一、多表操作之多对多
创建many2many项目
创建maven项目，并添加依赖
<properties> <spring.version>5.0.2.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>8.0.19</mysql.version> </properties> <dependencies> <!-- junit单元测试 --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</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>${spring.version}</version> </dependency> <!-- spring对orm框架的支持包--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${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>${mysql.version}</version> </dependency> <!-- spring data jpa 的坐标--> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-jpa</artifactId> <version>1.9.0.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</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>
在resource目录下新增applicationContext.xml，新增以下内容
<?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的配置--> <!-- 配置包扫描--> <context:component-scan base-package="com.citi" ></context:component-scan> <!-- 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="com.citi.entity" /> <!-- 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 记载jpa的基本配置信息和jpa实现方式的配置信息--> <property name="jpaProperties"> <props> <prop key="hibernate.hbm2ddl.auto">create</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="Abc*123456"></property> <property name="jdbcUrl" value="jdbc:mysql://rm-uf67r962043910k193o.mysql.rds.aliyuncs.com:3306/test?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false&serverTimezone=Asia/Shanghai" ></property> <property name="driverClass" value="com.mysql.cj.jdbc.Driver"></property> </bean> <!--3.整合spring dataJpa--> <jpa:repositories base-package="com.citi.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> </beans>
新增entity包，编写两个实体类User，Role，两者为多对多关系，一个用户可以有多个角色，一个角色也包含了多个用户
public class User { private Long userId; private String userName; private Integer age; // 此处省略getter/setter/toString方法 }
public class Role { private Long roleId; private String roleName; // 此处省略getter/setter/toString方法
新增dao包，编写UserDao和RoleDao，并继承JpaRepository和JpaSpecificationExecutor
public interface UserDao extends JpaRepository<User,Long>, JpaSpecificationExecutor<User> { }
public interface RoleDao extends JpaRepository<Role,Long>, JpaSpecificationExecutor<Role> { }
在test包中新建测试类Many2ManyTest
@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(locations = "classpath:applicationContext.xml") public class Many2ManyTest { @Autowired private UserDao userDao; @Autowired private RoleDao roleDao; }
配置多对多映射关系
- 添加@Entity注解，表示该类是一个实体类
- 增加@Table注解，表明该实体类对应的表名称
- 增加@Id及@Column，建立实体类属性和数据库字段之间的映射关系
- 新增角色属性，并添加getter/setter方法，用户的角色是一组集合，用Set表示
- 在角色集合上增加@ManyToMany注解，表明多对多的关系
- @JoinTable表示配置中间表，name表示中间表的名称，joinColumns配置的是当前对象在中间表中的外键,name值得值中间表的主键，referencedColumnName当前类对应表的主键，inverseJoinColumns:对方对象在中间表的外键
@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; /** * 配置多对多的映射关系 * @ManyToMany：声明表的映射关系为多对多关系，targetEntity为对方实体类的字节码 * @JoinTable：配置中间表，name为中间表的名称， * joinColumns配置的是当前对象在中间表中的外键,name值得值中间表的主键，referencedColumnName当前类对应表的主键 * inverseJoinColumns:对方对象在中间表的外键 */ @ManyToMany(targetEntity = Role.class) @JoinTable(name = "sys_user_role", joinColumns = {@JoinColumn(name = "sys_user_id", referencedColumnName = "user_id")}, inverseJoinColumns = {@JoinColumn(name = "sys_role_id", referencedColumnName = "role_id")} ) private Set<Role> roleSet = new HashSet<>(); public Set<Role> getRoleSet() { return roleSet; } public void setRoleSet(Set<Role> roleSet) { this.roleSet = roleSet; }
@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; @ManyToMany(targetEntity = User.class) @JoinTable(name = "sys_user_role", joinColumns = {@JoinColumn(name = "sys_role_id", referencedColumnName = "role_id")}, inverseJoinColumns = {@JoinColumn(name = "sys_user_id", referencedColumnName = "user_id")} ) private Set<User> userSet = new HashSet<>(); public Set<User> getUserSet() { return userSet; } public void setUserSet(Set<User> userSet) { this.userSet = userSet; }
多对多表操作
在Many2ManyTest中新增方法testSave()
@Test @Transactional @Rollback(false) public void testSave(){ User user = new User(); user.setUserName("Thor"); Role role = new Role(); role.setRoleName("God"); userDao.save(user); roleDao.save(role); }
