Springboot-后端统一返回接口+统一异常处理+后端参数校验

引入依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

目录结构

1.统一返回接口

1.1 统一响应体定义

package com.suruomo.unified.result;

import lombok.Getter;
import lombok.Setter;

/**
 * @author suruomo
 * @date 2020/8/7 15:36
 * @description: 自定义统一响应体
 * VO（ View Object）：显示层对象，通常是Web向模板渲染引擎层传输的对象。
 */
@Getter
@Setter
public class ResultVO<T> {
    /**
     * 状态码，比如1000代表响应成功
     */
    private int code;
    /**
     * 响应信息，用来说明响应情况
     */
    private String msg;
    /**
     * 响应的具体数据
     */
    private T data;

    public ResultVO(T data) {
        this(ResultCode.SUCCESS, data);
    }

    public ResultVO(ResultCode resultCode, T data) {
        this.code = resultCode.getCode();
        this.msg = resultCode.getMsg();
        this.data = data;
    }
}

1.2 枚举状态码定义

package com.suruomo.unified.result;

import lombok.Getter;

/**
 * @author suruomo
 * @date 2020/8/7 16:10
 * @description: 响应码枚举
 */
@Getter
public enum ResultCode {

    //1000系列通用错误
    SUCCESS(1000, "操作成功"),
    FAILED(1001, "接口错误"),
    VALIDATE_FAILED(1002, "参数校验失败"),
    ERROR(1003, "未知错误"),

    //2000系列用户错误
    USER_NOT_EXIST(2000,"用户不存在"),
    USER_LOGIN_FAIL(2001,"用户名或密码错误"),
    USER_NOT_LOGIN(2002,"用户还未登录,请先登录"),
    NO_PERMISSION(2003,"权限不足,请联系管理员");

    private int code;
    private String msg;

    ResultCode(int code, String msg) {
        this.code = code;
        this.msg = msg;
    }
}

2.实体类+参数校验

package com.suruomo.unified.pojo;

import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import javax.validation.constraints.Email;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

/**
 * @author suruomo
 * @date 2020/8/7 15:41
 * @description: 实体类
 */
@Getter
@Setter
@NoArgsConstructor
public class User {

    @NotNull(message = "用户id不能为空")
    private Long id;

    @NotNull(message = "用户账号不能为空")
    @Size(min = 6, max = 11, message = "账号长度必须是6-11个字符")
    private String account;

    @NotNull(message = "用户密码不能为空")
    @Size(min = 6, max = 11, message = "密码长度必须是6-16个字符")
    private String password;

    @NotNull(message = "用户邮箱不能为空")
    @Email(message = "邮箱格式不正确")
    private String email;
}

3.全局异常处理

3.1 自定义异常APIException

package com.suruomo.unified.exception;

import com.suruomo.unified.result.ResultCode;
import lombok.Getter;

/**
 * @author suruomo
 * @date 2020/8/7 16:43
 * @description: 自定义异常
 */
@Getter
public class APIException extends RuntimeException {

    private int code;
    private String msg;

    public APIException() {
        this(ResultCode.FAILED);
    }

    public APIException(ResultCode failed) {
        this.code=failed.getCode();
        this.msg=failed.getMsg();
    }
}

2.全局异常统一处理

package com.suruomo.unified.exception;

import com.suruomo.unified.result.ResultCode;
import com.suruomo.unified.result.ResultVO;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.validation.ObjectError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.util.ArrayList;
import java.util.List;

/**
 * @author suruomo
 * @date 2020/8/7 15:39
 * @description: 全局异常处理类
 */
@RestControllerAdvice
@Slf4j
public class GlobalExceptionHandler {

    /**
     * 自定义异常APIException
     */
    @ExceptionHandler(APIException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ResultVO<Object> APIExceptionHandler(APIException e) {
        log.error("api异常");
        return  new ResultVO<>(ResultCode.FAILED, e.getMsg());
    }

    /**
     * 方法参数错误异常
     * @param e
     * @return
     */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ResultVO<Object> MethodArgumentNotValidExceptionHandler(MethodArgumentNotValidException e) {
        log.error("方法参数错误异常");
        List<String> list=new ArrayList<>();
        // 从异常对象中拿到ObjectError对象
        if (!e.getBindingResult().getAllErrors().isEmpty()){
            for(ObjectError error:e.getBindingResult().getAllErrors()){
                list.add(error.getDefaultMessage().toString());
            }
        }
        // 然后提取错误提示信息进行返回
        return new ResultVO<>(ResultCode.VALIDATE_FAILED, list);
    }
}

4.ResponseControllerAdvice-全局处理增强版Controller

实现ResponseBodyAdvice接口
重写supports和beforeBodyWrite方法
避免Controller里返回数据每次都要用响应体来包装

package com.suruomo.unified.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.suruomo.unified.exception.APIException;
import com.suruomo.unified.result.ResultVO;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

/**
 * @author suruomo
 * @date 2020/8/7 16:38
 * @description: 全局处理增强版Controller，避免Controller里返回数据每次都要用响应体来包装
 */
@RestControllerAdvice(basePackages = {"com.suruomo.unified.controller"}) // 注意哦，这里要加上需要扫描的包
public class ResponseControllerAdvice implements ResponseBodyAdvice<Object> {


    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> aClass) {
        // 如果接口返回的类型本身就是ResultVO那就没有必要进行额外的操作，返回false
        return !returnType.getGenericParameterType().equals(ResultVO.class);
    }


    @Override
    public Object beforeBodyWrite(Object data, MethodParameter returnType, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
        // String类型不能直接包装，所以要进行些特别的处理
        if (returnType.getGenericParameterType().equals(String.class)) {
            ObjectMapper objectMapper = new ObjectMapper();
            try {
                // 将数据包装在ResultVO里后，再转换为json字符串响应给前端
                return objectMapper.writeValueAsString(new ResultVO<>(data));
            } catch (JsonProcessingException e) {
                throw new APIException();
            }
        }
        // 将原本的数据包装在ResultVO里
        return new ResultVO<>(data);
    }
}

注意直接返回String数据不能直接包装，所以需要额外处理

5.TestController

package com.suruomo.unified.controller;

import com.suruomo.unified.pojo.User;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;

/**
 * @author suruomo
 * @date 2020/8/7 15:45
 * @description:
 */
@RestController
public class TestController {

    @GetMapping("/getUser")
    public User getUser() {
        User user = new User();
        user.setId(1L);
        user.setAccount("12345678");
        user.setPassword("12345678");
        user.setEmail("123@qq.com");
        return user;
    }

    @PostMapping("/addUser")
    public void addUser(@Valid @RequestBody User user){
    }
}

6.测试

1.POST测试

使用postman测试

post请求

post请求结果

2.GET测试

get请求

get请求结果