Maven 版 JPA 最佳实践

项目结构图

数据库环境

• 数据库：MySQL
• 版本：5.x
• 数据库名：jpa-demo
• 用户名密码：root/1234

代码清单 1：数据库脚本：

/*
Navicat MySQL Data Transfer

Source Server         : localhost
Source Server Version : 50525
Source Host           : localhost:3306
Source Database       : jpa-demo

Target Server Type    : MYSQL
Target Server Version : 50525
File Encoding         : 65001

Date: 2014-11-20 20:09:27
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `address`
-- ----------------------------
DROP TABLE IF EXISTS `address`;
CREATE TABLE `address` (
  `addressID` int(11) NOT NULL,
  `city` varchar(55) NOT NULL,
  `street` varchar(55) NOT NULL,
  `zip` varchar(8) NOT NULL,
  PRIMARY KEY (`addressID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of address
-- ----------------------------
INSERT INTO `address` VALUES ('1', '深圳', '坂田市场', '518001');
INSERT INTO `address` VALUES ('2', '深圳', '坂田路口', '518002');
INSERT INTO `address` VALUES ('3', '深圳', '四季花城', '518003');

-- ----------------------------
-- Table structure for `userinfo`
-- ----------------------------
DROP TABLE IF EXISTS `userinfo`;
CREATE TABLE `userinfo` (
  `userID` int(11) NOT NULL,
  `username` varchar(20) NOT NULL,
  `birthday` datetime DEFAULT NULL,
  `sex` varchar(8) NOT NULL,
  `addressID` int(11) NOT NULL,
  PRIMARY KEY (`userID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of userinfo
-- ----------------------------
INSERT INTO `userinfo` VALUES ('1', '张金雄', null, 'male', '1');
INSERT INTO `userinfo` VALUES ('2', '李某某', null, 'male', '2');
INSERT INTO `userinfo` VALUES ('3', '王某某', '2006-08-10 00:00:00', 'female', '3');
INSERT INTO `userinfo` VALUES ('4', '陈某某', '2006-08-12 00:00:00', 'male', '3');

源代码

代码清单 2：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/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.coderdream</groupId>
	<artifactId>jpa-demo</artifactId>
	<packaging>war</packaging>
	<version>0.0.1-SNAPSHOT</version>
	<name>jpa-demo Maven Webapp</name>
	<url>http://maven.apache.org</url>
	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<junit.version>4.11</junit.version>
		<mysql.version>5.1.17</mysql.version>
		<slf.version>1.7.5</slf.version>
		<toplink.essentials.version>2.1-60f</toplink.essentials.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>${junit.version}</version>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>toplink.essentials</groupId>
			<artifactId>toplink-essentials</artifactId>
			<version>${toplink.essentials.version}</version>
		</dependency>

		<dependency>
			<groupId>toplink.essentials</groupId>
			<artifactId>toplink-essentials-agent</artifactId>
			<version>${toplink.essentials.version}</version>
		</dependency>

		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-log4j12</artifactId>
			<version>${slf.version}</version>
		</dependency>

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>${mysql.version}</version>
		</dependency>
	</dependencies>
	<build>
		<finalName>jpa-demo</finalName>
	</build>
</project>

代码清单 3：persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
	version="1.0">

	<persistence-unit name="piscesPU" transaction-type="RESOURCE_LOCAL">
		<provider>
			oracle.toplink.essentials.PersistenceProvider
		</provider>
		<class>com.coderdream.model.UserInfo</class>
		<class>com.coderdream.model.Address</class>
		<properties>
			<!-- 数据库连接配置, JDBC驱动 -->
			<property name="toplink.jdbc.driver" value="com.mysql.jdbc.Driver" />
			<!-- 数据库连接配置,URL -->
			<property name="toplink.jdbc.url" value="jdbc:mysql://localhost:3306/jpa-demo" />
			<!-- 数据库连接配置, 用户名 -->
			<property name="toplink.jdbc.user" value="root" />
			<!-- 数据库连接配置, 密码 -->
			<property name="toplink.jdbc.password" value="1234" />
		</properties>
	</persistence-unit>

</persistence>

代码清单 4：Address.java

package com.coderdream.model;

import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Address implements Serializable {
	// 地址id, 不能为空, 必须唯一
	@Id
	@Column(name = "addressid", unique = true, nullable = false)
	private int addressid;

	// 城市, 不能为空
	@Column(name = "city", nullable = false)
	private String city;

	// 街道, 不能为空
	@Column(name = "street", nullable = false)
	private String street;

