SpringBoot整合Mybatis

朱雀 2021-08-29 23:55 533阅读 0赞

## SpringBoot整合Mybatis ##

### 1、通过Maven构建SpringBoot项目（IDEA） ###

在IDEA里如何通过Maven构建SpringBoot项目：https://blog.csdn.net/weixin\_45747080/article/details/106086408

### 2、对应表中字段编写pojo类 ###

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其中uid自增

User.java：

@Component
    public class User { 
        private int uid;
        private String username;
        private String password;
        private int age;
    
        public User() { 
        }
    
        public User(int uid, String username, String password, int age) { 
            this.uid = uid;
            this.username = username;
            this.password = password;
            this.age = age;
        }
    
        @Override
        public String toString() { 
            return "User{" +
                    "uid=" + uid +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    ", age=" + age +
                    '}';
        }
    
        public int getUid() { 
            return uid;
        }
    
        public void setUid(int uid) { 
            this.uid = uid;
        }
    
        public String getUsername() { 
            return username;
        }
    
        public void setUsername(String username) { 
            this.username = username;
        }
    
        public String getPassword() { 
            return password;
        }
    
        public void setPassword(String password) { 
            this.password = password;
        }
    
        public int getAge() { 
            return age;
        }
    
        public void setAge(int age) { 
            this.age = age;
        }
    }

记得加上`@Component`注解把他交给Spring去管理

### 3、根据需求写Mapper接口 ###

看需求：

用户注册
    用户登录
    查询用户
    修改用户

UserMapper.java：

@Mapper
    @Repository
    public interface UserMapper { 
        //新增用户
        int insertUser(User user);
        //根据用户名和密码查询用户
        User selectUserByUsernameAndPassword(User user);
        //查询所有用户
        List<User> selectAllUser();
        //修改用户
        int updateUser(User user);
    }

注册实质上就是新增用户，登录实质上就是根据用户名和密码查询用户，记得不要忘了加`@Mapper @Repository`注解，表示他是Mapper交给Spring托管并且属于Dao层

### 4、对应的Mapper.xml文件 ###

<?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="cn.wqk.springboot07.mapper.UserMapper">
        <insert id="insertUser" keyProperty="uid" useGeneratedKeys="true">
            INSERT INTO
                user
            (username,password,age)
            VALUES
            (#{username},#{password},#{age})
        </insert>
        <select id="selectUserByUsernameAndPassword" parameterType="User" resultType="User">
            SELECT
                *
            FROM
                user
            WHERE
                username=#{username}
                AND password=#{password}
        </select>
        <select id="selectAllUser" resultType="User">
            SELECT
                *
            FROM
                user
        </select>
        <update id="updateUser" parameterType="User">
            UPDATE
                user
            <trim prefix="SET" suffixOverrides=",">
                <if test=" password!=null and password!='' ">
                    password=#{password},
                </if>
                <if test=" age!=null and age!='' ">
                    age=#{age},
                </if>
            </trim>
            WHERE
                uid=#{uid}
        </update>
    </mapper>

放到resources包下的mybatis下的mapper里

### 5、在配置文件里配置mybatis相关 ###

application.yaml:

#########################################################
    #数据源
    spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/um?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
        username: root
        password:
    #########################################################
    
    
    #########################################################
    #Mybatis相关配置
    mybatis:
      type-aliases-package: cn.wqk.springboot07.pojo
      mapper-locations: mybatis/mapper/*Mapper.xml
    #########################################################

### 6、service业务层 ###

依旧是对mapper增删改查出来的东西进行进一步封装。

UserService.java:

@Service
    public interface UserService { 
        //注册用户，true注册成功，false注册失败
        boolean registerUser(User user);
        //用户登录，true登录成功，false登录失败
        boolean login(User user);
        //查询所有用户
        List<User> selectAllUser();
        //修改用户信息，true修改成功，false修改失败
        boolean updateUser(User user);
    }

