init

src/main/java/com/rosetta/im/protocol/util/StringUtil.java

@@ -0,0 +1,15 @@
+package com.rosetta.im.protocol.util;
+
+public class StringUtil {
+    
+    public static String randomString(int length) {
+        StringBuilder sb = new StringBuilder();
+        String characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+        for (int i = 0; i < length; i++) {
+            int index = (int) (Math.random() * characters.length());
+            sb.append(characters.charAt(index));
+        }
+        return sb.toString();
+    }
+
+}