springboot项目用ResponseBodyAdvice统一包装返回体-笔记

￡神魔★判官ぃ 2024-03-16 10:41 31阅读 0赞

## springboot项目用ResponseBodyAdvice统一包装返回体-笔记 ##

在使用springboot开发rest api接口时,往往需要和前端对接定义返回的数据结构，这时使用ResponseBodyAdvice统一包装返回体给前端，可以大大减轻后端的工作量，同时也方便对返回体的数据结构做灵活变更。
    使用ResponseBodyAdvice封装好统一的返回体后，Controller中就可以专心处理业务模型和业务数据了。

--------------------

### 定义1个ResponseBodyAdvice接口的实现类 ###

/**
     * 实现 ResponseBodyAdvice接口，并重写其中的方法，即可对我们的controller进行增强操作
     *
     * 不管Controller中 是否使用ResultVO<T>对返回结果包装，
     * 均可被 ResponseBodyAdvice接口 处理返回数据，以使系统 统一结果，统一异常，统一日志
     */
    // 注意哦，这里要加上需要扫描的包
    @RestControllerAdvice(basePackages = {
        "cn.ath.knowwikibackend.rest"})
    public class SysRestBodyAdvice implements ResponseBodyAdvice<Object> {
        
        /**
         * Whether this component supports the given controller method return type
         * and the selected {@code HttpMessageConverter} type.
         *
         * supports方法要返回为true才会执行beforeBodyWrite方法，
         * 所以如果有些情况不需要进行增强操作可以在supports方法里进行判断
         *
         * @param returnType    the return type
         * @param converterType the selected converter type
         * @return {@code true} if {@link #beforeBodyWrite} should be invoked;
         * {@code false} otherwise
         */
        @Override
        public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        
            // 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);
        }
    
        /**
         * Invoked after an {@code HttpMessageConverter} is selected and just before
         * its write method is invoked.
         *
         * 对返回数据进行真正的操作还是在beforeBodyWrite方法中，
         * 我们可以直接在该方法里包装数据，这样就不需要每个接口都进行数据包装了，省去了很多麻烦
         *
         * @param body                  the body to be written
         * @param returnType            the return type of the controller method
         * @param selectedContentType   the content type selected through content negotiation
         * @param selectedConverterType the converter type selected to write to the response
         * @param request               the current request
         * @param response              the current response
         * @return the body that was passed in or a modified (possibly new) instance
         */
        @SneakyThrows
        @Override
        public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
        
    
            // 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<>(body));
                } catch (JsonProcessingException e) {
        
                    throw new APIException("返回String类型错误");
                }
            }
            // 将原本的数据包装在ResultVO里
            return new ResultVO<>(body);
        }
    }

--------------------

### 用到的ResultVO类 ###

import cn.hutool.core.date.DateTime;
    import lombok.Getter;
    import lombok.NoArgsConstructor;
    import lombok.Setter;
    
    @Getter
    @Setter
    @NoArgsConstructor
    public class ResultVO<T> {
        
        int code;
        String msg;
        T content;
        Long timestamp;
        String traceDateTime;
        public ResultVO(int code,String msg,T content){
        
            this.code = code;
            this.msg = msg;
            this.content = content;
            this.timestamp = System.currentTimeMillis();
            this.traceDateTime = DateTime.now().toString();
        }
    
        public ResultVO(int code,String msg){
        
            this.code = code;
            this.msg = msg;
            this.content = null;
            this.timestamp = System.currentTimeMillis();
            this.traceDateTime = DateTime.now().toString();
    
        }
    
        public ResultVO(ResultCodeEnum resultCode, T content) {
        
            this.code = resultCode.getCode();
            this.msg = resultCode.getMsg();
            this.content = content;
            this.timestamp = System.currentTimeMillis();
            this.traceDateTime = DateTime.now().toString();
    
    
        }
    
        public ResultVO(T content){
        
            this(ResultCodeEnum.SUCCESS, content);
        }
    }

--------------------

### 用到的ResultCodeEnum枚举 ###

import lombok.Getter;
    
    @Getter
    public enum ResultCodeEnum {
        
        SUCCESS(0, "操作成功"),
        VERITY_GEN_ERROR(9801,"验证码生成失败"),
        VERITY_IDENTITY_ERROR(9803,"验证码验证失败"),
        TOKEN_NULL(9777, "请求头里没有token"),
        TOKEN_TIME_OUT(9776, "token已过期,请重新登录"),
        TOKEN_USER_ALREADY_SIGN(9775, "token用户已登录,请退出重登后再请求本接口"),
        FAILED(9500, "响应失败"),
        BUSY(9600, "系统繁忙"),
        ACCOUNT_PASS_FAILED(9301, "密码错误"),
        ACCOUNT_NOT_EXIST(9302, "用户名不存在"),
        ACCOUNT_DISABLED(9303, "用户没有权限/已禁用"),
        NOT_LOGIN(9403,"未登录"),
        REQ_BODY_IS_NULL(9995,"requestBody请求体异常"),
        VALIDATE_FAILED(9996, "参数校验异常"),
        ARITHMETIC_FAILED(9997, "算术异常"),
        ARRAY_INDEX_OUT_OF_BOUNDS_FAILED(9998, "数组越界异常"),
        USER_IS_USING(7701,"目标用户正在使用中"),
        IllEGAL_ARG_EXCEPTION(9988,"非法参数异常"),
        ERROR(9999, "未知错误");
    
        private int code;
        private String msg;
    
        ResultCodeEnum(int code, String msg) {
        
            this.code = code;
            this.msg = msg;
        }
    
    }

--------------------

### 在Controller里写rest api接口，不需要手动封装ResultVO,直接返回业务对象即可 ###

@Slf4j
    @RestController
    public class Test0529Api{
        
        @PostMapping("/t123")
        public UserReq test123(@Valid @RequestBody UserReq req){
        
            log.info("req:{}",req.toString());
            return req;
        }
        
        @PostMapping("/alterUser")
        public UserTestResp  alterUser(@RequestBody  @Validated({
        UpdateActionGroup.class})
                                                   UserTestReq1 req ){
        
            log.info("req:{}",req);
            return UserTestResp.builder()
                    .id(req.getId())
                    .age(req.getAge())
                    .name(req.getName())
                    .build();
        }
    }

返回的json数据如下

{
        
        "code": 0,
        "msg": "操作成功",
        "content": [
            {
        
                "account": "wr23r",
                "email": "wr22r12we@163.com",
                "phone": "13531323021",
                "startDt": "2022-05-06 13:14:15",
                "endDt": "2023-06-06 13:30:00",
                "company": {
        
                    "id": 3,
                    "name": "er23r",
                    "tel": "02131470060"
                },
                "testCount": 32
            }
        ],
        "timestamp": 1685352446296,
        "traceDateTime": "2023-05-29 17:27:26"
    }