14.MyBatis实现CURD操作

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1.新建一个java Dynamic Web Project

2.引入相关依赖包

3.新建mybatis.cfg.xml

新建一个source folder: config

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<?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">
  
<!-- MyBatis的整体配置 -->
<configuration>

	<!-- 数据源环境配置，default默认数据源的id -->
	<environments default="mysql_test">
		
		<!-- mysql 测试数据库 -->
		<environment id="mysql_test">
			
			<!-- mybatis的事务管理器 -->
			<transactionManager type="JDBC"></transactionManager>
			
			<!-- 配置数据库连接池 -->
			<dataSource type="POOLED">
				<property name="driver" value="com.mysql.jdbc.Driver"/>
				<property name="url" value="jdbc:mysql://localhost:3306/mybatis_test"/>
				<property name="username" value="root"/>
				<property name="password" value="123456"/>
			</dataSource>
		</environment>
		
		<!-- mysql 生产数据库 -->
		<!-- <environment id="mysql_prod"></environment> -->
		
		<!-- oracle 数据库 -->
		<!-- <environment id="oracle"></environment> -->
		
	</environments>
	
	<!-- 配置Mapper.xml文件 -->
	<mappers>
		<mapper resource="com/course/mapper/UserMapper.xml" />
	</mappers>
	
</configuration>

新建User

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package com.course.vo;

import java.util.Date;

public class User {

	private Integer id;
	private String name;
	private Integer age;
	private String address;
	private Date birthday;
	
	public User() {
		super();
	}
	
	public User(String name, Integer age, String address, Date birthday) {
		super();
		this.name = name;
		this.age = age;
		this.address = address;
		this.birthday = birthday;
	}

	public User(Integer id, String name, Integer age, String address, Date birthday) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.address = address;
		this.birthday = birthday;
	}

	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	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 String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

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

新建Mapper.xml

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<?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的namespace只是用来标识该mapper，与接口名及其实现类名没有关系 -->
<mapper namespace="com.course.dao.abc.UserDao">
	<insert id="addUserXml" parameterType="com.course.vo.User">
		insert into user(name, age, address, birthday) 
			values(#{name}, #{age}, #{address}, #{birthday})
	</insert>
	
	<update id="updateUser" parameterType="com.course.vo.User">
		update user set name=#{name}, age=#{age}, address=#{address}, birthday=#{birthday}
			where id=#{id}
	</update>
	
	<delete id="deleteUser" parameterType="int">
		delete from user 
			where id=#{val}
	</delete>
	
	<select id="getUserById" parameterType="int" resultType="com.course.vo.User">
		select * from user where id=#{val}
	</select>
	
	<select id="getAllUser" resultType="com.course.vo.User">
		select * from user
	</select>
</mapper>

新建接口UserDao

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package com.course.dao;

import java.util.List;

import com.course.vo.User;

public interface UserDao {

	public void addUser(User user);
	
	public void updateUser(User user);
	
	public void deleteUser(Integer id);
	
	public User getUserById(Integer id);
	
	public List<User> getAllUser();
	
}

新建接口的实现类

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package com.course.dao.impl;

import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import com.course.dao.UserDao;
import com.course.vo.User;

public class UserDaoImpl implements UserDao {

	@Override
	public void addUser(User user) {
		// 1.得到mybtais.cfg.xml的配置文件
		InputStream inputStream = this.getClass().getResourceAsStream("/mybatis.cfg.xml");
		// 2.得到SqlSessionFactoryBuilder
		SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
		// 3.sqlSessionFactoryBuilder去构造SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);
		// 4.从SqlSessionFactory得到sqlSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		// 5.进行CRUD 
		/**
		 * 参数1: 对应的是UserMapper.xml的命名空间值+<insert>节点的id属性值
		 * 参数2: UserMapper.xml里面<insert id="参数1">的parameterType属性对应的类型的对象
		 */
		sqlSession.insert("com.course.dao.abc.UserDao.addUserXml", user);
		// 6.提交事务
		sqlSession.commit();
		// 7.关闭session
		sqlSession.close();

	}

	@Override
	public void updateUser(User user) {
		// 1.得到mybtais.cfg.xml的配置文件
		InputStream inputStream = this.getClass().getResourceAsStream("/mybatis.cfg.xml");
		// 2.得到SqlSessionFactoryBuilder
		SqlSessionFactoryBuilder sessionFactoryBuilder = new SqlSessionFactoryBuilder();
		// 3.sqlSessionFactoryBuilder去构造SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = sessionFactoryBuilder.build(inputStream);
		// 4.从SqlSessionFactory得到sqlSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		// 5.进行CRUD 
		sqlSession.update("com.course.dao.abc.UserDao.updateUser", user);
		// 6.提交事务
		sqlSession.commit();
		// 7.关闭sqlSession
		sqlSession.close();

