Maven 版 JPA 最佳实践(转)

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：

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/* 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

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<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

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<?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

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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

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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

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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

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[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.csdn.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

http://www.cnblogs.com/ctoroad/p/4111447.html