使用IDEA、Mybatis配置的sql数据库的增删改查（优化后）

本文链接：https://blog.youkuaiyun.com/NewBeeMu/article/details/100127554

本文详细介绍了如何在IntelliJ IDEA中配置并使用Mybatis进行数据库的增删改查操作，包括pom.xml配置、Mybatis配置文件、日志配置、数据库连接属性设置、Mapper接口和XML映射文件、启动类以及DAO接口和实现类的编写。通过这个过程，读者可以学习到一套完整的Mybatis集成和优化实践。

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pom.xml：

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>text</groupId>
  <artifactId>Mybatis</artifactId>
  <version>1.0.0</version>
  <packaging>jar</packaging>

  <dependencies>
    <!--mybatis依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.6</version>
    </dependency>

    <!--链接mysql的驱动-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.38</version>
    </dependency>

    <!--junit单元测试-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>

    <!--lombok-->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.16.20</version>
      <scope>provided</scope>
    </dependency>

    <!--log4j日志-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.25</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.25</version>
      <scope>test</scope>
    </dependency>



  </dependencies>

</project>

Mybatis.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>
    <!--属性配置
        resource：从classes文件夹开始寻找文件
    -->
    <properties resource="db.properties"/>
    <!--配置别名-->
    <typeAliases>
        <!--配置单个对象的别名-->
        <!--<typeAlias type="text.Mybatis.bean.User" alias="User"/>-->
        <!--
            配置包，整个包下面的类都会被注册别名
            默认情况下，别名为简单类名，且大小写不敏感
        -->、
        <package name="text.Mybatis.bean"/>
    </typeAliases>
    <!--配置环境
        defauilt：mybatis启动时使用的哪个环境
    -->
    <environments default="development">
        <environment id="development">
            <!--事务管理器
                使用mysql的事务管理器来管理事务
            -->
            <transactionManager type="JDBC"/>
            <!--数据源-->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--关联映射文件-->
    <mappers>
        <!--resource从classes文件夹中寻找文件-->
        <mapper resource="text/Mybatis/dao/UserMapper.xml"></mapper>
    </mappers>
</configuration>

log4j.properties：

# Global logging configuration
log4j.rootLogger=ERROR, stdout
# MyBatis logging configuration...
log4j.logger.org.mybatis.example.BlogMapper=TRACE
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

db.properties：

diver=com.mysql.jdbc.Driver
url=jjdbc:mysql:///mybatis
value=root
password=123

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">
<!--
    映射文件通常和dao接口放在同一个包中
-->
<!--
    namespace的值通常为dao接口的全限定名
-->
<mapper namespace="text.Mybatis.dao.IUserDao">
<!--
    定义一个结果映射
    id：结果映射的唯一标识
    type：封装成哪个类的对象
-->
    <resultMap id="userResultMap" type="text.Mybatis.bean.User">
        <!--<result column=”数据库中的列名” property=”想要展示的属性名”/>（可以一样）（主键可以改,以id为例）-->
        <id column="id" property="id"/>
        <result column="name" property="name"/>
        <result column="age" property="age"/>
        <result column="birthday" property="birthday"/>
        <result column="salary" property="salalry"/>
    </resultMap>
<!--
    useGeneratedKeys：要获取mysql数据库自动生成的主键，默认值为false，当赋值为true时，则代表开始获取
    keyProperty：把获取到的主键，设置给对象的哪个属性
    keyColumn：从哪个列获取到的自动生成的主键的值（可以省略）
-->

    <insert id="save" useGeneratedKeys="true" keyProperty="id" keyColumn="id">
        insert into user(name,age,birthday,salary)
        VALUES (#{name},#{age},#{birthday},#{salary})
    </insert>

    <update id="update">
        update user set
        name=#{name},
        age=#{age},
        birthday=#{birthday},
        salary=#{salary}
        WHERE
        id=#{id}
    </update>

    <delete id="delete">
        delete from user where id=#{id}
    </delete>

    <!--<select id="get" resultType="User">-->
    <!--使用结果映射，就不用resultType，而用resultMap-->
    <select id="get" resultMap="userResultMap">
        select * from user where id=#{id}
    </select>
    
