MyBatis配置文件增删查改解析及手动映射操作

你的名字 2023-03-13 12:23 10阅读 0赞

### 主配置文件 mybatis-config.xml ###

在项目的 src （类路径 classpath） 下面创建 配置文件 mybatis-config.xml  
具体配置可参考mybatis的官方文档

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration
      PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
      "http://mybatis.org/dtd/mybatis-3-config.dtd">
    
      
      
      
    <configuration>
    
    	
    	<properties resource="db.properties"/>
    	
    	
    	<settings> 
    		
    		 <setting name="mapUnderscoreToCamelCase" value="true"/> 
    		
    	 </settings>
    
    	
    		<typeAliases>
    			
    			<typeAlias type="com.ywq.mybatis.pojo.User" alias="User"/>
    			
    			
    			<package name="com.ywq.mybatis.pojo"/>
    		</typeAliases>
    	
    	
      <environments default="mysql">
      
      	
        <environment id="mysql">
        
        	
          <transactionManager type="JDBC"/>
          
          
          <dataSource type="POOLED">
          
         	 
            <property name="driver" value="${driverClassName}"/>
            
            <property name="url" value="${url}"/>
            
            <property name="username" value="${username}"/>
            
            <property name="password" value="${password}"/>
            
          </dataSource>
        </environment>
      </environments>
      
      
      <mappers>
        <mapper resource="com/ywq/mybatis/mapper/UserMapper.xml"/>
      </mappers>
    </configuration>

## 获取Session代码块文件 ##

package com.ywq.mybatis.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 MyBatisUtils {
        
    	private MyBatisUtils() {
        }
    	
    	private static SqlSessionFactory factory;
    	
    	//只运行一次
    	static{
        
    		String resource = "mybatis-config.xml";
    		
    		try(InputStream	inputStream = Resources.getResourceAsStream(resource);){
        
    			 factory = new SqlSessionFactoryBuilder().build(inputStream);
    		} catch (IOException e) {
        
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    	
    	//获得openSession
    	public static SqlSession openSession() {
        
    		SqlSession openSession = factory.openSession();
    		return openSession;
    	}
    	
    	
    }

## pojo类代码 ##

package com.ywq.mybatis.pojo;
    
    public class User {
        
    	private Integer uId ;
    	private String uName;
    	private String uPassword;
    	private Integer uAge;
    	
    	
    	public User() {
        
    		super();
    	}
    	public User(Integer uId, String uName, String uPassword, Integer uAge) {
        
    		super();
    		this.uId = uId;
    		this.uName = uName;
    		this.uPassword = uPassword;
    		this.uAge = uAge;
    	}
    	public Integer getuId() {
        
    		return uId;
    	}
    	public void setuId(Integer uId) {
        
    		this.uId = uId;
    	}
    	public String getuName() {
        
    		return uName;
    	}
    	public void setuName(String uName) {
        
    		this.uName = uName;
    	}
    	public String getuPassword() {
        
    		return uPassword;
    	}
    	public void setuPassword(String uPassword) {
        
    		this.uPassword = uPassword;
    	}
    	public Integer getuAge() {
        
    		return uAge;
    	}
    	public void setuAge(Integer uAge) {
        
    		this.uAge = uAge;
    	}
    	@Override
    	public String toString() {
        
    		return "User [uId=" + uId + ", uName=" + uName + ", uPassword=" + uPassword + ", uAge=" + uAge + "]";
    	}
    	
    	
    }

## Mapper接口 ##

package com.ywq.mybatis.mapper;
    
    import java.util.List;
    
    import com.ywq.mybatis.pojo.User;
    
    
    /*
     *mybatis的映射接口
     * */
    public interface UserMapper {
        
    		
    	// DML ：增删改
    	
    	int insert(User user);
    	
    	int deleteByPrimaryKey(Integer id);
    	
    	int updateByPrimaryKey(User user);
    	
    	//DQL : 查询
    	User selectByPrimaryKey(Integer id);
    	
    	List<User> selectLits();
    }

## Mapper.xml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.ywq.mybatis.mapper.UserMapper">
      
      
      
      <insert id="insert" parameterType="User"
      keyColumn="id" keyProperty="uId" useGeneratedKeys="true" 
      >
      
    	insert into user (Name,Password,Age)values(#{
        uName},#{
        uPassword},#{
        uAge})
      </insert>
      
