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  3. jpa建表一对多

jpa建表一对多

mac2022-06-30  25

pom.xml:

<?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>cn.dy</groupId> <artifactId>springJpaOneToOne</artifactId> <version>1.0-SNAPSHOT</version> <properties> <spring.version>4.2.4.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> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <!--spring start--> <!--spring aop--> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>1.6.8</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <!--spring aop--> <!--spring ioc--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <!--spring ioc--> <!--spring end--> <!--spring 对orm框架的支持包--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <!--spring 对orm框架的支持包--> <!--hibernate start--> <!--hibernate 核心包--> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>${hibernate.version}</version> </dependency> <!--hibernate 对JPA实现的包--> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>${hibernate.version}</version> </dependency> <!--hibernate 验证包--> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <version>5.2.1.Final</version> </dependency> <!--hibernate end--> <dependency> <groupId>c3p0</groupId> <artifactId>c3p0</artifactId> <version>${c3p0.version}</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>${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> <!--mysql的驱动包--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>${mysql.version}</version> </dependency> <!--spring dataJpa 的坐标--> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-jpa</artifactId> <version>1.9.0.RELEASE</version> </dependency> <!--spring 测试 的坐标--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> <!-- el 标签 的坐标--> <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 标签 的坐标--> </dependencies></project>resources:　　applicationContext.xml: <?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"> <!--1 创建数据库的连接池--> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="password" value="root"/> <property name="user" value="root"/> <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/spring_data?characterEncoding=utf-8"/> <property name="driverClass" value="com.mysql.jdbc.Driver"/> </bean> <!--2 工厂类对象--> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <!--数据源--> <property name="dataSource" ref="dataSource"/> <!--实体类的扫描器--> <property name="packagesToScan" value="cn.dy.jpa.entity"/> <!--jpa配置供应商的适配器--> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <!-- 指定数据库类型--> <property name="database" value="MYSQL"/> <!-- 是否自动创建数据库表--> <property name="generateDdl" value="false"/> <!-- 数据库方言 支持的特有语法--> <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect"/> <!--是否向控制台输出语句 update hibernate.hbm2ddl.auto--> <property name="showSql" value="true"/> </bean> </property> <property name="jpaProperties"> <props> <prop key="hibernate.hbm2ddl.auto">update</prop> </props> </property> </bean> <!--配置事物--> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory"/> </bean> <!--一般出现在sevice层 start--> <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> <!--aop--> <aop:config> <aop:pointcut id="pointcut" expression="execution(* cn.dy.jpa.service.*.*(..))"/> <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut"/> </aop:config> <!--一般出现在sevice层 end--><!-- <context:component-scan base-package="cn.dy.jpa"></context:component-scan>--><!-- dao--> <jpa:repositories base-package="cn.dy.jpa.dao" transaction-manager-ref="transactionManager" entity-manager-factory-ref="entityManagerFactory"/></beans> entity:　　Tea主表： package cn.dy.jpa.entity;import javax.persistence.*;import java.io.Serializable;import java.util.HashSet;import java.util.Set;/** * author:dingyi * time:2019/8/20 0020 14:57 */// 声明该类是jpa的实体类@Entity@Table(name = "cust_tea")public class Tea implements Serializable { @GeneratedValue(strategy = GenerationType.IDENTITY) @Id @Column(name="tea_id") private long teaId; @Column(name="tea_name") private String teaName; @Column(name="tea_sex") private String teaSex; @Column(name="tea_age") private String teaAge; @Column(name="tea_Job") private String teaJob; // 配置教师与学生之间的关系 （一对多关系） /** * 使用注解的形式配置多表关系 * 1.声明关系 * @OneToMany; 配置一对多关系 * 2.