『MyBatis技术内幕』源码调试前提

准备源代码包

1. 下载源代码 3.4.6 版本
   https://github.com/mybatis/mybatis-3/releases?page=2
   
2. 通过 idea 导入然后回自动下载所有依赖，根据 3.4.6 版本的 pom.xml 找到依赖的 mybatis-parent 版本

  <parent><groupId>org.mybatis</groupId><artifactId>mybatis-parent</artifactId><version>29</version><relativePath /></parent>

3. 同样需要从 github 下载
   https://github.com/mybatis/parent/releases/tag/mybatis-parent-29

准备测试环境

1. 代码结构
   
2. 创建 Maven 项目，并添加依赖 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>org.example</groupId><artifactId>mybatisjsnm</artifactId><version>1.0-SNAPSHOT</version><properties><junit.version>4.12</junit.version><mybatis.version>3.4.6</mybatis.version><mysql.version>8.0.16</mysql.version><druid.version>1.0.9</druid.version></properties><dependencies><!-- log4j --><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version></dependency><!-- Mybatis --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>${mybatis.version}</version></dependency><!-- MySql --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>${mysql.version}</version></dependency><!-- 连接池 --><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>${druid.version}</version></dependency><!-- Junit --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>${junit.version}</version><scope>test</scope></dependency><!-- install 后源码缺包--><dependency><groupId>org.javassist</groupId><artifactId>javassist</artifactId><version>3.26.0-GA</version></dependency><!-- install 后源码缺包--><dependency><groupId>ognl</groupId><artifactId>ognl</artifactId><version>3.0.6</version></dependency></dependencies><build><finalName>mybatis</finalName><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><configuration><source>1.8</source><target>1.8</target><encoding>UTF-8</encoding></configuration></plugin></plugins></build>
</project>

3. 创建 mapper 接口 CountryMapper

public interface CountryMapper {public List<Country> selectAll();
}

4. 创建实体类 Country

public class Country {private Long id;private String countryname;private String countrycode;... // get/set 方法
}

• 相应字段自行在数据库里面创建

create table `country` (`id` int (11),`countryname` varchar (765),`countrycode` varchar (765)
); 

5. 创建 CountryMapper.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="org.example.mybatisjsnm.mapper.CountryMapper"><select id="selectAll" resultType="Country">select id,countryname,countrycode from country</select>
</mapper>

6. 配置 log4j.properties

# Global logging configuration
log4j.rootLogger=ERROR,stdout
# Mybatis logging configuration...
log4j.logger.com.simple.mapper=TRACE
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.layout.ConversionPattern=%5p [%t] - %m%n

7. 配置 mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--开启日志输出--><settings><setting name="logImpl" value="STDOUT_LOGGING" /></settings><!--配置类别名，配置后在Mapper配置文件（通常我们将编写SQL语句的配置文件成为Mapper配置文件）中需要使用pojo包中的类时，使用简单类名即可--><typeAliases><package name="org.example.mybatisjsnm.pojo"/></typeAliases><environments default="development"><environment id="development"><transactionManager type="JDBC"><property name="" value=""/></transactionManager><dataSource type="POOLED"><property name="driver" value="com.mysql.cj.jdbc.Driver"/><property name="username" value="root"/><property name="password" value="root"/><property name="url" value="jdbc:mysql://localhost:3306/mybatis"/></dataSource></environment></environments><mappers><package name="org.example.mybatisjsnm.mapper"/></mappers></configuration>

8. 创建运行主类 MyBatisTest

public class MyBatisTest {@Testpublic void testMyBatisBuild() throws IOException {InputStream input = Resources.getResourceAsStream("mybatis-config.xml");SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(input);SqlSession sqlSession = sessionFactory.openSession();CountryMapper mapper = sqlSession.getMapper(CountryMapper.class);List<Country> countries = mapper.selectAll();}
}

9. 运行程序
   

集合成源代码

1. 代码结构
   
2. 首先将 mybatis-3-mybatis-3.4.6、parent-mybatis-parent-29 导入到刚刚测试的相同 project 中，导入方式 File -> Project Structure -> Modules -> +号
3. 然后分别在 mybatis-3-mybatis-3.4.6、parent-mybatis-parent-29 执行下面命令

mvn clean install -Dmaven.test.skip=true

4. 如果 mybatis-3-mybatis-3.4.6 显示 maven-pdf-plugin 相关的失败的话，把这个插件注释掉

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

5. 然后再尝试 debug、运行代码，看看是否能跳转到你相应代码上