在Java中执行JSP

Question

I am trying to execute a JSP on my local machine by making a URL connection but i can't seem to get it to execute, i thought it could be the java not finding the JSP but i can't seem to find out why this could be as the URL to the JSP looks fine, anybody have an idea why it isn't executing? My code fragment and webapp structure is below.

Thanks.

       URL url = new URL("http://127.0.0.1/folder1/folder2/folder3/test.jsp");
       URLConnection connection = url.openConnection();
       connection.setDoOutput(true);
       OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());
       out.write("id=" + id);
       out.close();

       BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
       String output;
       StringBuilder sb = new StringBuilder();
       boolean started = false;

       while ((output = in.readLine()) != null) {
           if (!output.trim().equals("")) {
                started = true;
           }
            if (started) {
                sb.append(output);
                sb.append("\r\n");
            }
        }
        in.close();
        System.out.println(sb.toString());

My Webapp has a similar structure to the following.

 webapp
    /WEB-INF
         /classes
         web.xml
    /folder1
       /folder2
          /folder3
             test.jsp

Answer 1

I think you might intend to do the following (without the outputting part):

URL url = new URL("http://127.0.0.1/folder1/folder2/folder3/test.jsp?id=" + id);

Use a StringBuilder for output - it is much more efficient.

---

Should text.jsp do both: ask in a form for id , and handle the form, then do not use:

if (request.getMethod().equals("POST")) {
    String id = request.getParameter("id");
    ... handle given id
    return;
}
... show form

but use the GET/POST agnostic/irrelevant code:

String id = request.getParameter("id");
if (id != null) {
    ... handle given id
    return;
}
... show form

So that the HTTP GET you are doing works.

Answer 2

I think you are missing your application name. If you are running your app inside tomcat then default port is 8080.

http://127.0.0.1:<port>/<web-app-name>/folder1/folder2/folder3/test.jsp

Answer 3

I give a troubleshooting approach below, given I don't know much about what failure message you are receiving.

1. I would try accessing another web page other than the URL you provided; just to prove your URLConnection approach is correct and that it is an issue with access to the JSP file.

2. Look into the actual message/page being returned by your request. Is it a 404 page? If so then your URL is off.

3. And ensure you can access that URL directly in your browser.

Answer 4

原来是由于从**http**://localhost/folder1/folder2/folder3/test.jsp重定向到**https**://localhost/folder1/folder2/folder3/test.jsp而导致的问题，当我在浏览器中打开JSP时，这并不是最容易发现的重定向，非常令人讨厌的是url.openConnection（）似乎没有任何反应。