feat: add isError and isSuccess method

Signed-off-by: runphp <runphp@qq.com>

ruoyi-common/ruoyi-common-core/src/main/java/com/ruoyi/common/core/domain/R.java

@@ -102,4 +102,12 @@ public class R<T> implements Serializable
     {
         this.data = data;
     }
+
+    public Boolean isError() {
+        return !isSuccess();
+    }
+    
+    public Boolean isSuccess() {
+        return R.SUCCESS == getCode();
+    }
 }