	}

	@Override
	public void deleteUser(Integer id) {
		// 1.得到mybtais.cfg.xml的配置文件
		InputStream inputStream = this.getClass().getResourceAsStream("/mybatis.cfg.xml");
		// 2.得到SqlSessionFactoryBuilder
		SqlSessionFactoryBuilder sessionFactoryBuilder = new SqlSessionFactoryBuilder();
		// 3.sqlSessionFactoryBuilder去构造SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = sessionFactoryBuilder.build(inputStream);
		// 4.从SqlSessionFactory得到sqlSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		// 5.进行CRUD 
		sqlSession.delete("com.course.dao.abc.UserDao.deleteUser", id);
		// 6.提交事务
		sqlSession.commit();
		// 7.关闭sqlSession
		sqlSession.close();

	}

	@Override
	public User getUserById(Integer id) {
		// 1.得到mybtais.cfg.xml的配置文件
		InputStream inputStream = this.getClass().getResourceAsStream("/mybatis.cfg.xml");
		// 2.得到SqlSessionFactoryBuilder
		SqlSessionFactoryBuilder sessionFactoryBuilder = new SqlSessionFactoryBuilder();
		// 3.sqlSessionFactoryBuilder去构造SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = sessionFactoryBuilder.build(inputStream);
		// 4.从SqlSessionFactory得到sqlSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		// 5.进行CRUD 
		User user = sqlSession.selectOne("com.course.dao.abc.UserDao.getUserById", id);
		// 6.提交事务
		sqlSession.commit();
		// 7.关闭sqlSession
		sqlSession.close();
		
		return user;
	}

	@Override
	public List<User> getAllUser() {
		// 1.得到mybtais.cfg.xml的配置文件
		InputStream inputStream = this.getClass().getResourceAsStream("/mybatis.cfg.xml");
		// 2.得到SqlSessionFactoryBuilder
		SqlSessionFactoryBuilder sessionFactoryBuilder = new SqlSessionFactoryBuilder();
		// 3.sqlSessionFactoryBuilder去构造SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = sessionFactoryBuilder.build(inputStream);
		// 4.从SqlSessionFactory得到sqlSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		// 5.进行CRUD 
		List<User> userList = sqlSession.selectList("com.course.dao.abc.UserDao.getAllUser");
		// 6.提交事务
		sqlSession.commit();
		// 7.关闭sqlSession
		sqlSession.close();
		
		return userList;
	}
}

新建测试类

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package com.course.test;

import java.util.List;

import com.course.dao.UserDao;
import com.course.dao.impl.UserDaoImpl;
import com.course.vo.User;

public class MainTest {

	public static void main(String[] args) {
		
		UserDao userDao = new UserDaoImpl();
		
//		User user1 = new User("user1", 10, "address1", new Date());
//		User user2 = new User("user2", 10, "address2", new Date());
//		User user3 = new User("user3", 10, "address3", new Date());
//		userDao.addUser(user1);
//		userDao.addUser(user2);
//		userDao.addUser(user3);
		
//		User user2 = new User(2, "user2", 10, "address2", new Date());
//		userDao.updateUser(user2);
		
//		userDao.deleteUser(10);
		
//		User user2 = userDao.getUserById(2);
//		System.out.println(user2.toString());
		
		List<User> userList = userDao.getAllUser();
		for (User user : userList) {
			System.out.println(user.toString());
		}	
	}	
}
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User [id=1, name=user1, age=10, address=address1, birthday=Fri Aug 13 12:35:22 CST 2021]
User [id=2, name=user2, age=10, address=address2, birthday=Fri Aug 13 16:51:11 CST 2021]
User [id=4, name=user1, age=10, address=address1, birthday=Fri Aug 13 16:55:22 CST 2021]
User [id=5, name=user2, age=10, address=address2, birthday=Fri Aug 13 16:55:22 CST 2021]
User [id=7, name=user1, age=10, address=address1, birthday=Fri Aug 13 16:57:01 CST 2021]
User [id=8, name=user2, age=10, address=address2, birthday=Fri Aug 13 16:57:01 CST 2021]
User [id=9, name=user3, age=10, address=address3, birthday=Fri Aug 13 16:57:01 CST 2021]
User [id=11, name=user11, age=10, address=address11, birthday=Fri Aug 13 16:58:27 CST 2021]
User [id=12, name=user12, age=10, address=address2, birthday=Mon Aug 16 15:54:29 CST 2021]
User [id=14, name=user3, age=10, address=address3, birthday=Mon Aug 16 15:53:30 CST 2021]

直接执行sql操作的是mapper.xml，Dao接口及其实现类只是使用mybatis的方法调用mapper.xml执行sql操作，Dao接口及其实现类与mapper.xml没有直接的关系。