mybatis(1)

mybatis-config.xml

<?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>
    
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <! - configuration data source
              Four connection properties need to configure the database
       -->
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
       <-! Database url ->
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
      </dataSource>
    </environment>
  </environments>
  
  
  <!-- 
      mappers tag to configure the profile to sql mapper
   -->
  <mappers>
      <-! Mapper introduced a configuration file sql statement
              resource properties you want to configure the profile path introduced
              
       -->
    <mapper resource="com/pojo/UserMapper.xml"/> 
  </mappers>
</configuration>

log4j.properties

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

User.java is to use variable (and the corresponding fields in the database)

    private Integer id;
    private String lastName;
    private Integer sex;

UserMapper.xml

<?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">
<!-- 
    namespace name space (usually there are two values)
        A: javaBean corresponding full class name
        II: Full class name corresponding interface Mapper
 -->
<mapper namespace="com.pojo.User">    
    <!-- 
        select tag indicates the select statement
            id is currently the sql statement to configure a unique identifier
            After resultType select query is executed, each row corresponding to record the full class name of the object javaBean
            
        # {id} in mybatis bit symbol midpoint ?
     -->
     
     
  <select id="selectUserById" resultType="com.pojo.User">  
    select id,last_name lastName,sex from t_user where id = #{id}
  </select>
</mapper>

test

@Test
    public void test2() throws Exception
    {
        InputStream is=Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(is);
        //获取session对象
        SqlSession ss=sqlSessionFactory.openSession();
        System.out.println(2);
        try {
            User user = ss.selectOne("com.pojo.User.selectUserById", 1);
            System.out.println(user);
        } finally {
            // TODO: handle finally clause
            ss.close();
        }
    }