mybatis--CURD操作

Posted 2021-03-06 Jason–json

mybatis基本的增删查改操作

1.编写session工具类

package com.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;

public class MybatisUtils {
    private static SqlSession session;
    private static SqlSessionFactory factory;

    static {
        InputStream is= null;
        try {
            is = Resources.getResourceAsStream("mybatis.xml");
            SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
            factory = builder.build(is);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSession(){
        session=factory.openSession();
        return session;
    }

}

 

2.映射配置文件

<?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.dao.UserMapper">
    <select id="findAll"  resultType="com.bean.User">
        select * from test_user;
    </select>

    <insert id="save" parameterType="com.bean.User" >
        INSERT INTO test_user(u_name,u_lovel) VALUES(#{uName},#{uLovel})
    </insert>

    <select id="find"  resultType="com.bean.User" parameterType="java.lang.Integer">
        select * from test_user where u_id=#{uId};
    </select>
    
    <update id="updateUser" parameterType="com.bean.User">
        update test_user set u_lovel = #{uLovel},u_name=#{uName} where u_id=#{uId};
    </update>

    <select id="findbyName"  resultType="com.bean.User" parameterType="java.lang.String">
        select * from test_user where u_name like #{uName};
    </select>

    <select id="findbyName2"  resultType="com.bean.User" parameterType="java.lang.String">
        select * from test_user where u_name like ‘%‘{$uName} ‘%‘;
    </select>


</mapper>

3.dao层接口类

import com.bean.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface UserMapper {

    //@Select(" select * from test_user")
    List<User> findAll();

    int save(User user);

    User find(Integer i);

    int updateUser(User user);

    List<User> findbyName(String s);

    List<User> findbyName2(String s);

}

4.测试类

package com;

import com.bean.User;
import com.dao.UserMapper;
import com.utils.MybatisUtils;
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.InputStream;
import java.util.List;

public class MybaitsTest01 {

    @Test
    public void m1() throws Exception{
        //1.读取主配置文件
        InputStream is= Resources.getResourceAsStream("mybatis.xml");
        //2.创建SessionFactory工厂
        SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(is);
        //3.使用工厂得到SQLSession对象
        SqlSession session = factory.openSession();
        //4.使用SqlSession创建dao接口的代理对象
        UserMapper mapper = session.getMapper(UserMapper.class);
        //5.使用带库对象执行方法
        List<User> all = mapper.findAll();
        for (User user : all) {
            System.out.println(user);
        }
        //6.释放资源
        session.close();
        is.close();
    }


    //编写工具类查询所有
    @Test
    public void m2(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        List<User> all = mapper.findAll();
        for (User user : all) {
            System.out.println(user);
        }
        session.close();
    }

    //保存操作
    @Test
    public void m3(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        User user1 = new User();
        user1.setuLovel("谦虚");
        user1.setuName("周瑜");
        int save = mapper.save(user1);
        if (save>0){
            System.out.println("User保存成功");
        }else{
            System.out.println("User保存失败");
        }
        session.commit();
        session.close();
    }

    //查询单个操作
    @Test
    public void m4(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        User user = mapper.find(1);
        System.out.println(user);
        session.close();
    }

    //更新测试
    @Test
    public void m5(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        User user = mapper.find(1);
        user.setuLovel("111");
        int i = mapper.updateUser(user);
        if (i>0){
            System.out.println("更新成功");
        }else{
            System.out.println("更新失败");
        }
        session.commit();
        session.close();
    }

    //模糊查询
    @Test
    public void m6(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
       // List<User> users = mapper.findbyName("%角%");
        List<User> users = mapper.findbyName("角");
        for (User user : users) {
            System.out.println(user);
        }

        session.commit();
        session.close();
    }

}