MyBatis源码- SqlSession门面模式 & selectList 源码解析

阳光穿透心脏的1/2处 2023-02-17 12:24 5阅读 0赞

### 文章目录 ###

*  Pre
 *  工程概览
 *  pom.xml
 *  mybatis-config.xml
 *  UserMapper
 *  测试类
 *  selectList 源码解析
 *  附
 *   *  SQL
     *  log4j.properties
     *  app.properties
     *  User

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70]

# Pre #

如果MyBatis的基础用法还不熟悉，31篇入门博客拿走不谢

[戳戳戳 —> https://blog.csdn.net/yangshangwei/category\_7205317.html][_ https_blog.csdn.net_yangshangwei_category_7205317.html]

![在这里插入图片描述][20200604233018261.png]

--------------------

# 工程概览 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 1]

--------------------

# pom.xml #

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.artisan</groupId>
        <artifactId>mybatisSource</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <dependencies>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.17</version>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.1</version>
            </dependency>
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>1.2.17</version>
            </dependency>
        </dependencies>
    
        <build>
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.xml</include> </includes> <filtering>true</filtering> </resource> <resource> <directory>src/test/java</directory> <includes> <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
            </resources>
        </build>
    
    </project>

--------------------

# 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>
    
         <properties resource="app.properties">
        </properties>
        <settings>
            <setting name="mapUnderscoreToCamelCase" value="true"/>
    
        </settings>
        <typeAliases>
        </typeAliases>
    
        <environments default="dev">
            <environment id="dev">
                <transactionManager type="JDBC"/>
                <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>
    
        <mappers>
            <package name="com.artisan"/>
        </mappers>
    </configuration>

--------------------

# UserMapper #

package com.artisan;
    
    import com.artisan.bean.User;
    import org.apache.ibatis.annotations.Select;
    
    
    public interface UserMapper { 
        @Select({ "select * from users where id = #{id}"})
        User selectByid(Integer id);
    }

--------------------

# 测试类 #

基类

import org.apache.ibatis.session.Configuration;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.junit.Before;
    
    
    /** * 基类 */
    public class BaseTest { 
    
        public SqlSessionFactory factory;
        public Configuration configuration; 
    
        @Before
        public void inin(){ 
            // 获取构建器
            SqlSessionFactoryBuilder factoryBuilder = new SqlSessionFactoryBuilder();
            // 解析xml ,构建会话工厂
            factory = factoryBuilder.build(SqlSessionTest.class.getResourceAsStream("/mybatis-config.xml"));
            // 获取 configuration 这个大管家
            configuration = factory.getConfiguration();
        }
    }

SqlSessionTest 测试类

package com.artisan;
    
    import com.artisan.bean.User;
    import org.apache.ibatis.mapping.MappedStatement;
    import org.apache.ibatis.session.ExecutorType;
    import org.apache.ibatis.session.SqlSession;
    import org.junit.Test;
    
    import java.util.List;
    
     
    public class SqlSessionTest  extends  BaseTest{ 
    
        private MappedStatement ms;
    
        @Test
        public void sqlSessionTest(){ 
    
            // 获取statement SQL映射
            ms = configuration.getMappedStatement("com.artisan.UserMapper.selectByid");
    
            // 开启会话 第一个参数 执行器类型 第二个参数 是否自动提交
            SqlSession sqlSession = factory.openSession(ExecutorType.SIMPLE, true);
            // 门面模式 屏蔽了底层调用的复杂用 统一对接sqlSession
            List<User> users = sqlSession.selectList(ms.getId(), 1);
            System.out.println(users.get(0));
    
        }
    }

测试结果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 2]

--------------------

# selectList 源码解析 #

--------------------

# 附 #

## SQL ##

/* Navicat MySQL Data Transfer Source Server : localhost_root Source Server Version : 80011 Source Host : 127.0.0.1:3306 Source Database : artisan Target Server Type : MYSQL Target Server Version : 80011 File Encoding : 65001 Date: 2020-06-14 00:46:05 */
    
    SET FOREIGN_KEY_CHECKS=0;
    
    -- ----------------------------
    -- Table structure for `users`
    -- ----------------------------
    DROP TABLE IF EXISTS `users`;
    CREATE TABLE `users` (
      `id` int(11) NOT NULL,
      `name` varchar(255) DEFAULT NULL,
      `age` varchar(255) DEFAULT NULL,
      `sex` varchar(255) DEFAULT NULL,
      `email` varchar(255) DEFAULT NULL,
      `phoneNumber` varchar(255) DEFAULT NULL,
      `createTime` date DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    
    -- ----------------------------
    -- Records of users
    -- ----------------------------
    INSERT INTO `users` VALUES ('1', 'artisan', '11', 'male', '123@qq.com', '12345', '2020-06-04');

## log4j.properties ##

### set log levels ###
    log4j.rootLogger = DEBUG ,stdout
    
    ### 
    log4j.appender.stdout = org.apache.log4j.ConsoleAppender
    log4j.appender.stdout.Target = System.out
    log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
    log4j.appender.stdout.layout.ConversionPattern =  %d{ ABSOLUTE} %5p %c:%L - %m%n

--------------------

## app.properties ##

jdbc.driver=com.mysql.cj.jdbc.Driver
    jdbc.url=jdbc:mysql://127.0.0.1:3306/artisan?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT
    jdbc.username=root
    jdbc.password=root
    default.environment=dev

--------------------

## User ##

package com.artisan.bean;
    
    
    import java.util.Date;
    
    public class User implements java.io.Serializable { 
        private Integer id;
        private String name;
        private String age;
        private String sex;
        private String email;
        private String phoneNumber;
        private Date createTime;
    
        public User() { 
        }
    
        public User(Integer id, String name) { 
            this.id = id;
            this.name = name;
        }
        ....省略 set/get 
        ....
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200604232843431.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ==,size_16,color_FFFFFF,t_70
[_ https_blog.csdn.net_yangshangwei_category_7205317.html]: https://blog.csdn.net/yangshangwei/category_7205317.html
[20200604233018261.png]: https://img-blog.csdnimg.cn/20200604233018261.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200614163433554.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200614115254286.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ==,size_16,color_FFFFFF,t_70