api: add query pair

Author: YangSen-qn

src/main/java/com/qiniu/storage/Api.java

@@ -662,6 +662,18 @@ protected void addQueryPair(String key, String value) {
             query = null;
         }
 
+        protected void addQueryPair(String key, Integer value) {
+            addQueryPair(key, value+"");
+        }
+
+        protected void addQueryPair(String key, Long value) {
+            addQueryPair(key, value+"");
+        }
+
+        protected void addQueryPair(String key, Boolean value) {
+            addQueryPair(key, value+"");
+        }
+
         /**
          * 获取 query 字符串
          *

src/main/java/com/qiniu/storage/DownloadUrl.java

@@ -164,7 +164,7 @@ public String buildURL() throws QiniuException {
         didSetKeyForUrl(request);
 
         if (!StringUtils.isNullOrEmpty(fop)) {
-            request.addQueryPair(fop, null);
+            request.addQueryPair(fop, (String) null);
         }
 
         for (Api.Request.Pair<String, String> pair : customQuerys) {