【MyBatis框架】实现增删改查功能

╰+攻爆jí腚メ 2024-04-03 10:01 119阅读 0赞

[CSDN话题挑战赛第2期][CSDN_2]  
参赛话题：[学习笔记][Link 1]

#### 目录 ####

*   *   *  1. MyBatis流程回顾
         *  2. 工具类的构建
         *  3. 相关各类配置
         *  4. 增加数据功能
         *  5. 删除数据功能
         *  6. 修改数据功能
         *  7. 查询数据功能

#### 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

![在这里插入图片描述][d55e6363585e44a1a5a1725c36cce937.png]

#### 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`

![在这里插入图片描述][f15d35107ce04f9f989646410310eefe.png]

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;
        }
    }

1.  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();
    
    }

1.  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">
        
        <insert id="insertUser">
            insert into t_user values(null,'bobo','123456',23,'男','12345@qq.com')
        </insert>
        
        <delete id="deleteUser" >
            delete from t_user where id = 1
        </delete>
        
        <update id="updateUser" >
            update t_user set username='zxy',password='123' where id = 6
        </update>
        
        <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

![在这里插入图片描述][2d6933706df94d45a6bef0d956358daa.png]

int insertUser();

配置Mapper接口

![在这里插入图片描述][cd8635b8e28240b2b580951e76bd6e8a.png]

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

执行方法测试  
![在这里插入图片描述][723d9f85e10c45f9a3841d4d0b682efb.png]

查看结果

![在这里插入图片描述][bc3386039a0c4179b0155cdac76ea525.png]

返回值表明已经成功，我们查看数据库进一步确认

![在这里插入图片描述][189c210b05be4240a4eaad4a5fa646a1.png]

加入成功

#### 5. 删除数据功能 ####

首先在UserMapper中写入方法

![在这里插入图片描述][7f34ec2bc1f2459aa46bf6802f058953.png]

配置Mapper接口  
![在这里插入图片描述][7b534ea2eb1f46dabe819d25b3ce3e93.png]

<delete id="deleteUser" >
            delete from t_user where id = 9
        </delete>

执行方法测试

![在这里插入图片描述][c0de27c21c6a416ab96529ed47b94a68.png]

结果如下

![在这里插入图片描述][1ef44f8ab3454bf58ff4fb3a952be3ca.png]

查看数据库是否成功

![在这里插入图片描述][ef548461c6224c17be9a0f3ff51bf525.png]

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

![在这里插入图片描述][99f75710cbf944d2a619f3453bddc180.png]

配置UserMapper

![在这里插入图片描述][0344b00d38f2443e9a78e3df71f5b9c9.png]

<update id="updateUser" >
            update t_user set username='zxy',password='123' where id = 7
        </update>

执行方法测试

![在这里插入图片描述][f4abb7c577754c20b2e5778a009dedaf.png]

结果如下

![在这里插入图片描述][0f6db96615ba4d6f9739c5fed15ff55e.png]

查看数据库  
![在这里插入图片描述][e75761ba0a3e466db7280ca3595c7eee.png]

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

![在这里插入图片描述][2b5619b1008e44d3a456dcd5e1f068f9.png]

配置UserMapper

![在这里插入图片描述][83be6a0e7d2540b58c7f8df4fa8f2f7f.png]

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

执行方法测试

![在这里插入图片描述][738a5132d9664d54955055e06c60f132.png]

结果如下，表明查询成功  
![在这里插入图片描述][245bc84879f348e59060db0efd50b455.png]

[CSDN_2]: https://marketing.csdn.net/p/7b6697fd9dd3795a268d1a6f2fe75012
[Link 1]: https://activity.csdn.net/creatActivity?id=10213
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