	// 邮政编码, 不能为空
	@Column(name = "zip", nullable = false)
	private String zip;

	public Address() {
	}

	public Address(int addressid) {
		this.setAddressid(addressid);
	}

	public int getAddressid() {
		return this.addressid;
	}

	public void setAddressid(int addressid) {
		this.addressid = addressid;
	}

	public String getCity() {
		return this.city;
	}

	public void setCity(String city) {
		this.city = city;
	}

	public String getStreet() {
		return street;
	}

	public void setStreet(String street) {
		this.street = street;
	}

	public String getZip() {
		return this.zip;
	}

	public void setZip(String zip) {
		this.zip = zip;
	}

	@Override
	public int hashCode() {
		return this.addressid;
	}

	@Override
	public boolean equals(Object object) {
		if (!(object instanceof Address))
			return false;
		final Address other = (Address) object;
		return this.addressid == other.addressid;
	}

	@Override
	public String toString() {
		return "Address[addressid=" + getAddressid() + ", city='" + getCity() + "', street='" + getStreet() + "', zip='" + getZip() + "";
	}
}

代码清单 5：UserInfo.java

package com.coderdream.model;

import java.io.Serializable;
import java.sql.Timestamp;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import static javax.persistence.CascadeType.*;

@Entity
public class UserInfo implements Serializable {
	// 用户id, 不能为空, 必须唯一
	@Id
	@Column(name = "userid", unique = true, nullable = false)
	private int userid;

	// 用户名, 不能为空
	@Column(name = "userName", nullable = false)
	private String userName;

	// 性别, 不能为空
	@Column(name = "sex", nullable = false)
	private String sex;

	// 出生日期, 可以为空
	@Column(name = "birthday")
	private Timestamp birthday;

	// 地址, 不能为空
	// PERSIST 表示更新、新增UserInfo数据时会同时更新、新增Address的数据
	// REMOVE 表示从数据库删除UserInfo会同时删除Address表中对应的数据
	@OneToOne(cascade = { PERSIST, REMOVE })
	@JoinColumn(name = "addressID", nullable = false)
	private Address address;

	public UserInfo() {
	}

	public UserInfo(int userid) {
		this.setUserid(userid);
	}

	@Override
	public int hashCode() {
		return this.getUserid();
	}

	@Override
	public boolean equals(Object object) {
		if (!(object instanceof UserInfo))
			return false;
		final UserInfo other = (UserInfo) object;
		return this.userid == other.userid;
	}

	@Override
	public String toString() {
		return "UserInfo[userid=" + this.userid + ", userName='" + userName + "', sex='" + sex + "', birthday=" + birthday + ", address="
				+ address + "";
	}

	public int getUserid() {
		return userid;
	}

	public void setUserid(int userid) {
		this.userid = userid;
	}

	public String getUserName() {
		return userName;
	}

	public void setUserName(String userName) {
		this.userName = userName;
	}

	public Timestamp getBirthday() {
		return birthday;
	}

	public void setBirthday(Timestamp birthday) {
		this.birthday = birthday;
	}

	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex = sex;
	}

	public Address getAddress() {
		return address;
	}

	public void setAddress(Address address) {
		this.address = address;
	}
}

代码清单 6：SimpleService.java

package com.coderdream.service;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import com.coderdream.model.Address;
import com.coderdream.model.UserInfo;

public class SimpleService {

	/**
	 * 删除用户id=6的数据
	 */
	public static void delete() {
		final EntityManagerFactory emf = Persistence.createEntityManagerFactory("piscesPU");
		final EntityManager em = emf.createEntityManager();
		// 找不到数据的话这里会抛异常
		UserInfo info = em.find(UserInfo.class, 6);
		try {
			em.getTransaction().begin();
			em.remove(info);
			em.getTransaction().commit();
		} finally {
			em.close();
		}
	}

	/**
	 * 修改用户id=6的数据
	 */
	public static void update() {
		final EntityManagerFactory emf = Persistence.createEntityManagerFactory("piscesPU");
		final EntityManager em = emf.createEntityManager();
		// 找不到数据的话这里会抛异常
		UserInfo info = em.find(UserInfo.class, 6);
		info.setUserName("哈哈");
		info.getAddress().setStreet("坂田2");
		try {
			em.getTransaction().begin();
			// 自动将info更新到数据库
			em.getTransaction().commit();
		} finally {
			em.close();
		}
	}

	/**
	 * 查询所有用户数据
	 */
	public static void query() {
		final EntityManagerFactory emf = Persistence.createEntityManagerFactory("piscesPU");
		long s = System.currentTimeMillis();
		// 数据库连接失败这里会抛出异常
		final EntityManager em = emf.createEntityManager();
		long e = System.currentTimeMillis();
		System.out.println("连接数据库耗时: " + (e - s) + "毫秒");
		// 获取数据
		@SuppressWarnings("unchecked")
		List<UserInfo> list = em.createQuery("SELECT a FROM UserInfo a").getResultList();
		int i = 0;
		for (UserInfo info : list) {
			System.out.println("第" + (++i) + "个值为: " + info);
		}
		em.close();
	}

