为什么HttpServlet抛出IOException？

Question

I get why an HttpServlet would throw ServletException, but why IOException? What was the reasoning behind this?

Answer 1

From the docs:

IOException - if an input or output error is detected when the servlet handles the GET request

This can happen when you print the servlet output:

response.getWriter().print() - this method throws IOException

The socket can be closed before the response finishes to print the output.

Answer 2

我建议IOException指示处理输入/输出有问题，例如从请求输入读取或写入响应的问题，而ServletException与servlet特定的问题更多有关，例如有关servlet设置/初始化的错误。 ，并处理请求。

Answer 3

If the servlet writes to an output stream (ie the page) through I/O interfaces, any I/O error will be reported as an IOException .

Perhaps the API shouldn't be using I/O interfaces directly. It's not uncommon for WebApps using RMI to allow the RMIException to be fall through the servlet interface (it's a subclass of IOException for some reason).