fix: 去除RMIServer中的重复代码段

src/main/java/com/qi4l/JYso/gadgets/utils/JRMPUtils.java

@@ -0,0 +1,25 @@
+package com.qi4l.JYso.gadgets.utils;
+
+import sun.rmi.transport.TransportConstants;
+
+import java.io.BufferedOutputStream;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.Socket;
+
+public class JRMPUtils {
+
+    public static DataOutputStream handshake(DataInputStream in, Socket s) throws IOException {
+        int magic = in.readInt();
+        short version = in.readShort();
+        if (magic != TransportConstants.Magic || version != TransportConstants.Version) {
+            s.close();
+            return null;
+        }
+        OutputStream sockOut = s.getOutputStream();
+        BufferedOutputStream bufOut = new BufferedOutputStream(sockOut);
+        return new DataOutputStream(bufOut);
+    }
+}

src/main/java/com/qi4l/JYso/gadgets/utils/MarshalOutputStream.java

@@ -0,0 +1,43 @@
+package com.qi4l.JYso.gadgets.utils;
+
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+import java.net.URL;
+import java.net.URLClassLoader;
+
+public class MarshalOutputStream extends ObjectOutputStream {
+
+    private final URL sendUrl;
+
+    public MarshalOutputStream(OutputStream out, URL u) throws IOException {
+        super(out);
+        this.sendUrl = u;
+    }
+
+    public MarshalOutputStream(OutputStream out) throws IOException {
+        super(out);
+        this.sendUrl = null;
+    }
+
+    @Override
+    protected void annotateClass(Class<?> cl) throws IOException {
+        if (this.sendUrl != null) {
+            writeObject(this.sendUrl.toString());
+        } else if (!(cl.getClassLoader() instanceof URLClassLoader)) {
+            writeObject(null);
+        } else {
+            URL[] us = ((URLClassLoader) cl.getClassLoader()).getURLs();
+            StringBuilder cb = new StringBuilder();
+            for (URL u : us) {
+                cb.append(u.toString());
+            }
+            writeObject(cb.toString());
+        }
+    }
+
+    @Override
+    protected void annotateProxyClass(Class<?> cl) throws IOException {
+        annotateClass(cl);
+    }
+}