MyBatis 实现基本CRUD操作

在上一篇中已经讲了，基本的配置，那么在这里就不在多说了，直接上源码。

1.myBatis工具类

package com.maya.util;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class SqlSessionFactoryUtil {
    
    private static SqlSessionFactory sqlSessionFactory;
    
    public static SqlSessionFactory getsqlSessionFactory(){
        if(sqlSessionFactory==null){
            InputStream inputStream=null;
            try {
                inputStream=Resources.getResourceAsStream("mybatis-config.xml");//读取配置文件
                sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sqlSessionFactory;
    }
    
    public static SqlSession openSession(){
        return getsqlSessionFactory().openSession();
    }
    
}

2.Mapper接口

package com.maya.mappers;
import java.util.List;
import java.util.Map;

import com.maya.model.Student;

public interface StudentMapper {
    //添加
    public int add(Student student);
    //修改
    public int update(Student student);
    //删除
    public int delete(int id);
    //查询全部
    public List<Student> findAll();
    //查询单个
    public Student getOneById(int id);
    //根据条件查询
    public List<Student> findWhere(Map<String, Object>param);
}

3.映射文件

<?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.maya.mappers.StudentMapper">

    <!-- 通常当查询结果是一个集合的话，我们都会在这里定义一个resultMap,用来给下面的方法引用 -->
    <resultMap type="Student" id="StudentResult"><!-- type就是集合中的类型，id随便你怎么起 -->
        <id property="id" column="id"></id><!-- property是类的属性名，对应，column是数据库的字段名 -->
        <result property="name" column="name" />
        <result property="age" column="age" />
    </resultMap>

    <insert id="add" parameterType="Student"  ><!-- id方法名，parameterType别名,如果不谢别名就要写完成限定名 -->
        insert into student values(null,#{name},#{age})<!-- 在这里写语句 -->
    </insert>
    
    <update id="update" parameterType="Student">
        update student set name=#{name}, age=#{age} where id=#{id}
    </update>
    
    <delete id="delete" parameterType="int">
        delete from student where id=#{id}
    </delete>
    
    <select id="getOneById" parameterType="int" resultType="Student">
        select * from student where id=#{id}
    </select>
        
        
    <!-- <select id="findAll" resultType="Student">
        select * from student
    </select> -->
    <!-- 因为在上面我们定义了一个resultMap所以在这里我们就可以写成下面的方式，当然这两种方式都是可以的 -->
    <select id="findAll" resultMap="StudentResult">
        select * from student
    </select>
    
    
    <!-- <select id="findWhere" parameterType="Map" resultType="Student">
        select * from student where name like #{a1}
    </select> -->
    <select id="findWhere" parameterType="Map" resultMap="StudentResult">
        select * from student where name like #{a1} and age=#{a2}
    </select>

</mapper> 

4.junit测试

package com.maya.service;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.maya.mappers.StudentMapper;
import com.maya.model.Student;
import com.maya.util.SqlSessionFactoryUtil;

public class JunitTest {
    private static Logger logger=Logger.getLogger(JunitTest.class);
    private SqlSession sqlSession=null;
    private StudentMapper studentMapper=null;
    
    /**
     * 测试方法之前调用
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        sqlSession=SqlSessionFactoryUtil.openSession();
        studentMapper=sqlSession.getMapper(StudentMapper.class);
    }
    
    /**
     * 测试方法之后调用
     * @throws Exception
     */
    @After
    public void tearDown() throws Exception {
        sqlSession.close();
    }

    @Test
    public void testAdd() {
        logger.info("添加学生");
        Student s=new Student("哈哈哈哈",16);
        studentMapper.add(s);
        sqlSession.commit();
    }
    
    @Test
    public void testUpdate() {
        logger.info("修改学生");
        Student s=new Student(7,"哈哈123",19);
        studentMapper.update(s);
        sqlSession.commit();
    }
    
    @Test
    public void testDelete() {
        logger.info("删除学生");
        studentMapper.delete(4);
        sqlSession.commit();
    }
    
    @Test
    public void testGetOneById() {
        logger.info("查找单个学生");
        Student s=studentMapper.getOneById(6);     
        System.out.println(s.getName());    
    }
    
    @Test
    public void testFindAll() {
        logger.info("查找全部学生");
        List<Student> list=studentMapper.findAll();
        for(Student s:list){
            System.out.println(s.getName());
        }        
    }
    
    @Test
    public void testFindWhere() {
        logger.info("根据条件查找学生");
        Map<String, Object> param=new HashMap<String,Object>();
        param.put("a1", "%哈%");
        param.put("a2", 19);
        List<Student> list=studentMapper.findWhere(param);
        for(Student s:list){
            System.out.println(s.getName());
        }        
    }

}