配置外键（中间表） * @JoinColumn:配置外键 * name 外键字段名称 * referencedColumnName：参照的主表字段名称 * 在教师实体类上（一的一方）添加了外键配置，所以对于学生而言，也具备了维护外键的作用 */ @OneToMany(cascade = CascadeType.ALL,fetch = FetchType.EAGER)// @JoinColumn(name = "teaid",referencedColumnName = "tea_id") private Set<Stu> Stus=new HashSet<>(); public long getTeaId() { return teaId; } public void setTeaId(long teaId) { this.teaId = teaId; } public String getTeaName() { return teaName; } public void setTeaName(String teaName) { this.teaName = teaName; } public String getTeaSex() { return teaSex; } public void setTeaSex(String teaSex) { this.teaSex = teaSex; } public String getTeaAge() { return teaAge; } public void setTeaAge(String teaAge) { this.teaAge = teaAge; } public String getTeaJob() { return teaJob; } public void setTeaJob(String teaJob) { this.teaJob = teaJob; } public Set<Stu> getStus() { return Stus; } public void setStus(Set<Stu> stus) { Stus = stus; } @Override public String toString() { return "Tea{" + "teaId=" + teaId + ", teaName='" + teaName + '\'' + ", teaSex='" + teaSex + '\'' + ", teaAge='" + teaAge + '\'' + ", teaJob='" + teaJob + '\'' + '}'; }} Stu从表： package cn.dy.jpa.entity;import javax.persistence.*;import java.io.Serializable;/** * author:dingyi * time:2019/8/20 0020 17:32 */@Entity@Table(name = "cust_stu")public class Stu implements Serializable { @GeneratedValue(strategy = GenerationType.IDENTITY) @Id @Column(name = "stu_id") private Long stuId; @Column(name = "stu_name") private String stuName; @Column(name = "stu_sex") private String stuSex; @Column(name = "stu_age") private String stuAge; /** * 配置学生到教师的多对一关系 * 使用注解的形式配置多对一关系 * 1.配置表关系 * @ManyToOne: 配置多对一关系 * 2.配置外键（中间表） * 配置外键的过程，配置到了多的一方，就会再多的一方维护外键 */ @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY) @JoinColumn(name = "stuid",referencedColumnName = "tea_id") private Tea tea; public Long getStuId() { return stuId; } public void setStuId(Long stuId) { this.stuId = stuId; } public String getStuName() { return stuName; } public void setStuName(String stuName) { this.stuName = stuName; } public String getStuSex() { return stuSex; } public void setStuSex(String stuSex) { this.stuSex = stuSex; } public String getStuAge() { return stuAge; } public void setStuAge(String stuAge) { this.stuAge = stuAge; } public Tea getTea() { return tea; } public void setTea(Tea tea) { this.tea = tea; } @Override public String toString() { return "Stu{" + "stuId=" + stuId + ", stuName='" + stuName + '\'' + ", stuSex='" + stuSex + '\'' + ", stuAge='" + stuAge + '\'' + '}'; }} TeaDao: package cn.dy.jpa.dao;/** * author:dingyi * time:2019/8/20 0020 18:43 */import cn.dy.jpa.entity.Tea;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.data.jpa.repository.JpaSpecificationExecutor;public interface TeaDao extends JpaRepository<Tea,Long>, JpaSpecificationExecutor<Tea> {}StuDao: package cn.dy.jpa.dao;import cn.dy.jpa.entity.Stu;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.data.jpa.repository.JpaSpecificationExecutor;/** * author:dingyi * time:2019/8/20 0020 18:48 */public interface StuDao extends JpaRepository<Stu,Long>, JpaSpecificationExecutor<Stu> {} test测试1:　　　　 import cn.dy.jpa.dao.StuDao;import cn.dy.jpa.dao.TeaDao;import cn.dy.jpa.entity.Stu;import cn.dy.jpa.entity.Tea;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.test.annotation.Commit;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;/** * author:dingyi * time:2019/8/20 0020 19:17 */@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration("classpath*:applicationContext.xml")public class testOneToMany { @Autowired TeaDao teaDao; @Autowired StuDao stuDao; /** * 保存一个教师，一个学生 * */ @Test @Transactional //配置事务 @Commit @Rollback(false) //不自动回滚 public void testAdd(){ //创建一个教师，创建一个学生 Tea tea = new Tea(); tea.setTeaName("吉泽明步"); tea.setTeaAge("34"); tea.setTeaSex("女"); tea.setTeaJob("教师"); Stu stu1 = new Stu(); stu1.setStuName("张敏"); stu1.setStuSex("女"); stu1.setStuAge("32"); Stu stu2 = new Stu(); stu2.setStuName("思思"); stu2.setStuSex("女"); stu2.setStuAge("33"); tea.getStus().add(stu1); tea.getStus().add(stu2); stu1.setTea(tea); stu2.setTea(tea); teaDao.save(tea); stuDao.save(stu1); stuDao.save(stu2); }} test测试2: import cn.dy.jpa.dao.StuDao;import cn.dy.jpa.dao.TeaDao;import cn.dy.jpa.entity.Stu;import cn.dy.jpa.entity.Tea;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.test.annotation.Commit;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;import java.util.Set;/** * author:dingyi * time:2019/8/21 0021 16:24 */@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration("classpath*:applicationContext.xml")public class ObJQuerytest { @Autowired TeaDao teaDao; @Autowired StuDao stuDao; /** * could not initialize proxy - no Session 报错原因： @Transactional */ @Test @Transactional @Commit @Rollback(false) public void testQuery(){ //查询id为1的教师 Tea teaDaoOne = teaDao.getOne(1L); //对象导航查询，此教师下的所有学生 Set<Stu> stus = teaDaoOne.getStus(); for (Stu stu:stus){ System.out.println(stu); } }}

转载于:https://www.cnblogs.com/dingyi-boss/p/11439624.html

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