spring data jpa 多对多查询

package com.ytkj.dao;

import com.ytkj.entity.Customer;
import com.ytkj.entity.Role;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * JpaRepository<实体类类型，主键类型>：用来完成基本CRUD操作
 * JpaSpecificationExecutor<实体类类型>：用于复杂查询（分页等查询操作）
 */
public interface RoleDao extends JpaRepository<Role,Long>, JpaSpecificationExecutor<Role> {


}

package com.ytkj.dao;

import com.ytkj.entity.Customer;
import com.ytkj.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * JpaRepository<实体类类型，主键类型>：用来完成基本CRUD操作
 * JpaSpecificationExecutor<实体类类型>：用于复杂查询（分页等查询操作）
 */
public interface UserDao extends JpaRepository<User,Long>, JpaSpecificationExecutor<User> {


}

　　

package com.ytkj.dao;

import com.ytkj.entity.Customer;
import com.ytkj.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * JpaRepository<实体类类型，主键类型>：用来完成基本CRUD操作
 * JpaSpecificationExecutor<实体类类型>：用于复杂查询（分页等查询操作）
 */
public interface UserDao extends JpaRepository<User,Long>, JpaSpecificationExecutor<User> {


}

　　

package com.ytkj.entity;

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;

    /**
     * 配置用户到角色的多对多关系
     *      配置多对多的映射关系
     *          1.声明表关系的配置
     *              @ManyToMany(targetEntity = Role.class)  //多对多
     *                  targetEntity：代表对方的实体类字节码
     *          2.配置中间表（包含两个外键）
     *                @JoinTable
     *                  name : 中间表的名称
     *                  joinColumns：配置当前对象在中间表的外键
     *                      @JoinColumn的数组
     *                          name：外键名
     *                          referencedColumnName：参照的主表的主键名
     *                  inverseJoinColumns：配置对方对象在中间表的外键
     */
    @ManyToMany(targetEntity = Role.class,cascade = CascadeType.ALL)
    @JoinTable(name = "sys_user_role",
            //joinColumns,当前对象在中间表中的外键
            joinColumns = {@JoinColumn(name = "sys_user_id",referencedColumnName = "user_id")},
            //inverseJoinColumns，对方对象在中间表的外键
            inverseJoinColumns = {@JoinColumn(name = "sys_role_id",referencedColumnName = "role_id")}
    )
    private Set<Role> roles = new HashSet<>();

    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;
    }
}

　　

import com.ytkj.dao.RoleDao;
import com.ytkj.dao.UserDao;
import com.ytkj.entity.Role;
import com.ytkj.entity.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.annotation.Rollback;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

/**
 * 多对多测试 保存/删除操作
 */
@RunWith(SpringJUnit4ClassRunner.class)//声明spring提供的单元测试环境
@ContextConfiguration(locations = "classpath:applicationContext.xml")//指定spring容器的配置信息
public class SpringdatajpaManyToManyTest {
    @Autowired
    private UserDao userDao;

    @Autowired
    private RoleDao roleDao;

    /**
     * 需求：
     * 	保存用户和角色
     * 要求：
     * 	创建2个用户和3个角色
     * 	让1号用户具有1号和2号角色(双向的)
     * 	让2号用户具有2号和3号角色(双向的)
     *  保存用户和角色
     * 问题：
     *  在保存时，会出现主键重复的错误，因为都是要往中间表中保存数据造成的。
     * 解决办法：
     * 	让任意一方放弃维护关联关系的权利
     */
    @Test
    @Transactional  //开启事务
    @Rollback(false)//设置为不回滚
    public void test(){
        //创建对象
        User u1 = new User();
        u1.setUserName("用户1");
        Role r1 = new Role();
        r1.setRoleName("角色1");
        //建立关联关系
        u1.getRoles().add(r1);
        r1.getUsers().add(u1);
        //保存
        roleDao.save(r1);
        userDao.save(u1);
    }

    /**
     * 删除操作
     * 	在多对多的删除时，双向级联删除根本不能配置
     * 禁用
     *	如果配了的话，如果数据之间有相互引用关系，可能会清空所有数据
     */
    @Test
    @Transactional
    @Rollback(false)//设置为不回滚
    public void testDelete() {
        userDao.delete(1l);
    }
}

　　

<?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" xmlns:task="http://www.springframework.org/schema/task"
       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的整合-->

    <!--1.创建entityManagerFactory对象交给spring管理-->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <!--数据库注入-->
        <property name="dataSource" ref="dataSource"/>
        <!--配置包的扫描-->
        <property name="packagesToScan" value="com.ytkj.entity"/>
        <!--jpa实现厂家-->
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider"></bean>
        </property>
        <!--JPA的供应商适配器-->
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <!--配置是否自动创建数据库表-->
                <property name="generateDdl" value="true" />
                <!--指定数据库类型-->
                <property name="database" value="MYSQL" />
                <!--数据库方言：支持的特有语法-->
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                <!--是否显示sql语句-->
                <property name="showSql" value="true" />
            </bean>
        </property>

        <!--jpa方言：高级特性-->
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>
    </bean>

    <!--2.创建数据连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!--数据库信息-->
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://192.168.2.101:3306/ytkj?serverTimeZone=UTC"/>
        <property name="user" value="root"/>
        <property name="password" value="123456"/>
    </bean>

    <!--3.整合spring-data-jpa-->
    <jpa:repositories base-package="com.ytkj.dao" transaction-manager-ref="transacManager" entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>

    <!--4.配置事务管理器-->
    <bean id="transacManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

    <!--5.声明式事务-->
    <tx:advice id="txAdvice" transaction-manager="transacManager">
        <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(* com.ytkj.service.*.*(..))" />
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
    </aop:config>

    <context:component-scan base-package="com.ytkj"/>

</beans>

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.ytkj</groupId>
    <artifactId>springdatajpa</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <spring.version>5.1.7.RELEASE</spring.version>
        <hibernate.version>5.0.7.Final</hibernate.version>
        <slf4j.version>1.6.6</slf4j.version>
        <log4j.version>1.2.12</log4j.version>
        <c3p0.version>0.9.1.2</c3p0.version>
        <mysql.version>5.1.6</mysql.version>
    </properties>
    <dependencies>



        <!-- junit单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.9</version>
            <scope>test</scope>
        </dependency>

        <!-- spring beg -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.6.8</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!--spring对orm框架支持-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- spring end -->

        <!-- hibernate beg -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>${hibernate.version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>${hibernate.version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>5.2.1.Final</version>
        </dependency>
        <!-- hibernate end -->

        <!-- c3p0 beg -->
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>${c3p0.version}</version>
        </dependency>
        <!-- c3p0 end -->

        <!-- log end -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- log end -->


        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>

        <!--sprngdatajpa依赖-->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>1.9.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>4.2.4.RELEASE</version>
        </dependency>

        <!-- el beg 使用spring data jpa 必须引入 -->
        <dependency>
            <groupId>javax.el</groupId>
            <artifactId>javax.el-api</artifactId>
            <version>2.2.4</version>
        </dependency>

        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>javax.el</artifactId>
            <version>2.2.4</version>
        </dependency>

        <!-- el end -->
    </dependencies>

</project>