mybatis实现增删改查

UserDao接口

package dao;

import bean.Cloud;
import bean.Student;
import bean.Teacher;

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

//等价于mapper
public interface UserDao {
    //查询所有信息
    List<Cloud> getCloud();
    //根据id查询
    Cloud queryCloud(int id);
    //添加
    int addUser(Cloud cloud);
    //修改
    int updateById(Cloud cloud);
    //删除
    int delete(int id);
    //用map
    int update1(Map<String,Object> map);

    //模糊查询
    List<Cloud> getUserLike(String value);

    //查询所有学生
    List<Student> getStu();

    //查询老师
    List<Teacher> getTeacher();
}

UserMapper.xml

<?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">
<!--namespace绑定一个Dao/Mapper接口-->
<mapper namespace="dao.UserDao">
    <select id="getCloud" resultType="bean.Cloud">
        select * from caijing
    </select>
<!--    value是模糊查询的参数-->
    <select id="getUserLike" resultType="cloud">
        select * from caijing where word like "%"#{value}"%"
    </select>

    <select id="queryCloud" parameterType="_int" resultType="bean.Cloud">
        select * from caijing where id = #{id}
    </select>
    <insert id="addUser" parameterType="bean.Cloud">
        insert into caijing (id,word,count) values (#{id},#{word},#{count});
    </insert>
    <update id="updateById" parameterType="bean.Cloud">
        update caijing set word = #{word},count = #{count} where id=#{id};
    </update>

    <update id="update1" parameterType="map">
        update caijing set word = #{words} where id=#{userid};
    </update>
    <delete id="delete" parameterType="int">
        delete from caijing where id = #{id};
    </delete>

    <select id="getStu" resultMap="getStuTeacher">
        select * from student;
    </select>

    <resultMap id="getStuTeacher" type="bean.Student">
        <result property="id" column="id"/>
        <result property="name" column="name"/>
<!--        复杂的属性，我们需要单独处理 对象:association 集合:collection-->
        <association property="teacher" column="tid" javaType="Teacher" select="getTeacher"/>
    </resultMap>

    <select id="getTeacher" resultType="bean.Teacher">
        select * from teacher where id = #{id};
    </select>
</mapper>

工具类：

package utils;

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

//sqlSessionFactory对象
public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;

    static {

        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = null;
            inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSqlSession(){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        return  sqlSession;
    }



}

测试类：

package dao;

import bean.Cloud;
import bean.Student;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import utils.MybatisUtils;

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

public class UserDaoTest {
    @Test
    public void test(){
        //1.获取sqlsession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //2.1执行sql
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        List<Cloud> list = mapper.getCloud();
        for (Cloud cloud : list) {
            System.out.println(cloud);
        }
        //关闭sqlsession
        sqlSession.close();
    }
    @Test
    public void query(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        Cloud cloud = mapper.queryCloud(1000);
        System.out.println(cloud);
        sqlSession.close();
    }
    //增删改需要提交事务
    @Test
    public void addUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        Cloud cloud = new Cloud(1001, "天岁", "10");
        int i = mapper.addUser(cloud);
        if (i==1)
            System.out.println("成功");
        else
            System.out.println("失败");
        sqlSession.commit();           //必须提交事务,我以前没写过啊！
        sqlSession.close();

    }
    @Test
    public void update(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        Cloud cloud = new Cloud(1001, "天岁", "11");
        int i = mapper.updateById(cloud);
        if (i==1)
            System.out.println("成功");
        else
            System.out.println("失败");
        sqlSession.commit();           //必须提交事务,我以前没写过啊！
        sqlSession.close();
    }
    @Test
    public void delete(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        int i = mapper.delete(1001);
        if (i==1)
            System.out.println("成功");
        else
            System.out.println("失败");
        sqlSession.commit();
        sqlSession.close();
    }
    @Test
    public void updateTest(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserDao mapper = sqlSession.getMapper(UserDao.class);

        Map<String, Object> map = new HashMap<String,Object>();

        map.put("words","在发展");

        map.put("userid",1);

        int i = mapper.update1(map);

        if (i==1)
            System.out.println("成功");
        else
            System.out.println("失败");
        sqlSession.commit();

        sqlSession.close();

    }
    //模糊查询实例
    @Test
    public void getCloudLike(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserDao mapper = sqlSession.getMapper(UserDao.class);

        List<Cloud> list = mapper.getUserLike("我");

        for (Cloud cloud : list) {
            System.out.println(cloud);
        }

        sqlSession.close();
    }

    //*********************************
    //一对多实例
    @Test
    public void getStu(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserDao mapper = sqlSession.getMapper(UserDao.class);

        List<Student> stu = mapper.getStu();

        for (Student student : stu) {
            System.out.println(student);
        }
        sqlSession.close();
    }
}