MyBatis的xml+接口方式实现crud功能

Mybatis的xml+接口方式实现crud功能

1. User.java

   package com.qfedu.pojo;
   
   import lombok.AllArgsConstructor;
   import lombok.Data;
   import lombok.NoArgsConstructor;
   
   @Data
   @NoArgsConstructor
   @AllArgsConstructor
   public class User {
   
       private int uid;
       private String username;
       private String password;
       private int age;
       private String addr;
   }
   

2. IUserDao.java

   package com.qfedu.dao;
   
   import com.qfedu.pojo.User;
   
   import java.util.List;
   
   public interface IUserDao {
   
       /**
        *  查询所有的User对象
        * @return User对象的列表
        */
       List<User> getAllUsers();
   
       /**
        * 新增一个User对象
        * @param u 要新增的用户对象
        * @return 受影响的行数
        */
       int saveUser(User u);
   }
   

3. 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">
   
   <!--
       第二种实现mybatis的方式为：接口+xml方式
       这种方式有特别的要求
           1.  namespace必须是接口的全路径
           2.  每个节点的id必须是接口中的方法名
           3.  该接口中的方法不允许重载，否则namespace+id将不唯一
           4.  注意该接口中的增删改的方法的返回值，最好使用int
   -->
   <mapper namespace="com.qfedu.dao.IUserDao">
       
       <!--
           ID为接口中的方法名
       -->
       <select id="getAllUsers" resultType="User">
         select * from user
       </select>
   
       <insert id="saveUser" >
           insert into user values(null, #{username}, #{password}, #{age}, #{addr})
       </insert>
   
       <update id="updateUser">
           update user set username = #{username}, password =#{password}, age=#{age}, addr = #{addr} where uid = #{uid}
       </update>
   </mapper>
   

4. SessionUtils.java

   package com.qfedu.util;
   
   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;
   
   public class SessionUtils {
   
       private static SqlSession mSession = null;
       private static SqlSessionFactory mFactory = null;
   
       static {
           try {
               mFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml"));
           } catch (IOException e) {
               e.printStackTrace();
           }
       }
   
   
       /**
        * 获取SqlSession对象
        * @return
        */
       public static SqlSession getSession(){
   
           mSession = mFactory.openSession(true);
   
           return mSession;
       }
   
       /**
        * 关闭SqlSession对象
        * @param session 要关闭的SqlSession对象
        */
       public static void closeSession(SqlSession session){
           if(session != null){
               session.close();
               session = null;
           }
       }
   }
   

5. Mybatis.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">
   
   <!--
       该配置文件中包含一个configuration节点
           里面有配置信息 分别是环境和映射
           　其中环境里有datasource，里面有我们熟悉的连接数据库的四个字符串
   -->
   <configuration>
   
       <!--
           引入db的配置文件信息，后面用到的四个连接字符串就可以直接使用 ${}的方式来动态引入
       -->
       <properties resource="db.properties">
       </properties>
   
       <!--
           给当前mybatis项目添加日志功能，该STDOUT_LOGGING值的好处是不用添加第三方jar包就可以有日志的输出
       -->
       <settings>
           <setting name="logImpl" value="STDOUT_LOGGING"/>
       </settings>
   
       <typeAliases>
           <!--<typeAlias type="com.qfedu.pojo.Order" alias="abc" />-->
           <package name="com.qfedu.pojo" />
       </typeAliases>
   
       <environments default="development">
           <environment id="development">
               <transactionManager type="JDBC"/>
               <dataSource type="POOLED">
                   <property name="driver" value="${driver}"/>
                   <property name="url" value="${url}"/>
                   <property name="username" value="${user}"/>
                   <property name="password" value="${pass}"/>
               </dataSource>
           </environment>
       </environments>
       <mappers>
           <mapper resource="com/qfedu/dao/UserMapper.xml"/>
       </mappers>
   </configuration>
   

6. TestUser.java

   package com.qfedu.pojo;
   
   import org.junit.Test;
   
   public class TestUser {
   
       @Test
       public void testUser(){
   
           User u = new User();
   
           u.setUid(1);
           u.setUsername("chenggang");
           u.setPassword("888888");
           u.setAddr("shenzhen");
           u.setAge(18);
   
           System.out.println(u);
       }
   }
   

7. TestUserDao.java

   package com.qfedu.pojo;
   
   import com.qfedu.dao.IUserDao;
   import com.qfedu.util.SessionUtils;
   import org.apache.ibatis.session.SqlSession;
   import org.junit.After;
   import org.junit.Before;
   import org.junit.Test;
   
   import java.util.List;
   
   public class TestUserDao {
   
       private SqlSession session = null;
   
       @Before
       public void setUp(){
   
           session = SessionUtils.getSession();
       }
   
       @After
       public void tearDown(){
           SessionUtils.closeSession(session);
       }
   
       @Test
       public void testGetAllUsers(){
           IUserDao mapper = session.getMapper(IUserDao.class);
   
           List<User> users = mapper.getAllUsers();
   
           for (User u : users) {
               System.out.println(u);
           }
       }
   
       @Test
       public void testSaveUser(){
           IUserDao userDao = session.getMapper(IUserDao.class);
   
           User u = new User(17, "liuchang", "888888", 20, "guangzhou");
           int result = userDao.saveUser(u);
           System.out.println(result);
       }
   }