Thrown when an image verification code is generated: Java. Lang. illegalstateexception

During the image verification code last night, the verification code was successfully generated, but an exception was thrown: Java. Lang. illegalstateexception: getoutputstream () has already been call for this response Haha, the error status must be when the output stream is closed and the statements are still output to the page. After reading the verification code generatedCode, Indeed:

Outputstream OS = response. getoutputstream ();

...

OS. Flush ();
OS. Close ();

But how can this problem be solved? If the output stream is not cleared, the verification code image will not be generated. No way, you have to turnGoogleFinally, the solution is found: Add the following two statements before the end of the method body:

Out. Clear ();
Out = pagecontext. pushbody ();