• SpringDataJPA 多对多的查询


     主要的结构目录:

    创建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;
    
        /**
         *配置多对多
         */
        @ManyToMany(targetEntity = User.class)//配置多表关系
        @JoinTable(name= "sys_user_role"
                //joinColumns,当前对象在中间表的外键
                ,joinColumns = {@JoinColumn(name = "sys_role_id",referencedColumnName = "role_id")}
                //inverseJoinColumns,对方对象在中间表的外键
                ,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)
         *       targetEntity:代表对方的实体类字节码
         *     2、配置中间表(包含两个外键)
         *       name:中间表的名称
         *       joinColumns,当前对象在中间表的外键
         *          name:外键名
         *          referencedColumnName:参照的主表的主键名
         *       inverseJoinColumns,对方对象在中间表的外键
         *          name:外键名
         *          referencedColumnName:
         */
        @ManyToMany(targetEntity = Role.class,cascade = CascadeType.ALL)
        @JoinTable(name= "sys_user_role"
                //joinColumns,当前对象在中间表的外键
                ,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<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.创建entityManagerFactory对象交给spring容器管理-->
        <bean id="entityManagerFactoty" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
            <property name="dataSource" ref="dataSource" />
            <!--配置的扫描的包(实体类所在的包) -->
            <property name="packagesToScan" value="cn.itcast.domain" />
            <!-- jpa的实现厂家 -->
            <property name="persistenceProvider">
                <bean class="org.hibernate.jpa.HibernatePersistenceProvider"/>
            </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="false" />
                    <!--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 -->
                    <property name="showSql" value="true" />
                </bean>
            </property>
    
            <!--jpa的方言 :高级的特性 -->
            <property name="jpaDialect" >
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
            </property>
    
            <!--注入jpa的配置信息
                加载jpa的基本配置信息和jpa实现方式(hibernate)的配置信息
                hibernate.hbm2ddl.auto : 自动创建数据库表
                    create : 每次都会重新创建数据库表
                    update:有表不会重新创建,没有表会重新创建表
            -->
            <property name="jpaProperties" >
                <props>
                    <prop key="hibernate.hbm2ddl.auto">update</prop>
                </props>
            </property>
    
        </bean>
    
        <!--2.创建数据库连接池 -->
        <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.配置事务管理器 -->
        <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.声明式事务 -->
    
        <!-- 6. 配置包扫描-->
        <context:component-scan base-package="cn.itcast" ></context:component-scan>
    </beans>
    

      

        保存一个用户,保存一个角色

        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程序员");
    
            user.getRoles().add(role);
    
            userDao.save(user);
            roleDao.save(role);
    
        }
    

      测试中

    //测试级联添加
        @Test
        @Transactional
        @Rollback(false)
        public  void  testCadeAdd(){
            User user = new User();
            user.setUserName("小李");
    
            Role role = new Role();
            role.setRoleName("java程序员");
    
            user.getRoles().add(role);
    
            userDao.save(user);
            //roleDao.save(role);
    
        }
    
        //测试级联删除
        @Test
        @Transactional
        @Rollback(false)
        public  void  testCadeRemove(){
            //查询1号用户
            User user = userDao.findOne(1l);
            //删除1号用户
            userDao.delete(user);
        }
    

      在测试中主要spring配置中的问题,主要是配置中不能出问题。在这些中主要调用的是接口中继承的两个类,所以前面也介绍了继承的两个类中的方法

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  • 原文地址:https://www.cnblogs.com/easyjie/p/12008350.html
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