java java中的Servlet/过滤器特定异常处理
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Servlet/filter specific exception handling in java
提问by user30622
I have a servlet extending HttpServletand implementing a GETrequest. I also use a filter (from an external library) which is mapped to the above servlet url. Now an exception is thrown by the filter, and as expected I get this
我有一个扩展HttpServlet和实现GET请求的 servlet 。我还使用了映射到上述 servlet url 的过滤器（来自外部库）。现在过滤器抛出了一个异常，正如预期的那样，我得到了这个
SEVERE: Servlet.service() for servlet [myServlet] in context with path [] threw exception
严重：servlet [myServlet] 的 Servlet.service() 在路径 [] 的上下文中引发异常
I know error-pagedescription is probably a standard way to catch this exception, but is there a way to catch the exception from a specific servlet filter ? I already have an error-pagedescription and redirecting to a simple html page. I also don't want to redirect to a jsp page or so, and play around with error parameters. In short, my questions are :
我知道error-page描述可能是捕获此异常的标准方法，但是有没有办法从特定的 servlet 过滤器中捕获异常？我已经有了error-page描述并重定向到一个简单的 html 页面。我也不想重定向到一个jsp页面左右，并玩弄错误参数。简而言之，我的问题是：
- Is there a simpler, elegant way to catch an exception for a specificservlet and handle them ? The
error-pagedescriptor doesn't seem to have any fields to choose the servlet which throws an exception. - Is it possible to catch an exception occuring inside a specificfilter and handle them, given that the exception thrown by the filter is not a custom exception ?
- 有没有更简单、优雅的方法来捕获特定servlet的异常并处理它们？该
error-page描述似乎没有任何字段选择哪抛出异常的servlet。 - 鉴于过滤器抛出的异常不是自定义异常，是否可以捕获特定过滤器内发生的异常并处理它们？
采纳答案by ramp
Can you not extend the Filter and handle the exception thrown by super?
不能扩展Filter，处理super抛出的异常吗？
public class MyFilter extends CustomFilter{
private static final Map<String, String> exceptionMap = new HashMap<>();
public void init(FilterConfig config) throws ServletException {
super.init(config);
exceptionMap.put("/requestURL", "/redirectURL");
exceptionMap.put("/someOtherrequestURL", "/someOtherredirectURL");
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
try{
super.doFilter(request, response, chain);
}catch(Exception e)
//log
String errURL = exceptionMap.get(request.getRequestURI());
if(errURL != null){
response.sendRedirect(errURL);
}
}
}
}
