Mybatis实现简单增删改查备用（Intellij idea）

环境

Intellij idea
MySQL

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环境搭建及依赖

依赖引入

1.mybatis                 mybatis包
2.mysql-connector-java    mysql数据库JDBC驱动

配置文件

1.pom.xml                 maven配置文件
2.mybatis-config.xml      mybatis配置文件
3.characterMapper.xml     mybatis里的mapper映射配置文件。名字自己起的。

接口

characterMapper           mybatis里只需要定义接口，会动态为我们生成实现类

表格

historycharacter          

entity实体类

HistoryCharacter.java     类属性对应historycharacter表格的一条记录

工具类

MybatisUtil.java           非必须这么区分，这里只是为了使程序更清晰

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目录结构

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整体过程

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pom.xml

<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>4.0.0modelVersion>

    <groupId>com.zsbgroupId>
    <artifactId>mybatisartifactId>
    <version>1.0.0version>

    <dependencies>
        
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.4.5version>
        dependency>
        
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.41version>
        dependency>
    dependencies>
project>

#

<configuration>
    
    <properties>
        <property name="driver" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/zsb" />
        <property name="username" value="root" />
        <property name="password" value="123456" />
    properties>
    <environments default="development">
        
        <environment id="development">
            <transactionManager type="JDBC" />
            
            <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>
    <mappers>
        <mapper resource="characterMapper.xml"/>
    mappers>
configuration>

characterMapper.xml

<mapper namespace="com.zsb.mapper.CharacterMapper">
    
    <insert id="incCharacter" parameterType="com.zsb.entity.HistoryCharacter" useGeneratedKeys="true" keyProperty="id" >
        INSERT  INTO historycharacter(firstname,occupation,story) VALUES (#{firstname},#{occupation},#{story})
    insert>
    
    <delete id="deleteCharacter" parameterType="int" >
        DELETE FROM historycharacter WHERE id = #{id}
    delete>
    
    <update id="updateCharacter" parameterType="com.zsb.entity.HistoryCharacter">
        UPDATE  historycharacter SET firstname = #{firstname}, occupation = #{occupation}, story = #{story} WHERE  id = #{id}
    update>
    
    <select id="getCharacter" parameterType="int" resultType="com.zsb.entity.HistoryCharacter">
        select * from historycharacter WHERE id= #{id}
    select>
mapper>

CharacterMapper.java

只需要提供接口方法即可。

package com.zsb.mapper;

import com.zsb.entity.HistoryCharacter;

public interface CharacterMapper {
    HistoryCharacter getCharacter(int id);
    void deleteCharacter(int id);
    void incCharacter(HistoryCharacter historyCharacter);
    void updateCharacter(HistoryCharacter historyCharacter);
}

HistoryCharacter.java

对应的实体类，这里的名字我设置成了与数据库一致。实际上，数据库有数据库的命名规则，假如按照数据库的规则写字段，java类的属性命名也按照java规则，也可以进行设置后自动转换。这就是规范的魅力。

package com.zsb.entity;

public class HistoryCharacter {
    private int id;
    private String firstname;
    private String occupation;
    private String story;
    public int getId() { return id;}
    public void setId(int id) {this.id = id;}
    public String getName() {return firstname;}
    public void setName(String firstname) { this.firstname = firstname;}
    public String getOccupation() { return occupation;}
    public void setOccupation(String occupation) { this.occupation = occupation;}
    public String getStory() {return story;}
    public void setStory(String story) {this.story = story;}
    @Override
    public String toString() {
        return "HistoryCharacter{" +
                "id=" + id +
                ", name='" + firstname + '\'' +
                ", occupation='" + occupation + '\'' +
                ", story='" + story + '\'' +
                '}';
    }
}

MybatisUtil.java

package com.zsb.util;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

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

//需要返回一个SqlSessionFactroy对象
public class MybatisUtil {
    public static SqlSessionFactory getSqlSessionFactory(){
        String resources = "mybatis-config.xml";
        InputStream inputStream = null;
        //通过xml文件生成一个SqlSessionFactory对象
        //我们要借助输入流
        try {
            inputStream = Resources.getResourceAsStream(resources);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new SqlSessionFactoryBuilder().build(inputStream);
    }
}

表格

sql

CREATE TABLE historycharacter
(
  id         INT(20) AUTO_INCREMENT
    PRIMARY KEY,
  firstname  VARCHAR(20) NULL,
  occupation VARCHAR(30) NULL,
  story      TEXT        NULL
)
  ENGINE = InnoDB;

这里是Intellij idea里查看的样式

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测试

import com.zsb.mapper.CharacterMapper;
import com.zsb.entity.HistoryCharacter;
import com.zsb.util.MybatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

public class Main {
    public static void main(String[] args) {
        SqlSessionFactory sqlSessionFactory = null;
        //通过我们的工具类获得了SqlSessinoFactoryD对象
        sqlSessionFactory = MybatisUtil.getSqlSessionFactory();

        //获得SqlSession对象
        //自动提交：只需要在openSession方法上填上true即可。默认需要手动提交。
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //获得一个CharacterMapper接口的实例
        CharacterMapper characterMapper = sqlSession.getMapper(CharacterMapper.class);

        //查询数据
        //通过SqlSession对象，以及CharacterMapper接口，生成一个该接口的实例对象
        HistoryCharacter historyCharacter = sqlSession.getMapper(CharacterMapper.class).getCharacter(1);
        System.out.println(historyCharacter);

        //更新数据
        //HistoryCharacter historyCharacter2 = new HistoryCharacter();
        //historyCharacter2.setId(1);
        //historyCharacter2.setName("刘备");
        //historyCharacter2.setOccupation("蜀国主公");
        //historyCharacter2.setStory("三英战吕布");
        //sqlSession.getMapper(CharacterMapper.class).updateCharacter(historyCharacter2);
        //System.out.println(historyCharacter2);

        //增加数据
        //HistoryCharacter historyCharacter2 = new HistoryCharacter();
        //historyCharacter2.setId(1);
        //historyCharacter2.setName("关羽");
        //historyCharacter2.setOccupation("蜀国大将");
        //historyCharacter2.setStory("三英战吕布，水淹七军");
        //characterMapper.incCharacter(historyCharacter2);

        //删除数据
        //characterMapper.deleteCharacter(4);

        //手动提交更改    
        sqlSession.commit();
    }
}

测试结果

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总结

多总结，才能记得住。
这个测试很简陋，不过主要是为了记住这种思想过程。留待日后查看备忘