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Setting both error message and body from servlet

Answer 1

+2 A:

You can customize error pages by specifying error specific pages in web.xml:

<error-page>
  <error-code>500</error-code>
  <location>/error500.jsp</location>
</error-page>

In the jsp file you can use request attributes to show a custom message and other info.

FRotthowe 2010-10-07 20:51:02

Thanks, that is an excellent point and would probably help most people with this problem :) I happen to be using embedded jetty without the whole web app setup: this is a completely stand-alone servlet. I can at least poke around to see if the error page can somehow be setup in code, but I'll probably settle on having programmatic callers just look in the body for the details.

Jeremy Huiskamp 2010-10-07 21:13:27

Answer 2

A:

There's also a setStatus(int) method that you can call with any code, and then you can write your own html body. This is close, except that you can't specify the http response message.

Is there any reason why you would not use response.setStatus(500) to set the HTTP status code, followed by writing to the response's output stream?

This is how "writing to the response body" is achieved at the lowest level.

Here's an example:

public class ErrorServlet extends HttpServlet {

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException {

        // 500 error
        resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        resp.getWriter().print("<html><head><title>Oops an error happened!</title></head>");
        resp.getWriter().print("<body>Something bad happened uh-oh!</body>");
        resp.getWriter().println("</html>");
    }
}

web.xml:

<web-app>
    <servlet>
        <servlet-name>myerror</servlet-name>
        <servlet-class>brown.testservlet.ErrorServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>myerror</servlet-name>
        <url-pattern>/myErrorPage</url-pattern>
    </servlet-mapping>
</web-app>

And the output:

$ curl -I http://localhost:8080/testservlet/myErrorPage  
HTTP/1.1 500 Internal Server Error  
Content-Length: 108  
Server: Jetty(6.1.16)  

$ curl -v http://localhost:8080/testservlet/myErrorPage
* About to connect() to localhost port 8080 (#0)
*   Trying 127.0.0.1... connected
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /testservlet/myErrorPage HTTP/1.1
> User-Agent: curl/7.20.0 (i686-pc-mingw32) libcurl/7.20.0 OpenSSL/0.9.8k zlib/1.2.3
> Host: localhost:8080
> Accept: */*
>
< HTTP/1.1 500 Internal Server Error
< Content-Length: 108
< Server: Jetty(6.1.16)
<
<html><head><title>Oops an error happened!</title></head><body>Something bad happened uh-oh!</body></html>
* Connection #0 to host localhost left intact
* Closing connection #0

matt b 2010-10-08 01:52:24

Yes, the part of my question that you quoted states that I understand this option. It also points out that this does not allow you to set the http response message (the "Internal Server Error" in your example, which is automatically supplied by the servlet container).

Jeremy Huiskamp 2010-10-08 21:02:07

Even though `response.setStatus(int, String)` is deprecated, you *should* be able to use it to set the status line message

matt b 2010-10-09 15:09:31

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Setting both error message and body from servlet

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