feat:修改返回对象R，添加success标识是否成功

src/main/java/com/anyway/util/R.java

@@ -34,6 +34,10 @@ public class R<T> {
      */
     private long ts = System.currentTimeMillis();
 
+    public boolean isSuccess() {
+        return code == 0;
+    }
+
     /**
      * 成功返回
      *