Spring Data JPA使用复合主键

我不是女神ヾ 2022-06-13 07:29 244阅读 0赞

演示环境

MySQL 5.7

JDK1.8

spring-data-jpa 1.10.4.RELEASE

hibernate 5.1.2.Final

这里演示一个余额宝的例子，一个用户一天一条记录，表示一个用户一天的收益情况。其中，用户ID，日期是复合主键

项目总体结构如下：

![Center][]

下面依次贴出源代码

pom.xml

<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.pp.jpa</groupId>
    	<artifactId>springdata-jpa</artifactId>
    	<version>1.0.0</version>
    	<packaging>jar</packaging>
    
    	<name>springdata-jpa</name>
    	<url>http://maven.apache.org</url>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<maven.compiler.source>1.8</maven.compiler.source>
    		<maven.compiler.target>1.8</maven.compiler.target>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>5.1.40</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.data</groupId>
    			<artifactId>spring-data-jpa</artifactId>
    			<version>1.10.4.RELEASE</version>
    		</dependency>
    		<dependency>
    			<groupId>org.hibernate</groupId>
    			<artifactId>hibernate-core</artifactId>
    			<version>5.1.2.Final</version>
    		</dependency>
    		<dependency>
    			<groupId>org.hibernate</groupId>
    			<artifactId>hibernate-entitymanager</artifactId>
    			<version>5.1.2.Final</version>
    		</dependency>
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<version>4.12</version>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    
    </project>

下面依次是Java源码

package com.pp.jpa.config;
    
    import javax.persistence.EntityManagerFactory;
    import javax.sql.DataSource;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.orm.jpa.JpaTransactionManager;
    import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
    import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
    import org.springframework.transaction.PlatformTransactionManager;
    
    import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
    
    @Configuration
    public class JPAConfiguration {
    
    	@Bean
    	public DataSource createDataSource(){
    		MysqlDataSource ds = new MysqlDataSource();
    		ds.setURL("jdbc:mysql://127.0.0.1:3306/jpa");
    		ds.setUser("root");
    		ds.setPassword("admin123");
    		return ds;
    	}
    	
    	@Bean(name="entityManagerFactory")
    	public EntityManagerFactory createEntityManagerFactory(DataSource dataSource){
    		LocalContainerEntityManagerFactoryBean entityManagerFactory = new LocalContainerEntityManagerFactoryBean();
    		entityManagerFactory.setDataSource(dataSource);
    		
    		HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter();
    		jpaVendorAdapter.setGenerateDdl(true);
    		jpaVendorAdapter.setShowSql(true);
    		entityManagerFactory.setPackagesToScan("com.pp.jpa.entity");
    		entityManagerFactory.setJpaVendorAdapter(jpaVendorAdapter);
    		entityManagerFactory.afterPropertiesSet();
    		return entityManagerFactory.getObject();
    	}
    	
    	@Bean(name="transactionManager")
    	public PlatformTransactionManager createPlatformTransactionManager(EntityManagerFactory entityManagerFactory){
    		JpaTransactionManager transactionManager = new JpaTransactionManager();
    		transactionManager.setEntityManagerFactory(entityManagerFactory);
    		return transactionManager;
    	}
    }

package com.pp.jpa.entity;
    
    import java.io.Serializable;
    
    import javax.persistence.Embeddable;
    
    /**
     * 主键 
     * 代表复合主键的实体bean需要实现Serializable接口
     */
    @Embeddable
    public class UserFundPrimarykey implements Serializable {
    	
    	private static final long serialVersionUID = 1L;
    
    	//用户ID
    	private Integer userId;
    	
    	/**
    	 * 日期，格式yyyy-MM-dd
    	 */
    	private String date;
    	
    	public UserFundPrimarykey() {}
    	
    	public UserFundPrimarykey(Integer userId, String date) {
    		this.userId = userId;
    		this.date = date;
    	}
    
    	public Integer getUserId() {
    		return userId;
    	}
    
    	public void setUserId(Integer userId) {
    		this.userId = userId;
    	}
    
    	public String getDate() {
    		return date;
    	}
    
    	public void setDate(String date) {
    		this.date = date;
    	}
    
    	@Override
    	public String toString() {
    		return "UserFundPrimarykey [userId=" + userId + ", date=" + date + "]";
    	}
    }

package com.pp.jpa.entity;
    
    import java.math.BigDecimal;
    
    import javax.persistence.Column;
    import javax.persistence.EmbeddedId;
    import javax.persistence.Entity;
    import javax.persistence.Table;
    
    /**
     *  模拟一个余额宝的功能
     *  一条记录代表一个用户一天的收益信息（本金，利率，利息）
     */
    @Entity
    @Table(name = "user_funds")
    public class UserFund {
    	
    	/**
    	 * 主键
    	 * 复合主键不能用@Id，需要用@EmbeddedId。插入数据的时候必须手工赋值
    	 */
    	@EmbeddedId
    	private UserFundPrimarykey userFundPK;
    	
    	//本金
    	@Column(precision=18, scale=5)
    	private BigDecimal principal;
    	
    	//利率（5%传0.05）
    	@Column(precision=18, scale=5)
    	private BigDecimal rate;
    	
