fix: 修改sn生成随机规则

@@ -455,18 +455,22 @@ public class TkDeviceServiceImpl extends AbstractBaseService<DeviceMapper, TkDev
 
   @Override
   public String generateSn() {
-    StringBuilder snBuilder = new StringBuilder();
-    for (int i = 0; i < 2; i++) {
-      // 生成uuid的hashCode值
-      int hashCode = UUID.randomUUID().toString().hashCode();
-      // 可能为负数
-      if (hashCode < 0) {
-        hashCode = -hashCode;
+    //随机生成16位字符+数字
+    String val = "";
+    Random random = new Random();
+    for(int i = 0; i < 16; i++) {
+
+      String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
+      //输出字母还是数字
+      if( "char".equalsIgnoreCase(charOrNum) ) {
+        //输出是大写字母还是小写字母
+        int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
+        val += (char)(random.nextInt(26) + temp);
+      } else if( "num".equalsIgnoreCase(charOrNum) ) {
+        val += String.valueOf(random.nextInt(10));
       }
-      snBuilder.append(hashCode);
     }
-
-    return snBuilder.substring(0, 16);
+    return val;
   }
 
   @Override