mybatis框架入门

 第一步写配置文件

 /logback.xml和mybatis-config.xml和UserMepper.xml的配置文件

//logback.xml的配置文件




[%leve]%blue(%d{HH:mm:ss.SSS})%cyan([%thread])%boldGreen(%logger{15})-%msg%n





    

//mybatis-config.xml配置文件



    
        
            
            
                
                
                
                
                
            
        
    
    
        
        
    

//UserMepper.xml的配置文件




    
        select * from tb_user;
    

2.在java里新建一个包取一个名字叫user的类文件,然后写入toString和set和get方法,注:idea的快捷键是Ait+ins

package com.wwdz.pojo;

public class User {
    private Integer id;
    private String username;
    private String password;
    private String gender;
    private String addr;

   public Integer getId() {
      return id;
   }

   public void setId(Integer id) {
      this.id = id;
   }

   public String getUsername() {
      return username;
   }

   public void setUsername(String username) {
      this.username = username;
   }

   public String getPassword() {
      return password;
   }

   public void setPassword(String password) {
      this.password = password;
   }

   public String getGender() {
      return gender;
   }

   public void setGender(String gender) {
      this.gender = gender;
   }

   public String getAddr() {
      return addr;
   }

   public void setAddr(String addr) {
      this.addr = addr;
   }

   @Override
   public String toString() {
      return "pojo{" +
              "id=" + id +
              ", username='" + username + ''' +
              ", password='" + password + ''' +
              ", gender='" + gender + ''' +
              ", addr='" + addr + ''' +
              '}';
   }
}

3.在这个java里新建一个叫mybatisdemo的类文件

import com.wwdz.pojo.User;
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;
import java.util.List;

public class MybatisDemo {
    //1加载mybatis的核心配置文件.获取sqlSessionfactory
    public static void main(String[] args) throws IOException {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.h获取sqlSession对象用他来执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.执行sql
        List users = sqlSession.selectList("test.selectAll");
        System.out.println(users);
        //释放资源
        sqlSession.close();
    }
}

4.要在MySQL里先建好表

 代码在下面

Create database mybatis;
use mybatis;
drop table if exists tb_user;
create table tb_user(
id int primary key  auto_increment,
username varchar(20),
password varchar(20),
gender char(2),
addr varchar(30)
);
insert into tb_user values(1,'汪','123','男','四川');
insert into tb_user values(2,'瞧','123','男','四川');
insert into tb_user values(3,'刘','123','男','四川');