其实本没有没打算写这篇的，但还是要写一下写这篇博客的起因是因为，现在呆着的这家公司居然没有统一的API返回格式?，询问主管他居然告诉我用HTTP状态码就够用了（fxxk），天哪HTTP状态码真的够用吗？
在仔细的阅读了项目源码后发现，在API请求的是居然没有业务异常（黑人问好）。好吧居然入坑了只能遵照项目风格了，懒得吐槽了。
因为项目已经开发了半年多了,要是全部接口都做修改工作量还是挺大的,只能用这种无侵入式的方案来解决.
项目源代码:https://github.com/469753862/galaxy-blogs/tree/master/code/responseResult
定义JSON格式
定义返回JSON格式
后端返回给前端一般情况下使用JSON格式,定义如下
{
"code": 200,
"message": "OK",
"data": {
}
}- code:返回状态码
- message:返回信息的描述
- data:返回值
定义JavaBean字段
定义状态码枚举类
@ToString
@Getter
public enum ResultStatus {
SUCCESS(HttpStatus.OK, 200, "OK"),
BAD_REQUEST(HttpStatus.BAD_REQUEST, 400, "Bad Request"),
INTERNAL_SERVER_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, 500, "Internal Server Error"),;
private HttpStatus httpStatus;
private Integer code;
private String message;
ResultStatus(HttpStatus httpStatus, Integer code, String message) {
this.httpStatus = httpStatus;
this.code = code;
this.message = message;
}
}状态码和信息以及http状态码就能一一对应了便于维护,有同学有疑问了为什么要用到http状态码呀,因为我要兼容项目以前的代码,没有其他原因,当然其他同学不喜欢http状态码的可以吧源码中HttpStatus给删除了
定义返回体类
@Getter
@ToString
public class Result<T> {
private Integer code;
private String message;
private T data;
private Result(ResultStatus resultStatus, T data) {
this.code = resultStatus.getCode();
this.message = resultStatus.getMessage();
this.data = data;
}
public static Result<Void> success() {
return new Result<Void>(ResultStatus.SUCCESS, null);
}
public static <T> Result<T> success(T data) {
return new Result<T>(ResultStatus.SUCCESS, data);
}
public static <T> Result<T> success(ResultStatus resultStatus, T data) {
if (resultStatus == null) {
return success(data);
}
return new Result<T>(resultStatus, data);
}
public static <T> Result<T> failure() {
return new Result<T>(ResultStatus.INTERNAL_SERVER_ERROR, null);
}
public static <T> Result<T> failure(ResultStatus resultStatus) {
return failure(resultStatus, null);
}
public static <T> Result<T> failure(ResultStatus resultStatus, T data) {
if (resultStatus == null) {
return new Result<T>(ResultStatus.INTERNAL_SERVER_ERROR, null);
}
return new Result<T>(resultStatus, data);
}
}因为使用构造方法进行创建对象太麻烦了,我们使用静态方法来创建对象这样简单明了
Result实体返回测试
@RestController
@RequestMapping("/hello")
public class HelloController {
private static final HashMap<String, Object> INFO;
static {
INFO = new HashMap<>();
INFO.put("name", "galaxy");
INFO.put("age", "70");
}
@GetMapping("/hello")
public Map<String, Object> hello() {
return INFO;
}
@GetMapping("/result")
@ResponseBody
public Result<Map<String, Object>> helloResult() {
return Result.success(INFO);
}
}到这里我们已经简单的实现了统一JSON格式了,但是我们也发现了一个问题了,想要返回统一的JSON格式需要返回Result<Object>才可以,我明明返回Object可以了,为什么要重复劳动,有没有解决方法,当然是有的啦,下面我们开始优化我们的代码吧
统一返回JSON格式进阶
全局处理(@RestControllerAdvice)
我师傅经常告诉我的一句话:“你就是一个小屁孩,你遇到的问题都已经不知道有多少人遇到过了,你会想到的问题,已经有前辈想到过了.你准备解决的问题,已经有人把坑填了”。是不是很鸡汤,是不是很励志,让我对前辈们充满着崇拜,事实上他对我说的是:“自己去百度”,这五个大字,其实这五个大字已经说明上明的B话了,通过不断的百度和Google发现了很多的解决方案.
