Mybatis(二)入门程序通过id查找用户、模糊查找用户、添加用户、删除用户

根据下图myBatis的架构，创建一个使用MyBatis的工程。

一、配置MyBatis 环境（如图）

1、sqlMapConfig.xml

首先，导入jar包（上图右边）并加载路径，然后在目录下创建一个xml文件 sqlMapConfig.xml , 并添加以下配置代码, 这就是上图架构中的第一步配置mybatis环境,

<?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">
			<!-- 使用jdbc事务管理 -->
			<transactionManager type="JDBC" />
			<!-- 数据库连接池 -->
			<dataSource type="POOLED">
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<property name="url"
					value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8" />
				<property name="username" value="root" />
				<property name="password" value="root" />
			</dataSource>
		</environment>
	</environments>

2. 配置Mappern.xml

在src目录下创建一个包叫sqlmap，用来放mappern.xml，然后在在该包下面创建一个User.xml 文件，并输入下面代码

<?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：命名空间，用于隔离sql，还有一个很重要的作用，后面会讲 -->
<mapper namespace="test">
   
   //通过id查询用户
   <select id="findUserById" parameterType ="Integer" resultType="mybatis.pojo.User">
      select * from user where id = #{v}
   </select>
   
   //模糊查询用户
    <select id="findUserByUsername" parameterType ="String" resultType="mybatis.pojo.User">
      select * from user where username like '%${value}%'
   </select>

  
    //添加用户

<insert id="insertUser" parameterType ="mybatis.pojo.User">
insert into user (username,birthday,address,sex)
values(#{username},#{birthday},#{address},#{sex})
</insert>

// 更新用户信息

<update id="updateUserById" parameterType="mybatis.pojo.User">
update user
set username = #{username},sex = #{sex},birthday = #{birthday},address = #{address}
where id = #{id}
</update>

//通过id删除用户

<delete id="deleteUserById" parameterType="Integer">
delete from user
where id = #{vvvvv}
</delete>

</mapper>

3. 然后在src目录下创建log4j.properties用来输出日志，并输入以下信息

# 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

4、在src下创建mybatis.pojo包，并创建User类

package mybatis.pojo;
import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {

    private static final long serialVersionUID = 1L;
    private Integer id;
    private String username;
    private String sex;
    private Date birthday;
    private String address;

    public Integer getId() {
        return id;
    }
//......................................省略

二、构造SqlSessionFactory、通过SqlSessionFactory创建sqlSession会话、通过sqlSession操作数据库

1、在src目录下创建测试包testpackage和测试文件TesMybatis 并输入以下package testpackageimport mybatis.pojo.User;

import java.io.InputStream;
import java.util.List;
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 TestMybatis {

    public static void main(String[] args) throws Exception {
        testMybatis();
    }
    
    public static void testMybatis() throws Exception{
        
        //配置mybatis环境配置信息

        String resource = "sqlMapConfig.xml";
        InputStream in =Resources.getResourceAsStream(resource);
     
        //构造SqlSessionFactory(会话工厂)
  
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in); 
       
         
        //通过SqlSessionFactory创建sqlSession会话
  
        SqlSession sqlSession = sqlSessionFactory.openSession();

        /*
        (1)通过用户id查找用户
        */

        User user = sqlSession.selectOne("test.findUserById", "o"); 
        System.out.println(user); 
       
       
        /*
        (2)模糊查询
        */
        List<User> users = sqlSession.selectList("test.findUserByUsername", "J");
        for(User user2: users){
            System.out.println(user2);
        }

        /*
        （3）增加用户
        */

User user3 = new User();
user3.setUsername("Jane");
user3.setBirthday(new Date());
user3.setAddress("MountainView");
user3.setSex("1");
sqlSession.insert("test.insertUser", user3);
sqlSession.commit();

（4）更新用户信息

User user4 = new User();
user4.setId(10);
user4.setUsername("Luo");
user4.setBirthday(new Date());
user4.setAddress("21811");
user4.setSex("1");
sqlSession.update("test.updateUserById", user4);
sqlSession.commit();

（5）删除用户信息

sqlSession.delete("test.deleteUserById", 29);
sqlSession.commit()；

    }

}

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