英文:
Array keeps on adding same value in interceptor
问题
我试图做的是构建一个简单的拦截器，用于检查用户是否在标头中指定了语言属性。我已经进行了所有配置，并且一切都运行良好，但如果我提交请求超过一次，我会看到错误消息再次添加到数组中，现在显示两次。
以下是拦截器的代码：
public class LanguageInterceptor extends HandlerInterceptorAdapter {private List<String> errors = new ArrayList<>();private BadRequestException badRequestException = new BadRequestException();private BadRequestExceptionData badRequestExceptionData = new BadRequestExceptionData();@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {String localeLang = request.getHeader("Accept-Language");if (null == localeLang) {badRequestException.setStatus(HttpStatus.BAD_REQUEST.value());badRequestException.setTitle("Illegal request");errors.add("No language attribute specified in your request!");badRequestExceptionData.setPageSize(errors);badRequestException.setErrors(badRequestExceptionData);ObjectMapper objectMapper = new ObjectMapper();response.setStatus(HttpStatus.BAD_REQUEST.value());response.getWriter().write(objectMapper.writeValueAsString(badRequestException));response.setHeader("Content-Type", "application/json");return false;}return true;}}
示例响应：
{"status": 400,"errors": {"pageSize": ["No language specified in your request!","No language specified in your request!"]},"title": "Illegal request"}
我是否做错了什么，还是在 preHandle 函数完成时必须清空对象？如果我的问题听起来有点迟钝，我向你道歉，我对Java和Spring Boot还不太熟悉。
英文:
What I am trying to do is build a simple interceptor that checks whether the user has specified a language attribute in the headers or not. I have configured everything and all is running well but if I submit the request more than one time, I see that the error message got added in the array again and now is showing twice.
This is the code for the interceptor:
public class LanguageInterceptor extends HandlerInterceptorAdapter {private List errors = new ArrayList();private BadRequestException badRequestException = new BadRequestException();private BadRequestExceptionData badRequestExceptionData = new BadRequestExceptionData();@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {String LocaleLang = request.getHeader("Accept-Language");if(null == LocaleLang) {badRequestException.setStatus(HttpStatus.BAD_REQUEST.value());badRequestException.setTitle("Illegal request");errors.add("No language attribute specified in your request!");badRequestExceptionData.setPageSize(errors);badRequestException.setErrors(badRequestExceptionData);ObjectMapper objectMapper = new ObjectMapper();response.setStatus(HttpStatus.BAD_REQUEST.value());response.getWriter().write(objectMapper.writeValueAsString(badRequestException));response.setHeader("Content-Type", "application/json");return false;}return true;}}
Example response:
{"status": 400,"errors": {"pageSize": ["No language specified in your request!","No language specified in your request!"]},"title": "Illegal request"}
Am I doing something wrong or do I have to empty the object when the preHandle function is done? My apologies if this question sounds a bit dull, I am still new to Java and Spring boot.
答案1
得分: 1
看起来 LanguageInterceptor 已经被实例化为一个单例。将这三个变量都移到 preHandle 方法内部，使它们成为局部变量而不是实例变量。
List errors = new ArrayList();BadRequestException badRequestException = new BadRequestException();BadRequestExceptionData badRequestExceptionData = new BadRequestExceptionData();
英文:
It looks like LanguageInterceptor has been instantiated as a singleton. Shift all these three variables inside the method, preHandle to make them local instead of instance variables.
List errors = new ArrayList();BadRequestException badRequestException = new BadRequestException();BadRequestExceptionData badRequestExceptionData = new BadRequestExceptionData();
答案2
得分: 0
LanguageInterceptor是一个单例bean，errors列表将保持每个请求的状态。
您可以通过在方法内部声明列表来解决此问题。
同样，我建议您对异常也采取相同的做法。
英文:
The LanguageInterceptor is a singleton bean, the errors List will keep the status on every request.
You can solve this issue by declaring the list inside the method.
Also, I recommend you do the same for the exceptions.
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