      
      <update id="updateByPrimaryKey" parameterType="User">
    	update user set name = #{
        uName},password=#{
        uPassword},age=#{
        uAge} where id =#{
        uId}  	
      </update>
      
      
      <delete id="deleteByPrimaryKey" parameterType="Integer">
        
      	delete from user where id = #{
        id}
      </delete>
      
      
      
      <select id="selectByPrimaryKey" parameterType="Integer" resultMap="user_map">
      select id u_id,name u_name,password u_password,age u_age from user where id = #{
        id}
      </select>
      
       
      	<resultMap type="com.ywq.mybatis.pojo.User" id="user_map">
      	
      	
      	<id column="u_id" property="uId" javaType="Integer" jdbcType="INTEGER" />
      	
      	<result column="u_name" property="uName" javaType="String" jdbcType="VARCHAR"/>
      	<result column="u_password" property="uPassword" />
      	<result column="u_age" property="uAge" />
      	</resultMap>
      
      
      
      
      
      
      <select id="selectLits" resultType="user">
      	select id u_id,name u_name,password u_password,age u_age from user
      </select>
      
    </mapper>

## 测试代码 ##

package com.ywq.mybatis.test;
    
    import static org.junit.Assert.*;
    
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    import org.junit.Test;
    
    import com.ywq.mybatis.mapper.UserMapper;
    import com.ywq.mybatis.pojo.User;
    import com.ywq.mybatis.util.MyBatisUtils;
    
    public class MyBatisTest {
        
    	
    	@Test
    	public void testInert() throws Exception {
        
    		
    		//1.创建SqlSession对象
    		SqlSession session = MyBatisUtils.openSession();
    		//2.创建UserMapper映射接口的动态代理对象
    		UserMapper userMapper = session.getMapper(UserMapper.class);
    		System.out.println(userMapper.getClass().getName());
    		
    		//3.执行insert方法
    		User user = new User(null, "jocn", "2020", 33);
    		
    		int row = userMapper.insert(user);
    		System.out.println("受影响的行数："+row);
    		//4.MyBatis默认需要手动提交事务
    		session.commit();
    		
    		//5.关闭session（释放资源）
    		session.close();
    	}
    	
    	@Test
    	public void testUpdate() throws Exception {
        
    		
    		//1.创建SqlSession对象
    		SqlSession session = MyBatisUtils.openSession();
    		
    		//2.创建UserMapper映射接口的动态对立对象
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		
    		//3.执行修改方法
    		
    		User user = new User(6, "fg邦", "5161", 25);
    		int row = mapper.updateByPrimaryKey(user);
    		
    		System.out.println("受影响行数"+row);
    		
    		//4.MyBatis默认需要手动提交事务
    		session.commit();
    		
    		//5.关闭session（释放资源）
    		session.close();
    		
    	}
    	
    	@Test
    	public void testDelete() throws Exception {
        
    		
    		//1.创建SqlSession对象
    		SqlSession session = MyBatisUtils.openSession();
    		
    		//2.创建UserMapper映射接口的动态对立对象
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		
    		//3.执行删除方法
    		
    		int row = mapper.deleteByPrimaryKey(10);
    		
    		System.out.println("受影响行数"+row);
    		
    		//4.MyBatis默认需要手动提交事务
    		session.commit();
    		
    		//5.关闭session（释放资源）
    		session.close();
    		
    	}
    	
    	@Test
    	public void testSelectOne() throws Exception {
        
    		
    		//1.创建SqlSession对象
    		SqlSession session = MyBatisUtils.openSession();
    		
    		//2.创建UserMapper映射接口的动态对立对象
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		
    		//3.执行单行查询方法
    		
    		User user = mapper.selectByPrimaryKey(5);
    		
    		System.out.println(user);
    		
    		//4.MyBatis默认需要手动提交事务
    		session.commit();
    		
    		//5.关闭session（释放资源）
    		session.close();
    		
    	}
    	
    	@Test
    	public void testSelectList() throws Exception {
        
    		
    		//1.创建SqlSession对象
    		SqlSession session = MyBatisUtils.openSession();
    		
    		//2.创建UserMapper映射接口的动态对立对象
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		
    		//3.执行多行查询方法
    		
    		List<User> users = mapper.selectLits();
    		for (User user : users) {
        
    			System.out.println(user);
    			
    		}
    		
    		//4.MyBatis默认需要手动提交事务
    		session.commit();
    		
    		//5.关闭session（释放资源）
    		session.close();
    		
    	}
    }