mybatis学习demo1简单的查询

因为项目中要用mybatis,今天自己也看了下mybatis的基本知识,写了一个小demo
直接上代码,至于mybatis的一些基本的概念,可以网上百度下,还是很多的

项目结构如下:





1.首先写一个简单的实体类

package test.batics.entity;

import org.apache.ibatis.type.Alias;

@Alias("User")
public class User {
	private String loginName;
	private String password;
	private String email;
	private String name;
	private Long id;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public String getLoginName() {
		return loginName;
	}

	public void setLoginName(String loginName) {
		this.loginName = loginName;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

}

2.写一个mybatis的config配置文件

<?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>
   <!-- 别名 -->
    <typeAliases>
        <typeAlias type="test.batics.entity.User" alias="User" />
    </typeAliases>
   <!-- 数据库相关-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
                <property name="url"
                    value="jdbc:oracle:thin:@172.16.3.101:1521:ticketdb" />
                <property name="username" value="uds" />
                <property name="password" value="tempus" />
            </dataSource>
        </environment>
    </environments>
  <!-- 映射的mapper-->
    <mappers>
        <mapper resource="mapper/UserMapper.xml" />
    </mappers>
</configuration>

3.写一个接口,用来对应实体类映射文件中的namespace

package test.batics.service;

import java.util.List;

import test.batics.entity.User;

public interface UserMapper {
	User findById(Long id);
	
	List<User> findAll();
	
	
}

4.写实体类的映射文件,注意namespace对应的是之前的接口,其中2个方法,一个通过id查询,一个查询全部

<?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="test.batics.service.UserMapper">
	<select id="findById" parameterType="java.lang.Long" resultType="User">
		select * from t_user where id = #{value} 
	</select>
	<select id="findAll" resultType="User">
		select * from t_user
	</select>
</mapper>

5.写 一个工具类来得到sqlSession,增删改操作通过session来进行

package test.batics.util;

import java.io.IOException;
import java.io.InputStream;

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 BatisUtil {
	final static String RESOURCE = "config/mybatis_demo_config.xml";
	
	public static SqlSession getSession(){
		SqlSession session = null;
		InputStream inputStream = null;
		try {
			inputStream = Resources.getResourceAsStream(RESOURCE);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
			session = sqlSessionFactory.openSession();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return session;
	}
	
	public static void closeSession(SqlSession session){
		session.close();
	}
}

6.最后写一个测试类,提供两种方式

package test.batics.demo;

import java.util.List;

import org.apache.ibatis.session.SqlSession;

import test.batics.entity.User;
import test.batics.util.BatisUtil;

public class RunDemo {
	static final String NAME_SPACE = "test.batics.service.UserMapper";

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		SqlSession session = BatisUtil.getSession();
		// 第一种解决方案
		/*
		 * UserMapper mapper = session.getMapper(UserMapper.class); Long id =
		 * 2061L; User user = mapper.findById(id);
		 * System.out.println(user.getName());
		 * System.out.println("id="+user.getId());
		 */
		// 第二种解决方案
		List<User> users = session.selectList(NAME_SPACE + ".findAll");
		for (User user : users) {
			System.out.println("email=" + user.getEmail() + "\t" + "loginName="
					+ user.getLoginName() + "\t" + "name=" + user.getName()
					+ "\t" + "password=" + user.getPassword() + "\t" + "id="
					+ user.getId());
		}
	}
}

最后运行结果:




源码已经上传了,因为公司网络大家共用,实在是慢,所以jar包没有上传,jar包的下载地址是
http://mybatis.github.io/