mybatis源码环境搭建

偏执的太偏执、 2022-12-24 15:47 177阅读 0赞

## 前言 ##

mybatis在众多的数据持久化框架中应该说是目前使用最多的，其优秀的设计和底层封装，值得很多开发人员进行学习，下面让我们先来构建一下mybatis的源码阅读环境吧

## 准备 ##

**1、github下载mybatis源码**

https://github.com/mybatis/parent/tree/mybatis-parent-30

**2、导入idea**

将下载好的源码，通过idea导入，在开始编译之前，需要修改pom文件中的几处配置，避免构建过程中报错

**找到ognl坐标依赖**

将true标签的true修改为false或者直接注释调

<dependency>
    			<groupId>ognl</groupId>
    			<artifactId>ognl</artifactId>
    			<version>3.2.10</version>
    			
    			
    		</dependency>

**找到pdf坐标依赖**

直接注释调即可

<plugin>
    	<groupId>org.apache.maven.plugins</groupId>
    	<artifactId>maven-pdf-plugin</artifactId>
    </plugin>

**执行打包命令**

mvn clean install -Dmaven.test.skip=true

首次编译安装，需要下载大量的依赖，比较花费时间，经过漫长的等待，看到如下的build success之后，就可以开始编写代码了

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw_size_16_color_FFFFFF_t_70]

**demo导入本地mybatis**

下面我们来快速搭建一个mybatis的工程，并引用上面使用源码构建好的mybatis依赖包

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw_size_16_color_FFFFFF_t_70 1]

项目结构非常简单，如图中所示

**pom依赖**

<dependencies>
    
            
            
    
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.0-SNAPSHOT</version>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.35</version>
            </dependency>
    
            
            <dependency>
                <groupId>com.github.pagehelper</groupId>
                <artifactId>pagehelper</artifactId>
                <version>5.1.6</version>
            </dependency>
    
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>1.2.17</version>
            </dependency>
    
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
            
        </dependencies>

**db.properties**

db.driver=com.mysql.jdbc.Driver
    db.url=jdbc:mysql://IP:3306/test?characterEncoding=utf-8
    db.username=root
    db.password=123456

**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>
    	<properties resource="demo1/db.properties"></properties>
    	<environments default="development">
    		<environment id="development">
    			<transactionManager type="JDBC" />
    			<dataSource type="POOLED">
    				<property name="driver" value="${db.driver}" />
    				<property name="url" value="${db.url}" />
    				<property name="username" value="${db.username}" />
    				<property name="password" value="${db.password}" />
    			</dataSource>
    		</environment>
    	</environments>
    	<mappers>
    		<mapper resource="demo1/UserMapper.xml" />
    	</mappers>
    
    </configuration>

**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="test">
    
        <select id="findUserById" parameterType="int" resultType="com.congge.demo1.entity.User">
    		SELECT * FROM user WHERE id = #{id}
    	</select>
        
    </mapper>

关于上面这几个配置文件的作用，想必使用过ssm框架或对mybatis框架了解的都知道了，然后再编写一个简单的接口和实现类

**UserDao**

User findUserById(int id);

**UserDaoImpl**

public class UserDaoImpl implements UserDao {
    
    	private SqlSessionFactory sqlSessionFactory;
    
    	// 注入sqlSessionFactory
    	public UserDaoImpl(SqlSessionFactory sqlSessionFactory) {
    		this.sqlSessionFactory = sqlSessionFactory;
    	}
    
    	@Override
    	public User findUserById(int id) {
    		// sqlsessionFactory工厂类去创建sqlsession会话
    		SqlSession sqlSession = sqlSessionFactory.openSession();
    		// sqlsession接口，开发人员使用它对数据库进行增删改查操作
    		User user = sqlSession.selectOne("test.findUserById", id);
    		return user;
    	}
    
    }

**测试类**

public class DemoTest1 {
    
        private SqlSessionFactory sqlSessionFactory;
    
        @Before
        public void init() throws Exception{
            // 加载全局配置文件（同时把映射文件也加载了）
            String resource = "demo1/SqlMapConfig.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            // sqlsessionFactory需要通过sqlsessionFactoryBuilder读取全局配置文件信息之后
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        }
    
        @Test
        public void testFindUserById() {
            UserDao dao = new UserDaoImpl(sqlSessionFactory);
            User user = dao.findUserById(1);
            System.out.println(user);
        }
    }

运行testFindUserById这个单元测试方法，可看到，从数据库查询到一条结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw_size_16_color_FFFFFF_t_70 2]

到这里，我们完成了mybatis的源码安装与构建，并通过工程的形式导入源码包并完成了测试，下一步让我们通过源码的方式来逐步深入学习mybatis的底层架构吧

**本篇到此结束，最后感谢观看！**

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw_size_16_color_FFFFFF_t_70]: /images/20221120/bf1dd64094fb430f92aafc7ea96cb794.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20201129101709185.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/2020112910221653.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nY29uZ3lpNDIw,size_16,color_FFFFFF,t_70