记得加上`@Service`注解

然后写service接口的具体实现：

UserServiceImpl:

@Service
    public class UserServiceImpl implements UserService{ 
        @Autowired
        private UserMapper userMapper;
        @Override
        public boolean registerUser(User user) { 
            int i = userMapper.insertUser(user);
            if (i>0){ 
                //新增用户成功
                return true;
            }else { 
                //新增用户失败
                return false;
            }
        }
    
        @Override
        public boolean login(User user) { 
            User user1 = userMapper.selectUserByUsernameAndPassword(user);
            if (user1!=null){ 
                //查询到该用户
                return true;
            }else { 
                //未查询到该用户
                return false;
            }
        }
    
        @Override
        public List<User> selectAllUser() { 
            return userMapper.selectAllUser();
        }
    
        @Override
        public boolean updateUser(User user) { 
            int i = userMapper.updateUser(user);
            if (i>0){ 
                //修改用户成功
                return true;
            }else { 
                //修改用户失败
                return false;
            }
        }
    }

同样也要加上`@Service`注解把他们两个都交给Spring容器去管理

### 7、控制器Controller ###

获得请求然后处理响应业务并且返回结果,既然只是用于测试我们就返回一个简单的JSON字符串好了。记得加上`@RestController`，因为我们把UserService和User都丢到了pojo里，所以就可以直接用`@Autowired`自动装配了。关于Controller控制器的写法和笔记：https://blog.csdn.net/weixin\_45747080/article/details/106026230

@RestController
    @RequestMapping("json")
    public class JSONController { 
        @Autowired
        private UserService userService;
        @Autowired
        private User user;
        @RequestMapping("/j1")
        public String j1(){ 
            return "helloJSON!";
        }
        @RequestMapping("/register")
        public String register(@RequestParam("name") String username,
                               @RequestParam("passWord") String password){ 
            user.setUsername(username);
            user.setPassword(password);
            boolean b = userService.registerUser(user);
            if (b){ 
                return "注册成功用户名是"+user.getUsername();
            }else { 
                return "注册失败";
            }
        }
        @RequestMapping("/login")
        public String login(@RequestParam("userName") String username,
                            @RequestParam("passWord") String password){ 
            user.setUsername(username);
            user.setPassword(password);
            boolean b = userService.login(user);
            if (b){ 
                return "登录成功，您的用户名是"+user.getUsername();
            }else { 
                return "登录失败";
            }
        }
        @RequestMapping("/allUser")
        public String allUser(){ 
            List<User> userList = userService.selectAllUser();
            String s = JSON.toJSONString(userList);
            return s;
        }
        @RequestMapping("/updateUser")
        public String updateUser(@RequestParam("user") User user){ 
            boolean b = userService.updateUser(user);
            if (b){ 
                return "修改成功，修改后的密码是"+user.getPassword();
            }else { 
                return "登录失败";
            }
        }
    }

然后在浏览器的地址栏输入相应的请求就能返回对应的JSON字符串了。

### 8、前端页面 ###

前端我用的thymeleaf模板引擎，并没有使用MVC里的jsp页面。我只需要在前端相应的表单或者地址栏发起请求，就能得到相应的数据了。

### 9、测试 ###

最后运行位于项目目录下的Application主方法

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTc0NzA4MA_size_16_color_FFFFFF_t_70]

然后到浏览器测试登录：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTc0NzA4MA_size_16_color_FFFFFF_t_70 1]

登录成功：

![在这里插入图片描述][20200512221708801.png]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTc0NzA4MA_size_16_color_FFFFFF_t_70 2]

注册成功：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTc0NzA4MA_size_16_color_FFFFFF_t_70 3]

查询所有用户：

![在这里插入图片描述][20200512221737830.png]

修改用户：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTc0NzA4MA_size_16_color_FFFFFF_t_70 4]

### 10、文件目录架构 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTc0NzA4MA_size_16_color_FFFFFF_t_70 5]

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