mybatis入门---mybatis配置文件与映射文件详解

￡神魔★判官ぃ 2024-02-18 23:43 69阅读 0赞

## mybatis配置文件 mybatis-config.xml ##

通常放在src根目录下

<?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"></properties>
    
    
    
    
    
    
    <typeAliases>
    
    
      <package name="pojo"/>
    </typeAliases>
    
    
    
      <environments default="development">
        <environment id="development">
        
        	
          <transactionManager type="JDBC"/>
          
          
          <dataSource type="POOLED">
          
            
            <property name="driver" value="${jdbc.driver}"/>
            <property name="url" value="${jdbc.url}"/>
            <property name="username" value="${jdbc.username}"/>
            <property name="password" value="${jdbc.password}"/>
          </dataSource>
        </environment>
      </environments>
      
      
    
    
      <mappers>
    
    
    <package name="mapper"/>
      </mappers>
    </configuration>

## mybatis映射文件 BlogMapper.xml ##

通常放在mapper包下，与mapper接口类形成映射

<?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="mapper.BlogMapper">
    
     
    
    
    
    
     
     
    
       
      <select id="selectBlog" parameterType="int" resultType="Blog">
        select * from Blog where id = #{id}
      </select>
      
      
      
      
    </mapper>

mapper接口类BlogMapper.java

package mapper;
    
    import pojo.Blog;
    
    public interface BlogMapper {
    
    	//这里的参数Integer id要与映射文件BlogMapper.xml中的parameterType="int"相对应
    	Blog selectBlog(Integer id);
    	
    }