Mybatis入门

Mybatis环境搭建步骤

Mybatis环境搭建步骤
1.先创建Maven项目(页面结构如下)，选择项目JDK1.8

2.创建完成，在pom.xml中导入依赖

    4.0.0
    org.example
    Mybatis1
    pom
    1.0-SNAPSHOT
    
        Mybatis-01
    
    
    
        
            
                src/main/resources
                
                    ***.xml
                
                true
            
            
                src/main/java
                
                    ***.xml
                
                true
            
        
    
    
    
        
            mysql
            mysql-connector-java
            5.1.46
        
        
            org.mybatis
            mybatis
            3.5.2
        
        
            junit
            junit
            4.12
        
    
    
        8
        8
    

3.在src下新建文件夹pojo，编写User实体类

package com.yzh.pojo;
public class User
{
    private int id;
    private String name;
    private  String pwd;

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPwd() {
        return pwd;
    }
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + ''' +
                ", pwd='" + pwd + ''' +
                '}';
    }
}

4.在dao包编写持久层接口 UserDao
UserDao 接口就是我们的持久层接口（也可以写成 UserDao 或者 UserMapper）,具体代码如下：

package com.yzh.dao;

import com.yzh.pojo.User;

import java.util.List;

public interface UserDao {
    List getUserList();
}

5.在dao编写持久层接口的映射文件 UserMapper.xml

   
       select  * from mybatis.user;
   

6.编写 Mybatis-config.xml 配置文件

7.编写Mybatis工具封装类

package com.yzh.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 SqlSessionFactory sqlSessionFactory;
    static {
        String resource = "mybatis-config.xml";
        try {
            //第一步获取SqlSessionFactory对象
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    //获取实例
    public  static SqlSession getSqlSession(){
       SqlSession sqlSession=sqlSessionFactory.openSession();
       return sqlSession;
    }
}

8.编写测试类

package com.yzh.dao;


import com.yzh.pojo.User;
import com.yzh.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserDaoTest {
    @Test
    public  void test(){
        SqlSession sqlSession= MybatisUtils.getSqlSession();
      UserDao mapper=  sqlSession.getMapper(UserDao.class);
      List userList= mapper.getUserList();
        for (User user : userList) {
            System.out.println(user);
        }
    }
}

到此处算是搭建完毕了（新人入门还不太熟练~~~）
注意踩坑的地方:在pom.xml文件中要配置过滤.XML文件的代码，否则会报错
报错如下图