IllegalStateException:PWC3990:已为此响应调用了getWriter()

Question

java.lang.IllegalStateException: PWC3990: getWriter() has already been called for this response

如何解决这个错误？我运行一个简单的servlet代码来显示条形图.

Answer 1

你不能打电话都 getOutputStream()与getWriter()上相同的反应.请记住,JSP 隐式使用getWriter().