    	/**
    	 * 当天收益（日利息=本金*利率/365）
    	 * 保留2位小数
    	 */
    	@Column(precision=18, scale=2)
    	private BigDecimal interest;
    
    	public UserFundPrimarykey getUserFundPK() {
    		return userFundPK;
    	}
    
    	public void setUserFundPK(UserFundPrimarykey userFundPK) {
    		this.userFundPK = userFundPK;
    	}
    
    	public BigDecimal getPrincipal() {
    		return principal;
    	}
    
    	public void setPrincipal(BigDecimal principal) {
    		this.principal = principal;
    	}
    
    	public BigDecimal getRate() {
    		return rate;
    	}
    
    	public void setRate(BigDecimal rate) {
    		this.rate = rate;
    	}
    
    	public BigDecimal getInterest() {
    		return interest;
    	}
    
    	public void setInterest(BigDecimal interest) {
    		this.interest = interest;
    	}
    
    	@Override
    	public String toString() {
    		return "UserFund [userFundPK=" + userFundPK + ", principal=" + principal + ", rate=" + rate + ", interest="
    				+ interest + "]";
    	}
    }

package com.pp.repository;
    
    import org.springframework.data.repository.CrudRepository;
    
    import com.pp.jpa.entity.UserFund;
    import com.pp.jpa.entity.UserFundPrimarykey;
    
    public interface UserFundRepository extends CrudRepository<UserFund, UserFundPrimarykey> {
    	
    }

启动类

package com.pp.jpa;
    
    import java.math.BigDecimal;
    import java.math.RoundingMode;
    
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
    import org.springframework.transaction.annotation.EnableTransactionManagement;
    
    import com.pp.jpa.entity.UserFund;
    import com.pp.jpa.entity.UserFundPrimarykey;
    import com.pp.repository.UserFundRepository;
    
    @ComponentScan
    @EnableJpaRepositories(value="com.pp")
    @EnableTransactionManagement
    public class App {
    	public static void main(String[] args) throws Exception {
    		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(App.class);
    		
    		UserFund uf1 = new UserFund();
    		//必须手动设置主键
    		uf1.setUserFundPK(new UserFundPrimarykey(1, "2017-07-01"));
    		uf1.setRate(new BigDecimal("0.041"));
    		uf1.setPrincipal(new BigDecimal("10000"));
    		//截断，只保留两位小数
    		uf1.setInterest(uf1.getRate().multiply(uf1.getPrincipal()).divide(new BigDecimal("365"), 2, RoundingMode.DOWN));
    		
    		UserFund uf2 = new UserFund();
    		//必须手动设置主键
    		uf2.setUserFundPK(new UserFundPrimarykey(2, "2017-07-01"));
    		uf2.setRate(new BigDecimal("0.041"));
    		uf2.setPrincipal(new BigDecimal("20000"));
    		//截断，只保留两位小数
    		uf2.setInterest(uf2.getRate().multiply(uf2.getPrincipal()).divide(new BigDecimal("365"), 2, RoundingMode.DOWN));
    		
    		UserFundRepository ur = context.getBean(UserFundRepository.class);
    		ur.save(uf1);
    		ur.save(uf2);
    		
    		ur.findAll().forEach(System.out::println);
    		
    		//查询用户ID=2，在2017-07-01这一天的收益
    		System.out.println(ur.findOne(new UserFundPrimarykey(2, "2017-07-01")));
    		context.close();
    	}
    }

一些注意事项和做法已经在备注中有写，大家模仿着写就OK了

直接运行main方法，控制台输出如下信息

Hibernate: select userfund0_.date as date1_0_0_, userfund0_.userId as userId2_0_0_, userfund0_.interest as interest3_0_0_, userfund0_.principal as principa4_0_0_, userfund0_.rate as rate5_0_0_ from user_funds userfund0_ where userfund0_.date=? and userfund0_.userId=?
    Hibernate: insert into user_funds (interest, principal, rate, date, userId) values (?, ?, ?, ?, ?)
    Hibernate: select userfund0_.date as date1_0_0_, userfund0_.userId as userId2_0_0_, userfund0_.interest as interest3_0_0_, userfund0_.principal as principa4_0_0_, userfund0_.rate as rate5_0_0_ from user_funds userfund0_ where userfund0_.date=? and userfund0_.userId=?
    Hibernate: insert into user_funds (interest, principal, rate, date, userId) values (?, ?, ?, ?, ?)
    Hibernate: select userfund0_.date as date1_0_, userfund0_.userId as userId2_0_, userfund0_.interest as interest3_0_, userfund0_.principal as principa4_0_, userfund0_.rate as rate5_0_ from user_funds userfund0_
    UserFund [userFundPK=UserFundPrimarykey [userId=1, date=2017-07-01], principal=10000.00000, rate=0.04100, interest=1.12]
    UserFund [userFundPK=UserFundPrimarykey [userId=2, date=2017-07-01], principal=20000.00000, rate=0.04100, interest=2.24]
    Hibernate: select userfund0_.date as date1_0_0_, userfund0_.userId as userId2_0_0_, userfund0_.interest as interest3_0_0_, userfund0_.principal as principa4_0_0_, userfund0_.rate as rate5_0_0_ from user_funds userfund0_ where userfund0_.date=? and userfund0_.userId=?
    UserFund [userFundPK=UserFundPrimarykey [userId=2, date=2017-07-01], principal=20000.00000, rate=0.04100, interest=2.24]

查询数据库

select \*\* from user\_funds;

![Center 1][]

最后说一句，余额宝的利息好低啊，一万块钱存一天，只有1块钱左右

[Center]: /images/20220613/10c8edc7a97944d89fa83560deb2f2cb.png
[Center 1]: /images/20220613/50c0646a7edf41f6be44272dace4d357.png