如何在Java中使用JProgressBar创建浏览器？

Question

I'm trying to build a browser in Java. It contains JProgressBar, JTextField and JEditorPane, but when I ran the program I found a problem: When the editor pane set the page searched, the JProgressBar doesn't work.

I've tried this code:

  String az = jTextField1.getText();


       if(az.contains("1")){
            String hh = WorkSpace.jTextField1.getText();


    try {
         WorkSpace.jEditorPane1.setPage("" + hh );
         WorkSpace.jProgressBar1.setValue(); // which value?

    } catch (Exception e) {

    }

So should the editor pane set the page when the JProgressBar is complete?

How I can do this?

Answer 1

I think to reach your desired behavior you need to do a little bit more than just set a url to your editor pane and have a browser with progress bars etc.. Coding a brwoser is a painful and complicate work and JEditorPane only covers a little of all possibilities.

However, to cover your needs I think you need to get the content of the page you try to display by your own (using Sockets or httpclient or any other lib). While you receive the bytes from the server you can update the progressbar. After you've received all the bytes you set the content in one step to the pane which should display the content.

Edit: Using Sockets you need to do the following (note that this is quick and dirty an without any kind of error handling):

// Suppose you want to display http://www.target.com/page
Socket s = new Socket("target.com", 80);
PrintWriter out = new PrintWriter(s.getOutputStream());
// Tell the server you want to get "/page"
out.println("GET /page HTTP/1.1");
out.println("Host: target.com");
out.println();

// The target-Server now send you the content of "/page"
// Now you need to know a little about the HTTP-Protocol.
// In short: The server sends you a header and a body. 
// The header and the body is separated using two newlines.
// You need to read line by line from the server until the 
// body starts and interpret the stuff from the header because it
// contains the information how many bytes you will receive with the body
// ( -> Content-Length: xyz)
BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));

// Read the Header and interpret that stuff.
doReadHeader(in);

// Now, because of the Content-Length Header you know how many bytes you need to read
// from the InputStream until all the bytes are receive. Thus you can update your
// progressbar while receiving the bytes
doReadBody(in);

That pretty much is it. After you received all that, you can set the body 1:1 into your EditorPane. But beware the EditorPane just covers little of HTML and CSS. So maybe you need to go with another HTML-Pane like FlyingSaucer or CSSBox...