从Applet中读取Cookie：Access Cookies from a Java Applet

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来源：http://www.rgagnon.com/javadetails/java-0180.html

Access Cookies from a java Applet

This Applet uses the package netscape.javascript.JSObject. To compile such program, you have to include in the CLASSPATH the file java40.jar if you have the Netscape Communicator v4 installed or classes.zip for the Microsoft Internet Explorer. Compile with something like

Applet使用包netscape.javascript.JSObject。因为程序的需要，你首先把jre/lib/pulgin.jar加入到classpath路径中去，编译如下：

javac testcookie.java

NOTE: The netscape.javascript.* package is now included in %JRE_HOME%/lib/jaws.jar file.

注：包netscape.javascript.* package现在已经包含在%JRE_HOME%/lib/jaws.jar 文件中。

[HTML file (testCookie.html)]

网页文件：

<HTML>
<HEAD></HEAD>
<BODY>
<APPLET CODE=TestCookie.class MAYSCRIPT HEIGHT=150 WIDTH=200>
</APPLET>
</BODY>
</HTML>

[Java applet (TestCookie.java)]

Applet文件，TestCookie.java

import netscape.javascript.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class TestCookie extends Applet
implements ActionListener {
TextField tf1, tf2;
Button b1, b2, b3;

public void init() {
    tf1 = new TextField(20);
    tf2 = new TextField(20);

    b1 = new Button("Write Cookie");
    b2 = new Button("Read Cookie");
    b3 = new Button("Delete Coookie");

    setLayout(new FlowLayout());
    add(tf1);
    add(tf2);
    add(b1);
    add(b2);
    add(b3);

    b1.addActionListener(this);
    b2.addActionListener(this);
    b3.addActionListener(this);
    }

public void actionPerformed(ActionEvent ae) {
    if (ae.getSource() == b1) {
       /*
       ** write a cookie
       **    computes the expiration date, good for 1 month
       */
       java.util.Calendar c = java.util.Calendar.getInstance();
       c.add(java.util.Calendar.MONTH, 1);
       String expires = "; expires=" + c.getTime().toString();

       String s1 = tf1.getText() + expires;
       System.out.println(s1);

       JSObject myBrowser = JSObject.getWindow(this);
       JSObject myDocument = (JSObject) myBrowser.getMember("document");

       myDocument.setMember("cookie", s1);
       }

    if (ae.getSource() == b2) {
       /*
       **   read a cookie
       */
       tf2.setText(getCookie());
       }

    if (ae.getSource() == b3) {
       /*
       ** delete a cookie, set the expiration in the past
       */
       java.util.Calendar c = java.util.Calendar.getInstance();
       c.add(java.util.Calendar.MONTH, -1);
       String expires = "; expires=" + c.getTime().toString();

       String s1 = tf1.getText() + expires;
       JSObject myBrowser = JSObject.getWindow(this);
       JSObject myDocument = (JSObject) myBrowser.getMember("document");
       myDocument.setMember("cookie", s1);
       }
    }

    public String getCookie() {
      /*
      ** get all cookies for a document
      */
      try {
        JSObject myBrowser = (JSObject) JSObject.getWindow(this);
        JSObject myDocument = (JSObject) myBrowser.getMember("document");
        String myCookie = (String)myDocument.getMember("cookie");
        if (myCookie.length() > 0)
           return myCookie;
        }
      catch (Exception e){
        e.printStackTrace();
        }
      return "?";
      }

     public String getCookie(String name) {
       /*
       ** get a specific cookie by its name, parse the cookie.
       **    not used in this Applet but can be useful
       */
       String myCookie = getCookie();
       String search = name + "=";
       if (myCookie.length() > 0) {
          int offset = myCookie.indexOf(search);
          if (offset != -1) {
             offset += search.length();
             int end = myCookie.indexOf(";", offset);
             if (end == -1) end = myCookie.length();
             return myCookie.substring(offset,end);
             }
          else
            System.out.println("Did not find cookie: "+name);
          }
        return "";
        }
}