在【Mybatis】（一）第一個mybatis例項中，已經初步搭建了 MyBatis 框架，實現了查詢所有記錄的功能，並用 JUnit 進行了單元測試

接下來我們將在此基礎上使用基於XML的方式對錶進行CRUD操作

1、定義EmployeeMapper.xml配置檔案

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 


<mapper namespace="com.lhk.mybatis.dao.EmployeeMapper">

    <!--
    namespace:名稱空間;指定為介面的全類名
    id：唯一標識，此時與介面的方法名相對應（getEmpById）
    resultType：返回值型別
    #{id}：從傳遞過來的引數中取出id值
    public Employee getEmpById(Integer id);
     -->

    <!--根據id查詢Employee的所有資訊-->
    <select id
 
="getEmpById" resultType="com.lhk.mybatis.bean.Employee">
        select id,last_name lastName,email,gender from tb1_employee where id = #{id}
    </select>

    <!--新增Employee資訊-->
    <insert id="addEmp" parameterType="com.lhk.mybatis.bean.Employee">
        insert into tb1_employee(last_name,email,gender)
        values (#{lastName},#{email},#{gender})
    </insert
 
>

    <!--根據id修改Employee的資訊-->
    <update id="updateEmp" parameterType="com.lhk.mybatis.bean.Employee">
        update tb1_employee
        set last_name=#{lastName},email=#{email},gender=#{gender}
        where id=#{id}
    </update>

    <!--根據id刪除Employee-->
    <delete id="deleteEmpById" parameterType="com.lhk.mybatis.bean.Employee">
        delete from tb1_employee where id=#{id}
    </delete>
</mapper>

2、定義EmployeeMapper.java介面

package com.lhk.mybatis.dao;

import com.lhk.mybatis.bean.Employee;

public interface EmployeeMapper {

   public Employee getEmpById(Integer id);

    public void addEmp(Employee employee);

    public void updateEmp(Employee employee);

    public void deleteEmpById(Employee employee);

}

3、單元測試類MybatisPlusTest.java

package com.lhk.mybatis.test;

import com.lhk.mybatis.bean.Employee;
import com.lhk.mybatis.dao.*;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author lhk
 * @create 2018-09-08 10:13
 */
public class MybatisTest {

    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "conf/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(inputStream);
    }

    @Test
    public void testAdd() throws IOException {
        SqlSessionFactory SqlSessionFactory = getSqlSessionFactory();

        // 獲取到的sqlSession不會自動提交資料
        SqlSession openSession = SqlSessionFactory.openSession();

        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            Employee employee = new Employee(15, "lhk", "[email protected]", "1");
            mapper.addEmp(employee); // 1、測試新增
            openSession.commit();  // 手動提交資料
        } finally {
            openSession.close();
        }
    }

    @Test
    public void testUpdate() throws IOException {
        SqlSessionFactory SqlSessionFactory = getSqlSessionFactory();

        // 獲取到的sqlSession不會自動提交資料
        SqlSession openSession = SqlSessionFactory.openSession();

        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            Employee employee = new Employee(15, "lll", "[email protected]", "1");

            mapper.updateEmp(employee);  // 2、測試修改
            openSession.commit();   // 手動提交資料
        } finally {
            openSession.close();
        }
    }

    @Test
    public void testSelect() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();

        SqlSession openSession = sqlSessionFactory.openSession();
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            Employee employee = mapper.getEmpById(2); // 2、測試查詢
            System.out.println(employee);
        } finally {
            openSession.close();
        }
    }

    @Test
    public void testDelete() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();

        SqlSession openSession = sqlSessionFactory.openSession();
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            Employee employee = new Employee(15, "lhk", "[email protected]", "1");
            mapper.deleteEmpById(employee); // 測試刪除
            openSession.commit();  // 手動提交資料
        } finally {
            openSession.close();
        }
    }
}