新創建，沒有表會重新創建表 --> <property name="jpaProperties" > <props> <prop key="hibernate.hbm2ddl.auto">update</prop> </props> </property>

    </bean>

    <!--2.創建數據庫連接池 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="root"></property>
        <property name="password" value="root"></property>
        <property name="jdbcUrl" value="jdbc:mysql:///jpa" ></property>
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
    </bean>

    <!--3.整合spring dataJpa-->
    <jpa:repositories base-package="cn.itcast.dao" transaction-manager-ref="transactionManager"
                   entity-manager-factory-ref="entityManagerFactoty" ></jpa:repositories>

    <!--4.配置事務管理器 -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactoty"></property>
    </bean>

    <!-- 4.txAdvice-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="save*" propagation="REQUIRED"/>
            <tx:method name="insert*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="get*" read-only="true"/>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>

    <!-- 5.aop-->
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* cn.itcast.service.*.*(..))" />
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
    </aop:config>


    <!--5.聲明式事務 -->

    <!-- 6. 配置包掃描-->
    <context:component-scan base-package="cn.itcast" ></context:component-scan>
</beans>

　　

    保存一個用戶，保存一個角色

    主要的applicationContext.xml中

     <property name="jpaProperties" >
            <props>
                <prop key="hibernate.hbm2ddl.auto">create</prop>
            </props>
        </property>

    @Test
    @Transactional
    @Rollback(false)
    public  void  testAdd(){
        User user = new User();
        user.setUserName("小李");

        Role role = new Role();
        role.setRoleName("java程序員");

        user.getRoles().add(role);

        userDao.save(user);
        roleDao.save(role);

    }

　　測試中

//測試級聯添加
    @Test
    @Transactional
    @Rollback(false)
    public  void  testCadeAdd(){
        User user = new User();
        user.setUserName("小李");

        Role role = new Role();
        role.setRoleName("java程序員");

        user.getRoles().add(role);

        userDao.save(user);
        //roleDao.save(role);

    }

    //測試級聯刪除
    @Test
    @Transactional
    @Rollback(false)
    public  void  testCadeRemove(){
        //查詢1號用戶
        User user = userDao.findOne(1l);
        //刪除1號用戶
        userDao.delete(user);
    }

　　在測試中主要spring配置中的問題，主要是配置中不能出問題。在這些中主要調用的是接口中繼承的兩個類，所以前面也介紹了繼承的兩個類中的方法