SSM16.2【Mybatis：通过注解实现Mybatis的简单增删改查】

注解方式实现Mybatis的增删改查

 

 

 

 

 

 

 

 

 

 

<?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">

<!--The content of element type "configuration" must match
"(properties?,settings?,typeAliases?,typeHandlers?,objectFactory?,
objectWrapperFactory?,reflectorFactory?,plugins?,environments?,databaseIdProvider?,mappers?)".-->

<configuration>

    <!--加载外部properties文件-->
    <properties resource="jdbc.properties"></properties>

    <!--自定义别名-->
    <typeAliases>
        <typeAlias type="com.haifei.domain.User" alias="user" />
    </typeAliases>

    <!--注册类型处理器-->
    <typeHandlers>
        <typeHandler handler="com.haifei.handler.DateTypeHandler" />
    </typeHandlers>

    <environments default="development">
        <!--配置数据源环境-->
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <!--xml实现mybatis-CRUD：加载映射文件-->
    <!--<mappers>
        <mapper resource="com/haifei/mapper/UserMapper.xml"/>
    </mappers>-->

    <!--注解实现mybatis-CRUD：加载映射关系-->
    <mappers>
        <!--指定接口所在的包，扫包-->
        <package name="com.haifei.mapper"></package>
    </mappers>


</configuration>

package com.haifei.mapper;

import com.haifei.domain.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

/**
 * 注意：使用注解进行mybatis-CRUD时，必须将resources下的mapper.xml删掉，不然报错
 */
public interface UserMapper {

    @Insert("insert into user values(#{id},#{username},#{password},#{birthday})")
    public void save(User user);

    @Delete("delete from user where id=#{id}")
    public void delete(int id);

    @Update("update user set username=#{username},password=#{password},birthday=#{birthday} where id=#{id}")
    public void update(User user);

    @Select("select * from user")
    public List<User> findAll();

    @Select("select * from user where id=#{id}")
    public User findById(int id);

}

package com.haifei.test;

import com.haifei.domain.User;
import com.haifei.mapper.UserMapper;
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 org.junit.Before;
import org.junit.Test;

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

public class MybatisTest {

    private UserMapper mapper;

    @Before
    public void before() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession(true); //true-->事务自动提交
        mapper = sqlSession.getMapper(UserMapper.class);
    }

    @Test
    public void testSave(){
        User user = new User();
        user.setUsername("222");
        user.setPassword("222");
        user.setBirthday(new Date());
        mapper.save(user);
        //Updates: 1
    }

    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(12);
        user.setUsername("333");
        user.setPassword("333");
        user.setBirthday(new Date());
        mapper.update(user);
        //Updates: 1
    }

    @Test
    public void testDelete(){
        mapper.delete(12);
        //Updates: 1
    }

    @Test
    public void testFindAll(){
        List<User> userList = mapper.findAll();
        for (User user : userList) {
            System.out.println(user);
        }
        /*
        User{id=1, username='zhangsan', password='123', birthday=Sat Jul 24 20:00:29 CST 2021}
        User{id=2, username='lisi', password='345', birthday=Sat Jul 24 20:00:29 CST 2021}
        User{id=3, username='tom', password='abc', birthday=Sat Jul 24 20:00:29 CST 2021}
        User{id=4, username='lucy', password='def', birthday=Sat Jul 24 20:00:29 CST 2021}
        User{id=5, username='sam', password='sam', birthday=Sat Jul 24 20:00:29 CST 2021}
        User{id=9, username='11', password='11', birthday=Sat Jul 24 20:00:29 CST 2021}
         */
    }

    @Test
    public void testFindById(){
        User user = mapper.findById(5);
        System.out.println(user); //User{id=5, username='sam', password='sam', birthday=Sat Jul 24 20:00:29 CST 2021}
    }

}