MyBatis学习（一）一个简单的例子

 求职中，加紧学习。

我对MyBatis的理解仅仅是：它以前叫IBtais，现在投到谷歌帐下，改名MyBatis，这个框架把JDBC中的重复代码封装起来，减少代码量。仅仅知道这些而已，慢慢学习吧，从网上找了一个最简单的例子。

MyBatis+MySQL的，记录如下：

①数据库

在MySQL中，test数据库下，简历user表，一共两个字段id和name，建表语句略。

②需导入的包

只有两个：

mybatis-3.0.3.jar

mysql-connector-java-5.1.9-bin.jar（JDBC包）

③目录结构

采用最简单的结构，domain包下有且仅有四个文件

configuration.xml

User.xml

User.java

Test.java

④实体类javabean，总共两个变量

package domain;

public class User {
private int id;
private String name = null;
public User() {
}
public User(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + "]";
}
}

 

⑤MyBatis总配置文件configuration.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>
<typeAliases>
<typeAlias alias="User" type="domain.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?useUnicode=true&characterEncoding=UTF-8" />
<property name="username" value="root" />
<property name="password" value="" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="domain/User.xml" />
</mappers>
</configuration>

⑥User类的配置文件User.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="User">
<select id="selectUser" parameterType="int" resultType="User"><!--[CDATA[
select * from user where id = #{id}
]]--></select>
</mapper>

⑦测试用例

package domain;

import java.io.IOException;
import java.io.Reader;
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 domain.User;

public class Test {
public static void main(String[] args) throws IOException {
String resource = "domain/configuration.xml";
Reader reader = Resources.getResourceAsReader(resource);
SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(reader);
SqlSession session = ssf.openSession();
try {
User user = (User) session.selectOne("selectUser", "1");
System.out.println(user);
} catch (Exception e) {
e.printStackTrace();
} finally {
session.close();
}
}
}

 

以上，MyEclipse 8.5下编译通过