Applet 和 JSP 通信 [英] Applet and JSP Communication
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问题描述
我想获取在客户端加载小程序后动态分配的变量的值.Applet 嵌入在 JSP 页面中.在那个 JSP 页面中，我想获得那个值.源代码如下:
I want to get the value of a variable which is dynamically assigned after the applet load in client side. Applet is embedded in a JSP page. Within that JSP page I want to get that value. Source code is given below:
public class CheckJavaVersion extends Applet
{
private static Label versionCheck;
public static String javaVersion;
public void init()
{
try
{
Color colFrameBackground = new Color(198, 0, 0);
this.setBackground(colFrameBackground);
versionCheck = new Label("Java Version:"+System.getProperty("java.version"));
this.add(versionCheck);
javaVersion = versionCheck.getText();
}
}
JSP 页面:
<html>
<head><title>Display Java Version</title>
</head>
<body>
<jsp:plugin code="com.applets.CheckJavaVersion" codebase="/AppletURLComm" type="applet">
</jsp:plugin>
</body>
</html>
现在我想访问 JSP 页面中的 javaversion 变量.如果我访问该变量，它会给出 null 值.如何获取带值的变量?
Now I want to access the javaversion variable in the JSP page. If I access that variable, it is giving null value. How to get the variable with value?
推荐答案
*package thumb;
/**
* @author Ravi Thapa
* @since May 20, 2014
* @version 1.0 This class will get thumb impression image and verification
* String
*/
public class ThumbVerification extends JApplet
implements ActionListener {
base64Image = null;
base64FMR = null;
/*
here is code for thumb image capture code
*/
public static byte[] decodeImage(String imageDataString) {
return Base64.decodeBase64(imageDataString.getBytes());
}
public String getBase64FMR() {
return base64FMR;
}
public String getBase64Image() {
return base64Image;
}
}
我编译代码并转换成jar文件并签名
I compiled the code and convert into jar file and signed
D:\Thumb\build\classes\thumb>keytool -genkey -keystore myKeystore -alias myself
Enter keystore password:
Re-enter new password:
What is your first and last name?
[Unknown]: Ravi
What is the name of your organizational unit?
[Unknown]: abc
What is the name of your organization?
[Unknown]: abc
What is the name of your City or Locality?
[Unknown]: Lucknow
What is the name of your State or Province?
[Unknown]: UP
What is the two-letter country code for this unit?
[Unknown]: 91
Is CN=Ravi Thapa, OU=NIC, O=NIC, L=Lucknow, ST=UP, C=91 correct?
[no]: yes
Enter key password for <myself>
(RETURN if same as keystore password):
Re-enter new password:
D:\SECUGEN_DRIVERS\Thumb\build\classes\thumb>keytool -selfcert -alias myself -kystore myKeystore
Illegal option: -kystore
keytool -selfcert [OPTION]...
Generates a self-signed certificate
Options:
-alias <alias> alias name of the entry to process
-sigalg <sigalg> signature algorithm name
-dname <dname> distinguished name
-startdate <startdate> certificate validity start date/time
-validity <valDays> validity number of days
-keypass <arg> key password
-storetype <storetype> keystore type
-keystore <keystore> keystore name
-storepass <arg> keystore password
-providername <providername> provider name
-providerclass <providerclass> provider class name
-providerarg <arg> provider argument
-providerpath <pathlist> provider classpath
-v verbose output
Use "keytool -help" for all available commands
D:\SECUGEN_DRIVERS\Thumb\build\classes\thumb>keytool -list -keystore myKeystore
Enter keystore password:
Keystore type: JKS
Keystore provider: SUN
Your keystore contains 1 entry
myself, Apr 15, 2014, PrivateKeyEntry,
Certificate fingerprint (SHA1): 24:9C:50:D7:49:47:27:EB:87:9A:BA:89:F4:19:72:6A:02:AF:1B:3F
D:\SECUGEN_DRIVERS\Thumb\build\classes\thumb>jarsigner -keystore myKeystore Thumb.jar myself
Enter Passphrase for keystore:
jar signed.
Warning:
The signer certificate will expire within six months.
No -tsa or -tsacert is provided and this jar is not timestamped. Without a timestamp, users may not be able to validate this jar after the signer certificate's expiration date (2014-07-14) or after any future revocation date.
将jar文件放入jsp文件
Put the jar file into jsp file
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ page import="java.io.File"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></meta>
<meta http-equiv="cache-control" content="no-cache"/>
<script type="text/javascript">
function getVarData(){
var thumbImp = document.Applet1.getBase64FMR();
var thumbImpImage = document.Applet1.getBase64Image();
document.getElementById('varThumb').value = thumbImp;
document.getElementById('varThumbImage').value = thumbImpImage;
}
</script>
</head>
<body>
<table>
<tr>
<td>
<applet code="thumb.ThumbVerification" width="120" height="170" id="Applet1" name="AppletABC"
archive="<%=request.getContextPath()%>/Thumb.jar"></applet>
</td>
</tr>
</table>
</body>
</html>
SEND THE DATA USING HIDDEN FIELD
<input type="submit" value=" SAVE " onclick="getVarData();"/>
<input type="hidden" id="varThumb" name="varThumb"/>
<input type="hidden" id="varThumbImage" name="varThumbImage"/>*
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