package cn.ycx.entity;

import javax.persistence.Entity;

import javax.persistence.Id;

@Entity

public 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;

    }

    @Override

    public String toString() {

        return "Employee [id=" + id + ", name=" + name + ", salary=" + salary + "]";

    }

}

package cn.ycx.service;

import javax.persistence.EntityManager;

import cn.ycx.entity.Employee;

public class EmployeeService {

    private EntityManager em;

    public EmployeeService (EntityManager em) {

        this.em = em;

    }

    public Employee createEmployee(int id, String name, long salary) {

        Employee employee = new Employee();

        employee.setId(id);

        employee.setName(name);

        employee.setSalary(salary);

        em.persist(employee);

        return employee;

    }

}

package cn.ycx.test;

import javax.persistence.EntityManager;

import javax.persistence.EntityManagerFactory;

import javax.persistence.EntityTransaction;

import javax.persistence.Persistence;

import cn.ycx.entity.Employee;

import cn.ycx.service.EmployeeService;

public class EmployeeTest {

    public static void main(String[] args) {

        EntityManagerFactory emf = Persistence.createEntityManagerFactory("EmployeeServiceUnit");

        EntityManager em = emf.createEntityManager();

        EmployeeService service = new EmployeeService(em);

        EntityTransaction et = em.getTransaction();

        et.begin();

        Employee employee = service.createEmployee(1, "tom", 5000);

        et.commit();

        System.out.println(employee);

    }

}

<?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="EmployeeServiceUnit" transaction-type="RESOURCE_LOCAL">

        <class>cn.ycx.entity.Employee</class>

        <properties>

            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>

            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/ycxfw"/>

            <property name="javax.persistence.jdbc.user" value="root"/>

            <property name="javax.persistence.jdbc.password" value="123456"/>

        </properties>

    </persistence-unit>

</persistence>