java - 通过 Java 套接字发送带有 <APPLET> 标记的 html 文件

Question

我有一个简单的 java helloworld applet 和一个带有引用该 applet 的标记的 html 文件。当我使用 apache 服务器时，一切正常。客户端电脑访问我服务器的80端口，输入带有applet标签的html，打开applet。

但是，如果我尝试通过某个其他端口通过 Java 套接字发送相同的 html 文件，以便客户端从其浏览器打开它，它不起作用，我会在客户端浏览器上收到小程序错误。

这是我在接受套接字连接时发送文件的方式:

DataOutputStream out=null;
    File f=new File("C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\index.html");
    DataInputStream htmlFile;
    try {
        out = new DataOutputStream(clientSocket.getOutputStream());
        htmlFile = new DataInputStream(new FileInputStream(f));
        int len = (int) f.length();
        byte[] buf = new byte[len];
        htmlFile.readFully(buf);
        htmlFile.close();
        out.writeBytes("HTTP/1.1 200 OK\r\n");
        out.writeBytes("Content-Length: " + f.length() +"\r\n");
        out.writeBytes("Content-Type: text/html\r\n\r\n");
        out.write(buf);
    } catch (FileNotFoundException e2) {
        // TODO Auto-generated catch block
        e2.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

这是我得到的错误:

    Java Plug-in 1.6.0_30
Using JRE version 1.6.0_30-b12 Java HotSpot(TM) Client VM
User home directory = C:\Documents and Settings\Administrator
----------------------------------------------------
c:   clear console window
f:   finalize objects on finalization queue
g:   garbage collect
h:   display this help message
l:   dump classloader list
m:   print memory usage
o:   trigger logging
q:   hide console
r:   reload policy configuration
s:   dump system and deployment properties
t:   dump thread list
v:   dump thread stack
x:   clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------


java.net.MalformedURLException: unknown protocol: c
    at java.net.URL.<init>(Unknown Source)
    at java.net.URL.<init>(Unknown Source)
    at sun.plugin.util.GrayBoxPainter.setProgressFilter(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager.setupGrayBoxPainter(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager.access$700(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
exception: name.
java.lang.IllegalArgumentException: name
    at sun.plugin2.applet.Applet2ClassLoader.addJar(Unknown Source)
    at sun.plugin2.applet.Applet2Manager.loadJarFiles(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Exception: java.lang.IllegalArgumentException: name
java.net.MalformedURLException: unknown protocol: c
    at java.net.URL.<init>(Unknown Source)
    at java.net.URL.<init>(Unknown Source)
    at sun.plugin.util.GrayBoxPainter.setProgressFilter(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager.setupGrayBoxPainter(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager.access$700(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
exception: name.
java.lang.IllegalArgumentException: name
    at sun.plugin2.applet.Applet2ClassLoader.addJar(Unknown Source)
    at sun.plugin2.applet.Applet2Manager.loadJarFiles(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Exception: java.lang.IllegalArgumentException: name
java.lang.ClassFormatError: Incompatible magic value 1013018736 in class file MyApplet/HelloWorld
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(Unknown Source)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Exception: java.lang.ClassFormatError: Incompatible magic value 1013018736 in class file MyApplet/HelloWorld

如果有人能告诉我这是怎么回事或其他方法，我将不胜感激。

编辑:

1. html 源代码(只是 aapplet 标签):

   小程序代码=“MyApplet.HelloWorld”archive=“HelloWorldApplet.jar”,width=300,height=300/

2. 客户端应该输入服务器 ip 地址，后跟“:portNo”。进入浏览器。 “192.168.1.100:4444”

3. 是的，我知道了。这不是applet 标签的用途吗。我的 jar 文件被标记在 html 文件中。如果用户打开 html，则应下载 jar 文件并在客户端浏览器中显示。这不是它的工作原理吗？

4. 我正在 android 上尝试一些东西。我希望能够打开我的 android 在同一 wifi 网络上的计算机上发送的小程序。这看起来像这样做的方法。如果可能的话，在 android 上安装一些网络服务器似乎是一个不必要的复杂化。

Answer 1

它可能与谁有关。

设法解决这个问题。感谢 Nizet 为我指明了正确的方向，直到现在才真正费心去了解 http 是如何工作的。所以最后的重点是模拟 http 如何处理 java 小程序。通过查看加载普通小程序时的请求和响应，我发现在浏览器加载 html 文件后，它会发送对引用的 jar 文件的请求 (GET/HelloWorldApplet.jar HTTP/1.1 ) 然后我必须在这样的 http 响应中返回:

 HTTP/1.1 200 OK
 Content-Length: fileLength
 Content-Type: application/java-archive

 Then send jar file as byte buffer.

全类同学:

public class MyThread extends Thread{
    Socket clientSocket;
    public MyThread(Socket socket){
        this.clientSocket=socket;
    }
    public void run(){

        System.out.println("Connection established!");

        DataOutputStream out=null;
        File h=new File("index.html");
        File j=new File("HelloWorldApplet.jar");
        DataInputStream htmlFile;
        DataInputStream jarFile;
        BufferedReader br=null;
        try {
            br=new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            out = new DataOutputStream(clientSocket.getOutputStream());
            htmlFile = new DataInputStream(new FileInputStream(h));
            jarFile=new DataInputStream(new FileInputStream(j));
            int hlen = (int) h.length();
            int jlen=(int) j.length();
            byte[] hbuf = new byte[hlen];
            byte[] jbuf = new byte[jlen];
            htmlFile.readFully(hbuf);
            jarFile.readFully(jbuf);
            htmlFile.close();
            jarFile.close();
            String request=br.readLine();
            System.out.println(request);
            if(request.startsWith("GET / HTTP/1.1")){
                out.writeBytes("HTTP/1.1 200 OK\r\n");
                out.writeBytes("Content-Length: " + h.length() + "\r\n");
                out.writeBytes("Content-Type: text/html\r\n\r\n");
                out.write(hbuf);
            }
            if(request.startsWith("GET /HelloWorldApplet.jar HTTP/1.1")){
                out.writeBytes("HTTP/1.1 200 OK\r\n");
                out.writeBytes("Content-Length: " + j.length() + "\r\n");
                out.writeBytes("Content-Type: application/java-archive\r\n\r\n");
                out.write(jbuf);
            }
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch(NullPointerException e){
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        try {
            out.close();
            clientSocket.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}