MyBatis使用Mapper动态代理

MyBatis使用Mapper动态代理

采用Mapper动态代理方法只需要编写相应的Mapper接口（相当于Dao接口），那么Mybatis框架根据接口定义创建接口的动态代理对象，代理对象的方法体同Dao接口实现类方法。
Mapper接口开发需要遵循以下规范：
1、Mapper.xml文件中的namespace与mapper接口的全类名相同。
2、Mapper接口方法名和Mapper.xml中定义的每个statement的id相同。
3、Mapper接口方法的输入参数类型和mapper.xml中定义的每个sql 的parameterType的类型相同。
4、Mapper接口方法的输出参数类型和mapper.xml中定义的每个sql的resultType的类型相同。

Mybatis框架主要步骤
  1.创建表
  2.创建javabean
  3.创建核心配置文件 mybatis.config.xml
4.创建映射文件 UserMapper.xml
  5.创建代理接口
  6.java测试类增删改查

需要导入mybatis架包和数据库连接架包

mybatis架包可从该网站下载https://github.com/mybatis/mybatis-3/releases

1.数据库为test 表为user_m

2.javabean的四个属性

public class User {

private int id;
   private String useraName;
   private String userAge;
   private String userAddress;

省略get.set方法和无参构造

}

3.核心配置文件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" />
           <dataSource type="POOLED">
               <property name="driver" value="com.mysql.jdbc.Driver" />
               <property name="url" value="jdbc:mysql://localhost:3306/test" /> 数据库名
               <property name="username" value="root" /> 账号
               <property name="password" value="root" /> 密码
           </dataSource>
       </environment>
   </environments>
   <mappers>
       <mapper resource="model/UserMapper.xml" /> 映射文件
   </mappers>
</configuration>

4.映射文件 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">
<mapper namespace="dao.IUserIn">
<resultMap type="model.User" id="uMap">
<id column="id" property="id"/> 主键写法  column表列   property类属性
<result column="userName" property="useraName"/> 其他写法
<result column="userAge" property="userAge"/>
<result column="userAddress" property="userAddress"/>
</resultMap>
   
   <select id="selectUserByID" parameterType="int" resultMap="uMap">
   select * from user_m where id=#{id}
   </select>
   <select id="insert" parameterType="model.User">
   insert into user_m values(#{id},#{userName},#{userAge},#{userAddress})
   </select>
   <select id="delete" parameterType="model.User">
   delete from user_m where id=#{id}
   </select>
   <select id="update" parameterType="model.User">
   update user_m set userAge=#{userAge} where id=#{id}
   </select>
</mapper>

5.代理接口

public interface IUserIn {

   public User selectUserByID(int id);

   public void insert(User user);

   public void delete(int i);

   public void update(User user);

}
6.测试类

public class UserTest {
   SqlSessionFactory factory=null;

   @Before
   public void Init() throws IOException{
       //1.指定配置文件路径
       String resource = "mybatis-config.xml";
       //2.加载配置文件
       InputStream inputStream = Resources.getResourceAsStream(resource);
       //3.获取一个session工厂
       SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
       factory = builder.build(inputStream);
   }

@Test
public void que(){
   SqlSession session=factory.openSession();
   IUserIn iUserIn=session.getMapper(IUserIn.class);
   User user=iUserIn.selectUserByID(1);
   System.out.println(user.getId()+" "+user.getUseraName());
   session.close();
}
@Test
public void insert(){
   SqlSession session=factory.openSession();
   IUserIn iUserIn=session.getMapper(IUserIn.class);
   User user=new User(7,"66","88","45");
   iUserIn.insert(user);
   session.commit();
   session.close();
}

}

MyBatis使用Mapper动态代理

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