Mybatis 之动态代理

使用Mybatis 开发Web 工程时，通过Mapper 动态代理机制，可以只编写接口以及方法的定义。

如下：

定义db.properties

driver=oracle.jdbc.OracleDriver

url=jdbc:oracle:thin:@localhost:1521:orcl

username=scott

password=tiger

定义SqlMapConfig.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>

    <!--引入外部 db.properties-->

    <properties resource="db.properties"/>

    <!--配置Oracle 数据库信息-->

    <environments default="development">

        <environment id="development">

            <transactionManager type="JDBC"></transactionManager>

            <dataSource type="POOLED">

                <property name="driver" value="${driver}"/>

                <property name="url" value="${url}"/>

                <property name="username" value="${username}"/>

                <property name="password" value="${password}"/>

            </dataSource>

        </environment>

    </environments>

    <mappers>

        <mapper resource="com/mapper/UserInfo.xml"/>

        <mapper resource="com/mapper/BatchCustomerOneToOne.xml"/>

        <mapper resource="com/mapper/BatchCustomerOneToMany.xml"/>

        <mapper resource="com/mapper/BatchCustomerManyToMany.xml"/>

        <mapper resource="com/mapper/DelayedLoading.xml"/>

        <mapper resource="com/service/impl/BatchCustomerMapper.xml"/>

    </mappers>

</configuration>

定义一个Mapper 接口：

package com.service.impl;

import com.entity.onetoonebyresultMap.Customer;

/**

 * @author 王立朝

 * @version 1.0

 * @description Mapper 动态代理类

 * * @date 2019/1/24

 **/

public interface BatchCustomerMapper {

    Customer findOneCustomerById(Integer integer);

}

定义Customer 实体类

package com.entity.onetoonebyresultMap;

/**

 * @author 王立朝

 * @version 1.0

 * @description com.entity.onetoonebyresultMap

 * @date 2019/1/19

 **/

public class Customer {

    //用户id

    private Integer cusId;

    //用户名

    private String username ;

    //卡号

    private String acno ;

    //性别

    private String gender ;

    //联系方式

    private String phone ;

    @Override

    public String toString() {

        return "Customer{" +

                "cusId=" + cusId +

                ", username='" + username + '\'' +

                ", acno='" + acno + '\'' +

                ", gender='" + gender + '\'' +

                ", phone='" + phone + '\'' +

                '}';

    }

    public Customer() {

    }

    public Integer getCusId() {

        return cusId;

    }

    public void setCusId(Integer cusId) {

        this.cusId = cusId;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getAcno() {

        return acno;

    }

    public void setAcno(String acno) {

        this.acno = acno;

    }

    public String getGender() {

        return gender;

    }

    public void setGender(String gender) {

        this.gender = gender;

    }

    public String getPhone() {

        return phone;

    }

    public void setPhone(String phone) {

        this.phone = phone;

    }

    public Customer(Integer cusId, String username, String acno, String gender, String phone) {

        this.cusId = cusId;

        this.username = username;

        this.acno = acno;

        this.gender = gender;

        this.phone = phone;

    }

}

定义BatchCustomerMapper.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="com.service.impl.BatchCustomerMapper">

    <select id="findOneCustomerById" parameterType="java.lang.Integer"

            resultType="com.entity.onetoonebyresultMap.Customer">

       select * from customer where cus_id = 4

    </select>

</mapper>

编写获取SqlSession 会话的工具类 DataConnection.java

package com.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;

import java.io.InputStream;

/**

 * @author 王立朝

 * @version 1.0

 * @description 获取 SqlSession 会话对象

 * @date 2019/1/13

 **/

public class DataConnection {

    //mybatis 配置文件

    private String resources = "SqlMapConfig.xml";

    private SqlSessionFactory sqlSessionFactory;

    private SqlSession sqlSession;

    public SqlSession getSqlSession() {

        try {

            InputStream inputStream = Resources.getResourceAsStream(resources);

            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

            sqlSession = sqlSessionFactory.openSession();

            System.out.println("获得连接");

        } catch (IOException e) {

            e.printStackTrace();

        }

        return sqlSession;

    }

    public static void main(String[] args) {

        DataConnection dataConnection = new DataConnection();

        dataConnection.getSqlSession();

    }

}

编写单元测试 testBatchCustomerMapper.java

import com.entity.onetoonebyresultMap.Customer;

import com.service.impl.BatchCustomerMapper;

import com.util.DataConnection;

import org.apache.ibatis.session.SqlSession;

import org.junit.Test;

/**

 * @author 王立朝

 * @version 1.0

 * @description PACKAGE_NAME

 * @date 2019/1/24

 **/

public class testBatchCustomerMapper {

    private static DataConnection dataConnection = new DataConnection();

    //测试Mapper 动态代理

    @Test

    public void testMapper(){

        SqlSession sqlSession = dataConnection.getSqlSession();

        BatchCustomerMapper batchCustomerMapper = sqlSession.getMapper(BatchCustomerMapper.class);

        Customer customer = batchCustomerMapper.findOneCustomerById(4);

        System.out.println("用户信息为："+ customer.getUsername()

                +" 性别为："+ customer.getGender());

    }

}

测试结果为：

巴特西

Mybatis 之动态代理

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