如何在Java中使用策略权限运行小程序以读取MAC地址

问题描述：

我正在尝试在NetBeans中开发一个可以读取MAC地址的小程序.

I'm trying to develop an applet in NetBeans which can read the MAC address.

这是我的目录结构

这是我的更新代码

MacAddrApplet.java

import java.awt.Graphics;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Enumeration;
import javax.swing.JApplet;

/**
 *
 * @author jay.patel
 */
public class MacAddressApplet extends JApplet {

    public static String getMacFromInterface(NetworkInterface ni) throws SocketException {
        byte mac[] = ni.getHardwareAddress();

        if (mac != null) {
            StringBuilder macAddress = new StringBuilder("");
            String sep = "";
            for (byte o : mac) {
                macAddress.append(sep).append(String.format("%02X", o));
                sep = ":";
            }
            return macAddress.toString();
        }

        return "";
    }

    public static String[] getInterfaces() {
        try {
            Enumeration<NetworkInterface> nis = NetworkInterface.getNetworkInterfaces();

            ArrayList<String> result = new ArrayList<String>();
            while (nis.hasMoreElements()) {
                NetworkInterface ni = nis.nextElement();
                if (ni.isUp() && !ni.isLoopback() && !ni.isVirtual()) {
                    String mac = getMacFromInterface(ni);
                    String str = ni.getDisplayName() + ";" + mac;
                    result.add(str);
                }
            }
            return result.toArray(new String[0]);
        } catch (SocketException e) {
            System.out.println("SocketException:: " + e.getMessage());
        } catch (Exception e) {
            System.out.println("Exception:: " + e.getMessage());
        }

        return new String[0];
    }

    public static String getInterfacesJSON() {
        try {
            String macs[] = getInterfaces();

            String sep = "";
            StringBuilder macArray = new StringBuilder("['");
            for (String mac : macs) {
                macArray.append(sep).append(mac);
                sep = "','";
            }
            macArray.append("']");

            return macArray.toString();
        } catch (Exception e) {
            System.out.println("Exception:: " + e.getMessage());
        }

        return "[]";
    }

    @Override
    public void paint(Graphics g) {
        super.paint(g);
         AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                String macs[] = getInterfaces();

                for (String mac : macs) {
                    System.out.println(" Interfaces = " + mac);
                }

                System.out.println(" Interfaces JSON = " + getInterfacesJSON());
                g.drawString("MAC: " + getInterfacesJSON(), 100, 100);
                return null;
            }
        });

    }

}

MacAddrApplet.html

<HTML>
<HEAD>
    <TITLE>Applet HTML Page</TITLE>
</HEAD>
<BODY>

    <H3><HR WIDTH="100%">Applet HTML Page<HR WIDTH="100%"></H3>

    <P><APPLET codebase="classes" code="MacAddrApplet.class" width=350 height=200></APPLET></P>

    <HR WIDTH="100%"><FONT SIZE=-1><I>Generated by NetBeans IDE</I></FONT>
</BODY>

applet.policy

grant {
permission java.security.AllPermission;
};

当我尝试从Run -> Run File运行我的applet时，它运行正常，并在其中显示了我的Mac地址，并显示了我正在打印的日志

When I try to run my applet from Run -> Run File it works perfectly fine and shows my Mac address in it, with this log that I'm printing

Interfaces = en1;XX:XX:XX:XX:XX:XX
Interfaces JSON = ['en1;XX:XX:XX:XX:XX:XX']

但是当我尝试使用

appletviewer build/MacAddrApplet.html

它打印

Interfaces = en1;
Interfaces JSON = ['en1;']

我该如何解决这个问题?

P.S.我认为是因为它没有使用applet.policy

P.S. I think it's happening because it's not using the permissions of applet.policy

答

最终，我发现了终端命令出了什么问题

Eventually I figured out what's wrong with the terminal command

appletviewer build/MacAddrApplet.html

因为您看到位于nbproject文件夹中的project.properties文件，所以在结尾部分，您会看到

because if you see the project.properties file located in nbproject folder, at the end part, you'll see

run.jvmargs=-Djava.security.policy=applet.policy

因此，当我使用Run -> Run File运行applet时，Netbeans内部会处理所有事情，因此applet运行得很好.

So when I run the applet using Run -> Run File Netbeans internally took care of everything and hence the applet is running perfectly fine.

但是，在终端的情况下，我需要显式指定policy file(这是我问问题时要知道的内容！)，因此使用此命令运行applet它将正常工作...

But, in case of the terminal, I need to specify the policy file explicitly (This is what I want to know when I asked the question!), So run the applet with this command and it will work fine...

appletviewer -J-Djava.security.policy=applet.policy build/MacAddrApplet.html

如何在Java中使用策略权限运行小程序以读取MAC地址

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