1. 构建项目：

2.添加依赖

    <dependencies>        
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.7</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

3.Model 准备

public interface UserService {
    User login(String usrName, String usrPassword);
    int addUser(User user);
    int deleteUser(Long usrId);
    int updateUser(User user);
    User getUser(Long usrId);
    List<User> findAllUsers();
}

5.2 控制器开发

5.2.1 JSON的支持

@Controller
public class UserController {
    @Resource
    private UserService userService;

    @RequestMapping(value = "/getUser",method = RequestMethod.GET)
    public User getUser(Long usrId){
        User user = userService.getUser(usrId);
        return user;
    }
}