Mybatis初探之环境的配置

很早之前就想学习mybatis,据说很多公司都使用这个框架。以前我都使用老掉牙的DBCP，Hibernate感觉太大，现

在来学学这个中性的框架。

首先是环境的配置，我使用maven创建项目，pom.xml文件如下

<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.bird</groupId>
	<artifactId>concursey</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>concursey</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>3.8.1</version>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.2.7</version>
		</dependency>
		
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.32</version>
		</dependency>
	</dependencies>
</project>

还得创建一个数据库和对应的一张表做示范，这里就不写了，直接上对应的JavaBean

package com.bird.mybatis.bean;

public class Users {

	private int id;
	private String name;
	private int age;

	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;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Users [id=" + id + ", name=" + name + ", age=" + age + "]";
	}

}

然后要给对应的JavaBean创建对应的mapper.xml文件，内容如下

<?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="com.bird.mybatis.bean.userMapper">
	<!--根据ID获取对应的值  -->
	<select id="getUser" parameterType="int" resultType="com.bird.mybatis.bean.Users">
		select * from users where id = #{id}
	</select>
</mapper>

当然还有mybatis的全局文件，conf.xml内容如下

<?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>
<!-- development:开发模式     work:工作模式 -->
	<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/mybatis" />
				<property name="username" value="root" />
				<property name="password" value="root" />
			</dataSource>
		</environment>
	</environments>
	 
	<mappers>
		<mapper resource="com/bird/mybatis/bean/userMapper.xml" />
	</mappers>

</configuration>

最后是测试代码

package com.bird.mybatis.bean;

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;

public class Test {
	
	public static void main(String[] args) throws Exception {
		String resource = "conf.xml";
		Reader reader = Resources.getResourceAsReader(resource);
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		SqlSession session = sessionFactory.openSession();
		String statement = "com.bird.mybatis.bean.userMapper.getUser";
		Users user = session.selectOne(statement, 1);
		System.out.println(user);
	}
}

总体来说还是非常简单的。