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;}@Overridepublic 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