使用mybatis实现CRUD

本文介绍的是mybatis3的使用，针对使用mybatis3作为持久层框架的入门学习。下面具体讲解：

1. mybatis需要程序员手动建表，用于测试的建表语句如下：

   --oracle10g
   CREATE TABLE user_tbl (
     id int PRIMARY KEY ,
     name varchar2(20),
     age int,
     sex varchar2(5),
     password varchar2(20)
   )
   
   create sequence user_seq;
   INSERT INTO user_tbl VALUES (1, 'zs',18, '张三', 'zs');
   

    
2. 连接数据库的工具类：
   

   package 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;
   
   /**
    * 连接数据库的工具类
    * @author Jzl
    *
    */
   public class MybatisUtil {
   	private static SqlSessionFactory sessionFactory;
   	private SqlSession session;
   
   	static {
   		String resource = "mybatis3-config.xml";
   		InputStream inputStream = null;
   		try {
   			inputStream = Resources.getResourceAsStream(resource);
   		} catch (IOException e) {
   			e.printStackTrace();
   		}
   		sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
   	}
   
   	public static SqlSessionFactory getSqlsessionfactory() {
   		return sessionFactory;
   	}
   
   	public static SqlSession getSession() {
   		return sessionFactory.openSession(false);
   	}
   
   	public void closeSession(SqlSession session) {
   		if (session != null) {
   			session.close();
   			session = null;
   		}
   	}
   }
   
   

    
3. UserDao，用于实现对User表的CRUD操作：
   

   package dao;
   
   import java.util.List;
   
   import entity.User;
   
   public interface UserDao {
   	public List<User> getUserByName(String name);
   	
   	public List<User> getAllUser();
   
   	public User getUser(String name);
   	
   	public void insertUser(User user);
   	
   	public void updateUser(User user);
   	
   	public void deleteUser(int id);
   }
   
   

    
4. 不同于hibernate，mybatis映射文件（这里是UserDao.xml）映射的是Dao层的方法，用于将Dao层的方法与具体的sql语句绑定。
   

   <?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="dao.UserDao">
   	<select id="getAllUser" resultType="entity.User">
   		select * from user_tbl
   	</select>
   
   	<select id="getUserByName" parameterType="String" resultType="entity.User">
   		select * from user_tbl
   		where name like #{name}
   	</select>
   
   	<select id="getUser" parameterType="String" resultType="entity.User">
   		select * from user_tbl where
   		name=#{name}
   	</select>
   
   	<insert id="insertUser" parameterType="entity.User">
   		<selectKey resultType="int" order="BEFORE" keyProperty="id">
   			select user_seq.nextval from dual
   		</selectKey>
   		insert into user_tbl (id,name,age,sex,password)
   		values
   		(#{id},#{name},#{age},#{sex},#{password})
   	</insert>
   
   	<update id="updateUser" parameterType="entity.User">
   		update user_tbl set name = #{name},age =
   		#{age},
   		sex = #{sex},password = #{password} where id = #{id}
   	</update>
   
   	<delete id="deleteUser" parameterType="int">
   		delete from user_tbl where id = #{id}
   	</delete>
   </mapper>
   

    
5. 实体类User如下：
   

   package entity;
   
   public class User {
   	private int id;
   	private String name;
   	private int age;
   	private String sex;
   	private String password;
   
   	public User() {
   		System.out.println("--调用无参数构造方法--");
   	}
   	
   	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;
   	}
   
   	public String getSex() {
   		return sex;
   	}
   
   	public void setSex(String sex) {
   		this.sex = sex;
   	}
   
   	public String getPassword() {
   		return password;
   	}
   
   	public void setPassword(String password) {
   		this.password = password;
   	}
   }
   
   

    
6. 最后就可以测试了，测试类TestUser如下：
   

   package test;
   
   import java.util.List;
   
   import org.apache.ibatis.session.SqlSession;
   import org.junit.Test;
   
   import util.MybatisUtil;
   import dao.UserDao;
   import entity.User;
   
   public class TestUser {
   
   	public void testGetByName() {
   		SqlSession session = MybatisUtil.getSession();
   		List<User> users = session.selectList("getUserByName", "%s%");
   		for (User user : users) {
   			System.out.println(user.getId() + "==" + user.getName());
   		}
   		session.commit();
   		session.close();
   	}
   
   	public void testGetAll() {
   		SqlSession session = MybatisUtil.getSession();
   		List<User> users = session.selectList("getAllUser");
   		for (User user : users) {
   			System.out.println(user.getId() + "==" + user.getName());
   		}
   		session.commit();
   		session.close();
   	}
   
   	public void testGet() {
   		SqlSession session = MybatisUtil.getSession();
   		UserDao userDao = session.getMapper(UserDao.class);
   		User user = userDao.getUser("zs");
   		System.out.println(user.getId() + "==" + user.getName());
   		session.commit();
   		session.close();
   	}
   
   	@Test
   	public void testAdd() {
   		SqlSession session = MybatisUtil.getSession();
   		UserDao userDao = session.getMapper(UserDao.class);
   		User user = new User();
   		// user.setId(10);
   		user.setName("zs");
   		user.setPassword("zs");
   		user.setAge(20);
   		user.setSex("女");
   		try {
   			userDao.insertUser(user);
   			System.out.println("id:" + user.getId());
   			// session.commit();
   		} catch (Exception e) {
   			e.printStackTrace();
   		}
   		// session.close();
   	}
   
   	public void testUpdate() {
   		SqlSession session = MybatisUtil.getSession();
   		UserDao userDao = session.getMapper(UserDao.class);
   		User user = userDao.getUser("sb");
   		user.setName("sa");
   		user.setAge(19);
   		userDao.updateUser(user);
   		session.commit();
   		session.close();
   	}
   
   	public void testDelete() {
   		SqlSession session = MybatisUtil.getSession();
   		UserDao userDao = session.getMapper(UserDao.class);
   		userDao.deleteUser(1001);
   		session.commit();
   		session.close();
   	}
   }
   
   

    
7. 附上测试项目的源代码。