Eclipse jee下JPA的开发配置
1、配置JPA。点击window --> Preferences的“参数选择”对象框当中选择JPA；接着，点击Configure User Libraries，在用户类库当中将OpenJPA的核心包以及依赖的外部包文件加到OpenJPA Library当中。配置后的效果图如下所示：
2、配置数据库连接，点击window --> Preferences的“参数选择”对象框当中选择Connectivity--> Driver Definitions，在数据库的选择项当中选择Mysql，并添加Mysql JDBC Driver。最终的效果如下图所示：
3、创建新的JPA Project：点击File --> New --> Other，在弹出的创建向导当中选择JPA，如下图所示：
4、点击Next（下一步）。在窗口当中输入项目名称，比如JPATraining，其它默认
5、点击Next(下一步)
6、各项默认就可以了，点击下一步
7、一切都默认就可以，因为之前已经配置完了。最后点击Finish。
最后，可以在Project Explorer当中看到src/META-INF/下面多了两个文件，一个叫persistence.xml，另一个叫orm.xml
8、程序的编写：
1、数据库脚本
程序代码 Create TABLE ECA_USER( ID INT NOT NULL AUTO_INCREMENT, NAME VARCHAR(20) NOT NULL, LOGINID VARCHAR(20) NOT NULL, PASSWORD VARCHAR(32) NOT NULL, AGE INT NOT NULL, PRIMARY KEY(ID));
2，Entity
程序代码 package com.suneca.entity;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.Id;import javax.persistence.Table;import javax.persistence.GeneratedValue;import static javax.persistence.GenerationType.IDENTITY;/*** * @author ChenYuzhe* @version 1.0* Create-Time：2008-7-16 下午06:55:22*/@Entity@Table(name="ECA_USER")public class User { @Id @GeneratedValue(strategy=IDENTITY) private int id; @Column(name = "NAME") private String name; @Column(name = "LOGINID") private String loginId; @Column(name = "PASSWORD") private String password; @Column(name = "AGE") private int age; public int getId() { return id; } public String getName() { return name; } public String getLoginId() { return loginId; } public String getPassword() { return password; } public int getAge() { return age; } public void setId(int id) { this.id = id; } public void setName(String name) { this.name = name; } public void setLoginId(String loginId) { this.loginId = loginId; } public void setPassword(String password) { this.password = password; } public void setAge(int age) { this.age = age; } }
3，测试类的编写
程序代码 package com.suneca.test;import javax.persistence.EntityManager;import javax.persistence.EntityManagerFactory;import javax.persistence.Persistence;import javax.persistence.EntityTransaction;import com.suneca.entity.User;/*** * @author ChenYuzhe* @version 1.0* Create-Time：2008-7-16 下午06:55:08*/public class UserTest { public static void main(String[] args){ // get Entity Manager EntityManagerFactory factory = Persistence.createEntityManagerFactory("MyJPA"); long startTime = System.currentTimeMillis(); EntityManager em = factory.createEntityManager(); // get Transaction and Begin Transaction EntityTransaction transaction = em.getTransaction(); transaction.begin(); User user = new User(); user.setName("陈毓哲"); user.setLoginId("zizz"); user.setPassword("admin"); user.setAge(28); em.persist(user); // Commit transaction.commit(); long endTime = System.currentTimeMillis(); System.out.println(endTime - startTime); em.close(); }}
4，persistence.xml的修改
程序代码 <?xml version="1.0" encoding="UTF-8"?><persistence version="1.0" 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"> <persistence-unit name="MyJPA" transaction-type="RESOURCE_LOCAL"> <!-- 定义jpa的Provider --> <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider> <!-- 定义持久化实体 --> <class>com.suneca.entity.User</class> <!-- 定义jpa的数据库参数 --> <properties> <property name="openjpa.ConnectionURL" value="jdbc:mysql://localhost:3306/suneca"/> <property name="openjpa.ConnectionDriverName" value="com.mysql.jdbc.Driver"/> <property name="openjpa.ConnectionUserName" value="root"/> <property name="openjpa.ConnectionPassword" value="admin"/> </properties> </persistence-unit></persistence>