    <select id="list" resultType="User">
        select * from user
    </select>

</mapper>

App.java：

import text.Mybatis.bean.User;
import text.Mybatis.dao.IUserDao;
import text.Mybatis.dao.impl.UserDaoImpl;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import org.apache.ibatis.io.Resources;

import java.io.IOException;
import java.io.InputStream;
import java.math.BigDecimal;
import java.util.Date;

/**
 * Created by Administrator on 2019/8/28.
 */

public class App {
    @Test
    public void testSqlSessionFactory() throws Exception {

        //获取SQLSessionFactory对象
        String resource="Mybatis.xml";
        InputStream in = Resources.getResourceAsStream(resource);

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession session = sqlSessionFactory.openSession();

        System.out.println(sqlSessionFactory);

    }

    @Test
    public void testSave() throws Exception {
        IUserDao dao=new UserDaoImpl();
        User user=new User(null,"jack",20,new Date(1000),new BigDecimal(3000.00));
        dao.save(user);
    }

    @Test
    public void testUpdate() throws Exception {
        IUserDao dao=new UserDaoImpl();
        User user=new User(2,"tom",30,new Date(),new BigDecimal(5000.00));
        dao.update(user);
    }
    @Test
    public void testDelete() throws Exception {
        IUserDao dao=new UserDaoImpl();
        dao.delete(2);

    }
    @Test
    public void testGet() throws Exception {
        IUserDao dao=new UserDaoImpl();
        System.out.println(dao.get(1));

    }
    @Test
    public void testList() throws Exception {
        IUserDao dao=new UserDaoImpl();
        System.out.println(dao.list());

    }
}

MybatisUtil.java：

package text.Mybatis.util;

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

/**
 * Created by Administrator on 2019/8/28.
 */
public class MybatisUtil {
    public static SqlSessionFactory factory=null;
    static {
        String resource="Mybatis.xml";
        InputStream in = null;
        try {
            in = Resources.getResourceAsStream(resource);
        } catch (IOException e) {
            e.printStackTrace();
        }

        factory = new SqlSessionFactoryBuilder().build(in);
    }

    public static SqlSession getsession (){

        return factory.openSession();
    }


}

IUserDao.java（接口）：

package text.Mybatis.dao;

import text.Mybatis.bean.User;

import java.util.List;

/**
 * Created by Administrator on 2019/8/28.
 */
public interface IUserDao {
    void save(User user);
    void update(User user);
    void delete(Integer id);

    User get(Integer id);
    List<User> list();
}

UserDaoImpl.java：

package text.Mybatis.dao.impl;

import text.Mybatis.bean.User;
import text.Mybatis.dao.IUserDao;
import text.Mybatis.util.MybatisUtil;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * Created by Administrator on 2019/8/28.
 */
public class UserDaoImpl implements IUserDao{

    public void save(User user) {
        //执行保存操作
//        获取SqlSession对象
        SqlSession session = MybatisUtil.getsession();
//        执行保存的sql语句
//        namespace的值加上id值
        session.insert("text.Mybatis.dao.IUserDao.save",user);
//        提交事务
        session.commit();
//        关闭session
        session.close();
    }
//  更新操作
    public void update(User user) {
        SqlSession session = MybatisUtil.getsession();
        session.update("text.Mybatis.dao.IUserDao.update",user);
        session.commit();
        session.close();

    }

    public void delete(Integer id) {
        SqlSession session = MybatisUtil.getsession();
        session.delete("text.Mybatis.dao.IUserDao.delete",id);
        session.commit();
        session.close();
    }

    public User get(Integer id) {
        SqlSession session = MybatisUtil.getsession();
//        查询一个
        User user = (User) session.selectOne("text.Mybatis.dao.IUserDao.get", id);

        session.commit();
        session.close();

        return user;

    }

    public List<User> list() {
        SqlSession session = MybatisUtil.getsession();
//        查询列表
        List<User> list = session.selectList("text.Mybatis.dao.IUserDao.list");

        session.commit();
        session.close();

        return list;


    }
}

User.java：

package text.Mybatis.bean;

import lombok.*;
import org.apache.ibatis.type.Alias;

import java.math.BigDecimal;
import java.util.Date;

/**
 * Created by Administrator on 2019/8/28.
 */
@Setter@Getter@ToString
@AllArgsConstructor
@NoArgsConstructor
//可以使用注解显示的配置某个类的别名
@Alias("myUser")
public class User {
    private Integer id;
    private String name;
    private Integer age;
    private Date birthday;
    private BigDecimal salary;
}