package com.watchfree.entity;import javax.persistence.Entity;import javax.persistence.Id;/** *  创建实体类 * @author watchfree * @date 2016年12月6日下午7:12:43 */@Entitypublic class Employee {        @Id private int id ;    private String name ;     private long salary ;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public long getSalary() {        return salary;    }    public void setSalary(long salary) {        this.salary = salary;    }  public Employee() {            }        public Employee(int id){        this.id = id ;    }        @Override    public String toString() {        // TODO Auto-generated method stub        return "employee: id: "+this.id + " ,name: "+this.name + " ,saray: "+this.salary;    }}

<?xml version="1.0" encoding="UTF-8"?><persistence version="2.1"    xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">    <persistence-unit name="EmployeeService"        transaction-type="RESOURCE_LOCAL">        <class>com.watchfree.entity.Employee</class>        <properties>        <!-- 数据库连接操作 -->            <property name="javax.persistence.jdbc.driver" value="http://www.mamicode.com/com.mysql.jdbc.Driver" />            <property name="javax.persistence.jdbc.url" value="http://www.mamicode.com/jdbc:mysql://localhost/jpa" />            <property name="javax.persistence.jdbc.user" value="http://www.mamicode.com/root" />            <property name="javax.persistence.jdbc.password" value="http://www.mamicode.com/root" />            <!-- 配置 JPA 实现产品的基本属性. 配置 hibernate 的基本属性 -->            <property name="hibernate.format_sql" value="http://www.mamicode.com/true" />            <property name="hibernate.show_sql" value="http://www.mamicode.com/true" />            <property name="hibernate.hbm2ddl.auto" value="http://www.mamicode.com/update" />        </properties>    </persistence-unit></persistence>

package com.watchfree.service;import javax.persistence.EntityManager;import com.watchfree.entity.Employee;/** * 操作Employee实体的服务类 *  * @author watchfree * @date 2016年12月6日下午6:47:42 */public class EmployeeService {    protected EntityManager entityManager;    public EmployeeService(EntityManager entityManager) {        this.entityManager = entityManager;    }    /**     * 创建Employee方法     *      * @param id     * @param name     * @param salary     * @return     */    public Employee createEmployee(int id, String name, long salary) {        Employee employee = new Employee(id);        employee.setName(name);        employee.setSalary(salary);        entityManager.persist(employee);        return employee;    }    /**     * 删除     *      * @param id     */    public void removeEmployee(int id) {        Employee employee = findEmployee(id);        if (employee != null) {            entityManager.remove(employee);        }    }    /**     * 查找     *      * @param id     * @return     */    public Employee findEmployee(int id) {        return entityManager.find(Employee.class, id);    }    /**     * 更新     * @param id     * @param raise     * @return     */    public Employee raiseEmployeeSalary(int id, long raise) {        Employee employee = entityManager.find(Employee.class, id);        if (employee != null) {            employee.setSalary(employee.getSalary() + raise);        }        return employee;    }

    /**
    * 查詢所有
    * @return
    */
      public List<Employee> findAllEmployees() {
         TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e",Employee.class);
        return query.getResultList();
       }

}

package com.watchfree.test;import javax.persistence.EntityManager;import javax.persistence.EntityManagerFactory;import javax.persistence.EntityTransaction;import javax.persistence.Persistence;import org.junit.After;import org.junit.Before;import org.junit.Test;import com.watchfree.entity.Employee;import com.watchfree.service.EmployeeService;public class EmpoyeeTest {        private EntityManagerFactory entityManagerFactory ;    private EntityManager entityManager ;    private EntityTransaction transaction ;    private EmployeeService employeeService ;        @Before    public void init() {        entityManagerFactory = Persistence.createEntityManagerFactory("EmployeeService") ;        entityManager = entityManagerFactory.createEntityManager() ;        transaction = entityManager.getTransaction() ;        employeeService = new EmployeeService(entityManager) ;    }        @After    public void destory(){        entityManager.close();        entityManagerFactory.close();    }    }

  /**     * 创建测试     */    @Test    public void createTest() {        transaction.begin();        Employee employee = employeeService.createEmployee(158, "watchfree", 35000);        transaction.commit();        System.out.println(employee.toString());    }

/**     * find     */    @Test    public void findTest() {      Employee employee = employeeService.findEmployee(158);      System.out.println(employee.toString());    }

/**     * 查詢所有     * @return     */    public List<Employee> findAllEmployees() {        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e",Employee.class);        return query.getResultList();    }

/**     * 更新測試     */    @Test    public void updateTest (){        transaction.begin();        Employee employee = employeeService.raiseEmployeeSalary(158, 1000);        transaction.commit();        System.out.println(employee);    }

/**     * 刪除測試     */    @Test    public void deleteTest() {        transaction.begin();        employeeService.removeEmployee(158);        transaction.commit();        System.out.println("remove Employee 158");    }