MyBatis入門學習（一）

weixin_34391854發表於2015-03-13
MyBatis

所須要jar包：mybatis-3.x.x.jar 、假設須要和spring整合，還須要增加相關的包

1：看專案資料夾 紅顏色不要關心

2：依照步驟：

1：增加jar包

2：建立資料來源（configuration.xml）建立資料庫（此處省略）

<?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>
		<!--給實體類起一個別名 user -->
		<typeAlias type="com.forum.po.User" alias="User" />
	</typeAliases>
	<!--資料來源配置  這塊用 BD2資料庫 -->
	<environments default="development">
		<environment id="development">
			<transactionManager type="jdbc" />
			<dataSource type="POOLED">
				<property name="driver" value="com.ibm.db2.jcc.DB2Driver" />
				<property name="url" value="jdbc:db2://localhost:50000/forum" />
				<property name="username" value="DB2ADMIN" />
				<property name="password" value="admin" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<!--userMapper.xml裝載進來  同等於把“dao”的實現裝載進來 -->
		<mapper resource="myBatis/userMapper.xml" />
	</mappers>
</configuration>
3：建立實體類USER 

package com.forum.po;

/**
 * 使用者類
 * 
 * @author db2admin
 * 
 */
public class User extends Entity {
	private String name;
	private Integer age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public User() {
	}

}

4：建立dao介面、能夠說是Mapper介面：UserMapper 

package com.forum.dao;

import com.forum.po.User;

public interface UserMapper {
	public User findById(String Id);
}

5:建立dao的實現，不同於hibernarte的此處的實現為一個xml檔案，也就是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">
	<!--這塊等於dao介面的實現  namespace必須和介面的類路徑一樣-->
<mapper namespace="com.forum.dao.UserMapper">
	<!-- findById必須和介面中的方法名一樣  返回一個User  就是剛才的別名  假設不弄別名要連類路徑一起寫 麻煩-->
	<select id="findById" parameterType="HashMap" resultType="User">
		select
		* from butone.student where id=#{id}
    </select>
</mapper>

6:測試類，MyBatisTest 

package com.forum.test;

import java.io.IOException;

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 com.forum.dao.UserMapper;
import com.forum.po.User;

/**
 * myBatis資料庫連線測試
 * 
 * @author db2admin
 * 
 */
public class MyBatisTest {
	/**
	 * 獲得MyBatis SqlSessionFactory  
	 * SqlSessionFactory負責建立SqlSession，一旦建立成功，就能夠用SqlSession例項來執行對映語句，commit，rollback，close等方法。
	 * @return
	 */
	private static SqlSessionFactory getSessionFactory() {
		SqlSessionFactory sessionFactory = null;
		String resource = "configuration.xml";
		try {
			sessionFactory = new SqlSessionFactoryBuilder().build(Resources
					.getResourceAsReader(resource));
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return sessionFactory;
	}

	public static void main(String[] args) {
		SqlSession sqlSession = getSessionFactory().openSession();
		UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
		User user = userMapper.findById("1");
		System.out.println(user.getName());

	}

}

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