【MyBatis框架】实现增删改查功能

CSDN话题挑战赛第2期
参赛话题：学习笔记

1. MyBatis流程回顾

上一篇中我们已经了解了MyBatis框架的基本实现，现在先来回顾一下其实现流程

2. 工具类的构建

观察上述步骤，我们发现每次都需要通过SqlSessionFactoryBuilder构建SqlSessionFactory然后再获得SqlSession对象，这些步骤都是相同的，我们可以把它们封装成为一个工具类MybatisUtils

package com.zxy.mybatis.Utils;

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;

public class MybatisUtils {
    public static SqlSession getSqlSession() throws IOException {
        //读取MyBatis的核心配置文件
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        //创建SqlSessionFactoryBuilder对象
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new
                SqlSessionFactoryBuilder();
        //通过核心配置文件所对应的字节输入流创建工厂类SqlSessionFactory，生产SqlSession对象
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        //创建SqlSession对象，此时通过SqlSession对象所操作的sql都必须手动提交或回滚事务
        //SqlSession sqlSession = sqlSessionFactory.openSession();
        //创建SqlSession对象，此时通过SqlSession对象所操作的sql都会自动提交
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        return sqlSession;
    }
}

3. 相关各类配置

1. 实体类User

package com.zxy.mybatis.pojo;

public class User {
    private Integer id;
    private String username;
    private String psd;
    private Integer age;
    private String gender;
    private String email;

    public User() {
    }

    public User(Integer id, String username, String psd, Integer age, String gender, String email) {
        this.id = id;
        this.username = username;
        this.psd= psd;
        this.age = age;
        this.gender = gender;
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", psd='" + psd+ '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                ", email='" + email + '\'' +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPsd() {
        return psd;
    }

    public void setPsd(String psd) {
        this.psd= psd;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

2. UserMapper

package com.zxy.mybatis.mapper;

import com.zxy.mybatis.pojo.User;

import java.util.List;

public interface UserMapper {
    /**
     * 添加用户信息
     */
    int insertUser();
    int deleteUser();
    int updateUser();
    User getUserById();

}

3. 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.zxy.mybatis.mapper.UserMapper">
    <!--int insertUser();-->
    <insert id="insertUser">
        insert into t_user values(null,'bobo','123456',23,'男','12345@qq.com')
    </insert>
    <!--int deleteUser();-->
    <delete id="deleteUser" >
        delete from t_user where id = 1
    </delete>
    <!--int updateUser();-->
    <update id="updateUser" >
        update t_user set username='zxy',password='123' where id = 6
    </update>
    <!--User getUserById();-->
    <select id="getUserById" resultType="com.zxy.mybatis.pojo.User">
        select * from t_user where id = 1
    </select>
</mapper>

4. 增加数据功能

首先在UserMapper中写入方法

int insertUser();

配置Mapper接口

 <!--int insertUser();-->
    <insert id="insertUser">
        insert into t_user values(null,'bobo','123456',23,'男','12345@qq.com')
    </insert>

执行方法测试

查看结果

返回值表明已经成功，我们查看数据库进一步确认

加入成功

5. 删除数据功能

首先在UserMapper中写入方法

配置Mapper接口

 <!--int deleteUser();-->
    <delete id="deleteUser" >
        delete from t_user where id = 9
    </delete>

执行方法测试

结果如下

查看数据库是否成功

可以发现id为9的已经被删除

6. 修改数据功能

首先在UserMapper中写入方法

配置UserMapper

 <!--int updateUser();-->
    <update id="updateUser" >
        update t_user set username='zxy',password='123' where id = 7
    </update>

执行方法测试

结果如下

查看数据库

id为6的那个数据确实已经发生改变

7. 查询数据功能

首先在UserMapper中写入方法

配置UserMapper

<!--User getUserById();-->
    <select id="getUserById" resultType="com.zxy.mybatis.pojo.User">
        select * from t_user where id = 7
    </select>

执行方法测试

结果如下，表明查询成功