Merge pull request #480 from uliian/master

xxl-job-admin/src/main/java/com/xxl/job/admin/core/conf/XxlJobAdminConfig.java

 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Configuration;
 
+import javax.annotation.PostConstruct;
+
 /**
  * xxl-job config
  *
         return i18n;
     }
 
+    @PostConstruct
+    public void init() {
+        if(this.getLoginUsername().length()>18){
+            throw new IllegalArgumentException("username length greater than 18");
+        }
+
+        if(this.getLoginPassword().length()>18){
+            throw new IllegalArgumentException("password length greater than 18");
+        }
+    }
 }