	/**
	 * 创建用户id=6的一条数据, 地址id=6
	 */
	public static void create() {
		final EntityManagerFactory emf = Persistence.createEntityManagerFactory("piscesPU");
		final EntityManager em = emf.createEntityManager();

		UserInfo info = new UserInfo(6);
		info.setSex("male");
		info.setUserName("张某某");
		info.setBirthday(new java.sql.Timestamp(System.currentTimeMillis()));
		Address naddr = new Address(6);
		naddr.setCity("深圳");
		naddr.setStreet("坂田");
		naddr.setZip("518000");
		info.setAddress(naddr);

		try {
			em.getTransaction().begin();
			em.persist(info);
			em.getTransaction().commit();
		} finally {
			em.close();
		}
	}

	/**
	 * 主函数
	 */
	public static void main(String[] args) throws Throwable {
		SimpleService.query();
		SimpleService.create();
		System.out.println("新增一条数据后进行查询");
		SimpleService.query();
		SimpleService.update();
		System.out.println("修改一条数据后进行查询");
		SimpleService.query();
		SimpleService.delete();
		System.out.println("删除一条数据后进行查询");
		SimpleService.query();
	}
}

运行结果

[TopLink Info]: 2014.11.20 08:24:08.134--ServerSession(1112823384)--TopLink, version: Oracle TopLink Essentials - 2.1 (Build 60f (01/07/2009))
[TopLink Info]: 2014.11.20 08:24:08.822--ServerSession(1112823384)--file:/E:/E_441_64/workspace/jpa-demo/target/classes/-piscesPU login successful
连接数据库耗时: 1264毫秒
第1个值为: UserInfo[userid=1, userName='张金雄', sex='male', birthday=null, address=Address[addressid=1, city='深圳', street='坂田市场', zip='518001
第2个值为: UserInfo[userid=2, userName='李某某', sex='male', birthday=null, address=Address[addressid=2, city='深圳', street='坂田路口', zip='518002
第3个值为: UserInfo[userid=3, userName='王某某', sex='female', birthday=2006-08-10 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
第4个值为: UserInfo[userid=4, userName='陈某某', sex='male', birthday=2006-08-12 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
新增一条数据后进行查询
连接数据库耗时: 0毫秒
第1个值为: UserInfo[userid=1, userName='张金雄', sex='male', birthday=null, address=Address[addressid=1, city='深圳', street='坂田市场', zip='518001
第2个值为: UserInfo[userid=2, userName='李某某', sex='male', birthday=null, address=Address[addressid=2, city='深圳', street='坂田路口', zip='518002
第3个值为: UserInfo[userid=3, userName='王某某', sex='female', birthday=2006-08-10 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
第4个值为: UserInfo[userid=4, userName='陈某某', sex='male', birthday=2006-08-12 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
第5个值为: UserInfo[userid=6, userName='张某某', sex='male', birthday=2014-11-20 20:24:09.102, address=Address[addressid=6, city='深圳', street='坂田', zip='518000
修改一条数据后进行查询
连接数据库耗时: 0毫秒
第1个值为: UserInfo[userid=1, userName='张金雄', sex='male', birthday=null, address=Address[addressid=1, city='深圳', street='坂田市场', zip='518001
第2个值为: UserInfo[userid=2, userName='李某某', sex='male', birthday=null, address=Address[addressid=2, city='深圳', street='坂田路口', zip='518002
第3个值为: UserInfo[userid=3, userName='王某某', sex='female', birthday=2006-08-10 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
第4个值为: UserInfo[userid=4, userName='陈某某', sex='male', birthday=2006-08-12 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
第5个值为: UserInfo[userid=6, userName='哈哈', sex='male', birthday=2014-11-20 20:24:09.102, address=Address[addressid=6, city='深圳', street='坂田2', zip='518000
删除一条数据后进行查询
连接数据库耗时: 0毫秒
第1个值为: UserInfo[userid=1, userName='张金雄', sex='male', birthday=null, address=Address[addressid=1, city='深圳', street='坂田市场', zip='518001
第2个值为: UserInfo[userid=2, userName='李某某', sex='male', birthday=null, address=Address[addressid=2, city='深圳', street='坂田路口', zip='518002
第3个值为: UserInfo[userid=3, userName='王某某', sex='female', birthday=2006-08-10 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003
第4个值为: UserInfo[userid=4, userName='陈某某', sex='male', birthday=2006-08-12 00:00:00.0, address=Address[addressid=3, city='深圳', street='四季花城', zip='518003

完整工程源代码

下载地址：http://download.****.net/detail/xuxiheng/8181849

参考文档

1. 在Java SE环境下使用JPA1.0(1)

2. Toplink JPA简介