我可以关闭servlet中的包装输入流或输出流类吗？

Question

I have a code like...

class DemoServlet extends HttpServlet
 {    
  doPost(HttpReqeust httpRequest,HttpResponse httpResponse)
       {
           try {
               ObjectInputStream input=new ObjectInputStream(httpRequest.getInputStream());
               Object ojb=input.readObject();
               ObjectOutputStream output=new ObjectOutputStream(httpResponse.getOutputStream());
               }
           catch(Exception ex){
                  ex.printStackTrace();
              }
           finally{
               input.close();  // it is necessary to close or it will handle by the servlet container to
               output.close(); // the outputstream or inputstream.
           }
      }}

I know that close for httpRequest.getInputStream() and httpResponse.getOutputStream() is not required but is it right to close the Stream class which is wrapping the inputstream and outputstream.Is they create some issue or throw exception.

Answer 1

The wrapper streams/readers/writers in the Java SE close the underlying streams (when they get closed), so if you want to keep them open, do not close the wrappers.

Edit: The Reader 's close() documentation probably explains better. The wrappers (like InputStreamReader ) usually extend this class for the interfaces without overriding the documentation.

In case of ObjectOutputStream the case is similar you can check the behaviour in source .

Answer 2

让我们从Java EE 5教程-过滤请求和响应开始 ，在其中进行了详细说明，并举例说明了如何使用HttpServletResponseWrapper和HttpServletRequestWrapper定制请求和响应。