Mybatis框架-----Mapper动态代理的使用

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🍎合抱之木,生于毫末;百丈之台,起于垒土;千里之行,始于足下。------《老子》
🍊今日学习任务！！！！！
🍊1、Mapper动态代理的使用

🔥一、Mapper动态代理的使用

🍎项目结构

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🍎mybatis配置文件

<?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>
    <!--引入db.properties属性文件-->
    <properties resource="db.properties"/>

    <settings>
        <setting name="useGeneratedKeys" value="true"/>
    </settings>

    <!--配置别名-->
    <typeAliases>
        <package name="com.bjsxt.pojo"/>
    </typeAliases>

    <!--配置环境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <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>

    <!--引入Mapper映射配置文件-->
    <mappers>
        <package name="wr.oyc.mapper"/>
    </mappers>
</configuration>

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🍎MybatisUtils工具类

package wr.oyc.utils;

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;
import java.io.InputStream;

public class MybatisUtils {
    private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<>();
    private static SqlSessionFactory sqlSessionFactory = null;
    static{
        //创建SqlSessionFactory
        InputStream is = null;
        try{
            is = Resources.getResourceAsStream("mybatis-cfg.xml");
        }catch (IOException e){
            e.printStackTrace();
        }
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
    }

    //获取SqlSession
    public static SqlSession getSqlSession(){
        SqlSession sqlSession = threadLocal.get();
        if(sqlSession == null){
            sqlSession = sqlSessionFactory.openSession();
            threadLocal.set(sqlSession);
        }
        return sqlSession;
    }

    //关闭SqlSession
    public static void closeSqlSession(){
        SqlSession sqlSession = threadLocal.get();
        if(sqlSession != null){
            sqlSession.close();
            threadLocal.set(null);
        }
    }
}

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🍎绑定 (接口类中方法名与id值相同 , xml文件中namespace是接口类的全称)

<?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="wr.oyc.mapper.UsersMapper">
    <cache/>
    <!--查询所有用户-->
    <select id="selectUsersAll" resultType="users">
         select * from users
    </select>


</mapper>

接口类

package wr.oyc.mapper;

import wr.oyc.pojo.Users;

import java.util.List;

public interface UsersMapper {
//查詢用戶
    List<Users> selectUsersAll();
}

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🍑每日一夸！！！
🍑就如同薛之謙对毛不易夸奖的
🍑"你现在就是流星" , 但是我相信你 ,你坚持下去你就是巨星"