我们都知道使用@ResponseBody注解会把返回Object序列化成JSON字符串,就先从这个入手吧,大致就是在序列化前把Object赋值给Result<Object>就可以了,大家可以观摩org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice和org.springframework.web.bind.annotation.ResponseBody
@ResponseBody继承类
我们已经决定从@ResponseBody注解入手了就创建一个注解类继承@ResponseBody,很干净什么都没有哈哈,@ResponseResultBody可以标记在类和方法上这样我们就可以跟自由的进行使用了
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
@Documented
@ResponseBody
public @interface ResponseResultBody {
}ResponseBodyAdvice继承类
@RestControllerAdvice
public class ResponseResultBodyAdvice implements ResponseBodyAdvice<Object> {
private static final Class<? extends Annotation> ANNOTATION_TYPE = ResponseResultBody.class;
@Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
return AnnotatedElementUtils.hasAnnotation(returnType.getContainingClass(), ANNOTATION_TYPE) || returnType.hasMethodAnnotation(ANNOTATION_TYPE);
}
@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
// 防止重复包裹的问题出现
if (body instanceof Result) {
return body;
}
return Result.success(body);
}
}RestControllerAdvice返回测试
@RestController
@RequestMapping("/helloResult")
@ResponseResultBody
public class HelloResultController {
private static final HashMap<String, Object> INFO;
static {
INFO = new HashMap<String, Object>();
INFO.put("name", "galaxy");
INFO.put("age", "70");
}
@GetMapping("hello")
public HashMap<String, Object> hello() {
return INFO;
}
@GetMapping("result")
public Result<Map<String, Object>> helloResult() {
return Result.success(INFO);
}
@GetMapping("helloError")
public HashMap<String, Object> helloError() throws Exception {
throw new Exception("helloError");
}
@GetMapping("helloMyError")
public HashMap<String, Object> helloMyError() throws Exception {
throw new ResultException();
}
}是不是很神奇,直接返回Object就可以统一JSON格式了,就不用每个返回都返回Result<T>对象了,直接让SpringMVC帮助我们进行统一的管理,简直完美
只想看接口哦,helloError和helloMyError是会直接抛出异常的接口,我好像没有对异常返回进行统一的处理哦
统一返回JSON格式进阶
异常处理(@ExceptionHandler))
异常处理,差点把这茬给忘了,这个异常处理就有很多方法了,先看看我师傅的处理方式,我刚拿到这个代码的时候很想吐槽,对异常类的处理这么残暴的吗,直接用PrintWriter直接输出结果,果然是老师傅,我要是有100个异常类,不得要写100个ifelse了.赶紧改改睡吧
@Configuration
public class MyExceptionHandler implements HandlerExceptionResolver {
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response,
Object handler, Exception ex) {
PrintWriter out = getPrintWrite(response);
if (ex instanceof XXXException) {
out.write(JsonUtil.formatJson(ResultEnum.PAY_ERROR.getCode(), ex.getMessage()));
} else {
out.write(JsonUtil.formatJson(ResultEnum.FAIL.getCode(), "服务器异常"));
}
if (null != out) {
out.close();
}
return mav;
}
private PrintWriter getPrintWrite(HttpServletResponse response) {
PrintWriter out = null;
try {
response.setHeader("Content-type", "text/html;charset=UTF-8");
response.setCharacterEncoding("UTF-8");
out = response.getWriter();
} catch (IOException e) {
log.error("PrintWriter is exception", e);
}
return out;
}
}上面的代码看看还是没有问题的,别学过去哦,
异常处理@ResponseStatus(不推荐)
@ResponseStatus用法如下,可用在Controller类和Controller方法上以及Exception类上但是这样的工作量还是挺大的
@RestController
@RequestMapping("/error")
@ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR, reason = "Java的异常")
public class HelloExceptionController {
private static final HashMap<String, Object> INFO;
static {
INFO = new HashMap<String, Object>();
INFO.put("name", "galaxy");
INFO.put("age", "70");
}
@GetMapping()
public HashMap<String, Object> helloError() throws Exception {
throw new Exception("helloError");
}
@GetMapping("helloJavaError")
@ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR, reason = "Java的异常")
public HashMap<String, Object> helloJavaError() throws Exception {
throw new Exception("helloError");
}
@GetMapping("helloMyError")
public HashMap<String, Object> helloMyError() throws Exception {
throw new MyException();
}
}
@ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR, reason = "自己定义的异常")
class MyException extends Exception {
}全局异常处理@ExceptionHandler(推荐)
把ResponseResultBodyAdvice类进行改造一下,代码有点多了
主要参考了org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler#handleException()方法,有空可以看一下
@Slf4j
@RestControllerAdvice
public class ResponseResultBodyAdvice implements ResponseBodyAdvice<Object> {
private static final Class<? extends Annotation> ANNOTATION_TYPE = ResponseResultBody.class;
@Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
return AnnotatedElementUtils.hasAnnotation(returnType.getContainingClass(), ANNOTATION_TYPE) || returnType.hasMethodAnnotation(ANNOTATION_TYPE);
}
@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
if (body instanceof Result) {
return body;
}
return Result.success(body);
}
@ExceptionHandler(Exception.class)
public final ResponseEntity<Result<?>> exceptionHandler(Exception ex, WebRequest request) {
log.error("ExceptionHandler: {}", ex.getMessage());
HttpHeaders headers = new HttpHeaders();
if (ex instanceof ResultException) {
return this.handleResultException((ResultException) ex, headers, request);
}
// TODO: 2019/10/05 galaxy 这里可以自定义其他的异常拦截
return this.handleException(ex, headers, request);
}
protected ResponseEntity<Result<?>> handleResultException(ResultException ex, HttpHeaders headers, WebRequest request) {
Result<?> body = Result.failure(ex.getResultStatus());
HttpStatus status = ex.getResultStatus().getHttpStatus();
return this.handleExceptionInternal(ex, body, headers, status, request);
}
protected ResponseEntity<Result<?>> handleException(Exception ex, HttpHeaders headers, WebRequest request) {
Result<?> body = Result.failure();
HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
return this.handleExceptionInternal(ex, body, headers, status, request);
}
protected ResponseEntity<Result<?>> handleExceptionInternal(
Exception ex, Result<?> body, HttpHeaders headers, HttpStatus status, WebRequest request) {
if (HttpStatus.INTERNAL_SERVER_ERROR.equals(status)) {
request.setAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE, ex, WebRequest.SCOPE_REQUEST);
}
return new ResponseEntity<>(body, headers, status);
}
}到此这篇关于SpringBoot统一返回JSON格式实现方法详解的文章就介绍到这了,更多相关SpringBoot返回JSON格式内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
