MyBatis 增、删、改、查操作

柔情只为你懂 2022-05-15 00:08 183阅读 0赞

**示例：【MyBatis  增、删、改、查操作】**

**项目结构如下：**

![70][]

**创建mybatis-config.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>
    	
    	<environments default="mysql">
    		<environment id="mysql">
    			
    			<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/mapper/UserMapper.xml"/>
    	</mappers>
    </configuration>

**创建SessionFactory**

package com.factory;
    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 SessionFactory {
    	private static SqlSessionFactory sessionFactory=null;
    	//初始化创建SqlSessionFactory对象
    	static {		
    				try {
    					//读取配置文件
    					InputStream	is = Resources.getResourceAsStream("mybatis-config.xml");
    					//根据配置文件构建SqlSessionFactory
    					sessionFactory=new SqlSessionFactoryBuilder().build(is);
    				} catch (IOException e) {
    					e.printStackTrace();
    				}				
    	}
    	//获取SqlSession对象
    	public static SqlSession getSqlSession() {
    		return sessionFactory.openSession();
    	}
    	// 获取SqlSessionFactory
    	public static SqlSessionFactory getSqlSessionFactory() {
    		return sessionFactory;
    	}
    }

**创建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">
    
    <mapper namespace="com.mapper.UserMapper">	
    	
    	<insert id="addUser" parameterType="com.po.User">
    		insert into t_user(username,password) values(#{username},#{password})
    	</insert>
    	
    	<delete id="deleteUser" parameterType="int">
    		delete from t_user where uid=#{uid}
    	</delete>
    	
    	<update id="updateUser" parameterType="com.po.User">
    		update t_user set username=#{username},password=#{password} where uid=#{uid}
    	</update>
    	
    	<select id="getUserById" parameterType="Integer" resultType="com.po.User">
    		select * from t_user where uid=#{uid}
    	</select>
    	
    	<select id="getUsers" resultType="com.po.User">
    		select * from t_user
    	</select>
    	
    	<select id="findUser" resultType="com.po.User" parameterType="String">
    		select * from t_user where username like CONCAT('%',#{username},'%')
    	</select>
    </mapper>

**创建UserDao**

package com.dao;
    import java.util.List;
    import org.apache.ibatis.session.SqlSession;
    import com.factory.SessionFactory;
    import com.po.User;
    public class UserDao {
    	private SqlSession session=SessionFactory.getSqlSession();
    	private User user;
    	private List<User> users;	
    	public SqlSession getSession() {
    		return session;
    	}
    	//增加用户
    	public void addUser(User user) {
    		session.insert("com.mapper.UserMapper.addUser",user);
    		session.commit();
    		session.close();
    	}
    	//删除用户
    	public void deleteUser(int id) {
    		session.delete("com.mapper.UserMapper.deleteUser", id);
    		session.commit();
    		session.close();
    	}
    	//根据 id查询用户
    	public User getUserById(Integer id) {
    		user=session.selectOne("com.mapper.UserMapper.getUserById", id);
    		session.commit();
    		session.close();
    		return user;
    	}
    	//查询所有用户
    	public List<User> getUsers(){
    		users=session.selectList("com.mapper.UserMapper.getUsers");
    		session.commit();
    		session.close();
    		return users;
    	}
    	//模糊查询
    	public List<User> findUser(String username){
    		users=session.selectList("com.mapper.UserMapper.findUser",username);
    		session.commit();
    		session.close();
    		return users;
    	}
    	//更新用户
    	public void updateUser(User user,int id) {
    		User u=new User();
    		u=session.selectOne("com.mapper.UserMapper.getUserById", id);
    		u.setUsername(user.getUsername());
    		u.setPassword(user.getPassword());
    		session.update("com.mapper.UserMapper.updateUser", u);
    		session.commit();
    		session.close();
    	}
    }

**创建Test**

package com.test;
    import java.util.List;
    import com.dao.UserDao;
    import com.po.User;
    public class Test {
    	public static void main(String[] args) {
        
    	}
    }

**增加用户**

public static void main(String[] args) {
    		UserDao userDao=new UserDao();
    		User user=new User();
    		user.setUsername("user");
    		user.setPassword("user123");
    		userDao.addUser(user);
    	}

![70 1][]

**删除用户**

public static void main(String[] args) {
    		UserDao userDao=new UserDao();
    		userDao.deleteUser(12);
    
    	}

![70 2][]

**修改用户**

public static void main(String[] args) {
    		UserDao userDao=new UserDao();
    		User user=new User();
    		user.setUsername("李四");
    		user.setPassword("5622");
    		userDao.updateUser(user, 3);
    
    	}

![70 3][]

**根据id查询用户**

public static void main(String[] args) {
    		UserDao userDao=new UserDao();
    		User user=userDao.getUserById(1);
    		System.out.println(user);
    
    	}

![70 4][]

**模糊查询用户**

public static void main(String[] args) {
    		UserDao userDao=new UserDao();
    		List<User> users=userDao.findUser("an");
    		for (User u : users) {
    			System.out.println(u);
    		}
    	}

![70 5][]

[70]: /images/20220515/c5dbe8e724bd442a855a72199009cde4.png
[70 1]: /images/20220515/069c42279aba48c7bedad4100846c6f8.png
[70 2]: /images/20220515/b03de84705de4072aced41304d9dcec2.png
[70 3]: /images/20220515/412cc97c4738412d98e2ee9bd85a8a33.png
[70 4]: /images/20220515/f37f52978cb343ec933f247f662bd44f.png
[70 5]: /images/20220515/7fa01e8179d54ca7b4fc8f5fde7d0e6e.png