MyBatis原始碼實現之環境準備
阿新 • • 發佈：2018-12-21
一、引言
- 作為一名Java高階開發人員，閱讀原始碼的功底是其重要的基礎技能。除了Spring系列的原始碼之外，就是MyBatis的原始碼閱讀，好了，廢話不多說直接開幹。
- 宣告：這裡我使用的3.4.6版本。不同版本之間程式碼略有差異。
二、搭建
1.建立原始碼閱讀專案（Maven方式）
1.1 以Maven方式建立專案
在這裡我使用的idea建立的（過程略）。效果如下：
2.匯入MyBatis相關原始碼
2.1 下載官方原始碼
2.2 將原始碼匯入專案中
- 將解壓後的src\main\java裡面的：從org開始，把原始檔拷貝到第一步中建立的專案中（以java為根檔案），拷貝完畢後如下：
- 將mybatis-3-mybatis-3.4.6原始碼包中pom.xml中的依賴拷貝到原始碼專案的pom.xml中去，並新增上MySql連線的相關依賴。拷貝後代碼如下：
<?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.gyoomi</groupId> <artifactId>Learning-MyBatis</artifactId> <version>1.0-SNAPSHOT</version> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>ognl</groupId> <artifactId>ognl</artifactId> <version>3.1.16</version> <scope>compile</scope> <optional>true</optional> </dependency> <dependency> <groupId>org.javassist</groupId> <artifactId>javassist</artifactId> <version>3.22.0-GA</version> <scope>compile</scope> <optional>true</optional> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.25</version> <optional>true</optional> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.7.25</version> <optional>true</optional> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> <optional>true</optional> </dependency> <!-- Don't upgrade to 2.4+ until mybatis switches to java 7 --> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-core</artifactId> <version>2.3</version> <optional>true</optional> </dependency> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.2</version> <optional>true</optional> </dependency> <dependency> <groupId>cglib</groupId> <artifactId>cglib</artifactId> <version>3.2.5</version> <optional>true</optional> </dependency> <!-- Test dependencies --> <dependency> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> <version>4.12.2</version> <scope>test</scope> </dependency> <dependency> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>2.3.5</version> <!-- Version 2.4.0 required jdk8 --> <scope>test</scope> </dependency> <dependency> <groupId>org.apache.derby</groupId> <artifactId>derby</artifactId> <version>10.12.1.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mockito</groupId> <artifactId>mockito-core</artifactId> <version>2.12.0</version> <scope>test</scope> </dependency> <!-- Do not go to 2.x until we are on jdk7 --> <dependency> <groupId>commons-dbcp</groupId> <artifactId>commons-dbcp</artifactId> <version>1.4</version> <scope>test</scope> </dependency> <dependency> <groupId>org.jboss.spec.javax.transaction</groupId> <artifactId>jboss-transaction-api_1.2_spec</artifactId> <version>1.0.1.Final</version> <scope>test</scope> </dependency> <dependency> <groupId>org.apache.velocity</groupId> <artifactId>velocity</artifactId> <version>1.7</version> <scope>test</scope> </dependency> <!-- postgresql driver is required to run the refcursor tests --> <dependency> <groupId>org.postgresql</groupId> <artifactId>postgresql</artifactId> <version>42.1.4.jre6</version> <scope>test</scope> </dependency> <dependency> <groupId>org.assertj</groupId> <artifactId>assertj-core</artifactId> <version>1.7.1</version> <!-- Stay on 1.7.1 to support Java 6 --> <scope>test</scope> </dependency> <dependency> <groupId>eu.codearte.catch-exception</groupId> <artifactId>catch-exception</artifactId> <version>1.4.4</version> <scope>test</scope> </dependency> <dependency> <groupId>ru.yandex.qatools.embed</groupId> <artifactId>postgresql-embedded</artifactId> <version>2.5</version> <scope>test</scope> </dependency> <!-- mysql connector jar--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.6</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> </dependencies> </project>
3.建立測試用例
3.1 建立User表
CREATE TABLE `t_user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_name` varchar(255) DEFAULT NULL, `password` varchar(255) DEFAULT NULL, `deptment` varchar(255) DEFAULT NULL, `phone` varchar(255) DEFAULT NULL, `email` varchar(255) DEFAULT NULL, `status` int(11) DEFAULT NULL, `create_date` datetime DEFAULT NULL, `remark` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8mb4;
3.2 建立UserMapper介面和實現類
- UserMapper介面
public interface UserMapper {
User save(User user);
}
- UserMapper介面實現類
public class UserMapperImpl implements UserMapper {
private static final String NAME_SPACE = "UserMapper.";
private static SqlSessionFactory ssf;
private static Reader reader;
static {
try {
reader = Resources.getResourceAsReader("mybatis-config.xml");
ssf = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public User save(User user) {
SqlSession sqlSession = ssf.openSession();
int rows = sqlSession.insert(NAME_SPACE + "save", user);
sqlSession.commit();
if (rows > 0) {
return user;
} else {
return null;
}
}
}
3.3 建立MyBatis-config.xml和UserMapper.xml檔案
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>
<settings>
<setting name="cacheEnabled" value="true" />
<setting name="lazyLoadingEnabled" value="true"/>
<setting name="useGeneratedKeys" value="true"/>
</settings>
<typeAliases>
<typeAlias type="com.gyoomi.entity.User" alias="User"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/test"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="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="UserMapper">
<insert id="save" parameterType="User">
<selectKey keyProperty="id" resultType="java.lang.Integer" order="AFTER">
SELECT LAST_INSERT_ID();
</selectKey>
INSERT INTO t_user
(id, user_name, password, deptment, phone, email, status, create_date, remark)
VALUES
(null, #{userName}, #{password}, #{deptment}, #{phone}, #{email}, #{status}, #{createDate}, #{remark})
</insert>
</mapper>
3.4 建立測試的Main方法
建立Main.java(其實這裡是不規範的，一般是要寫JUnit單元測試的。)
public class Main {
public static void main(String[] args) {
UserMapper userMapper = new UserMapperImpl();
User user = new User();
user.setPassword("123");
user.setCreateDate(new Date());
user.setDeptment("研發部門");
user.setEmail("[email protected]");
user.setStatus(1);
user.setUserName("張三");
user.setPhone("13888888888");
user.setRemark("系統預設使用者");
User userToReturn = userMapper.save(user);
System.out.println(userToReturn);
}
}
4.測試環境
執行完上述3步後，整體的程式碼結構如下：
執行Main方法後，開啟資料看到t_user表新增了一條記錄。
支援MyBatis的原始碼閱讀的環境搭建並測試完畢。下面就讓我們開始暢快地閱讀原始碼吧！