diff --git a/src/oss_util.rs b/src/oss_util.rs
index 60434bb..9ddb151 100644
--- a/src/oss_util.rs
+++ b/src/oss_util.rs
@@ -85,15 +85,12 @@ impl OSSClient {
         let current_secs = get_current_secs();
         let expire_secs = current_secs + expire_in_seconds;
     
-        signed_url.push_str("?Expires=");
-        signed_url.push_str(&expire_secs.to_string());
-        signed_url.push_str("&OSSAccessKeyId=");
-        signed_url.push_str(&urlencoding::encode(&self.access_key_id));
-        signed_url.push_str("&Signature=");
+        signed_url.push_str(&format!("?Expires={}", &expire_secs.to_string()));
+        signed_url.push_str(&format!("&OSSAccessKeyId={}", &urlencoding::encode(&self.access_key_id)));
     
         let to_be_signed = get_to_be_signed(verb, expire_secs, bucket_name, key);
         let signature = calc_hmac_sha1(self.access_key_secret.as_bytes(), to_be_signed.as_bytes());
-        signed_url.push_str(&urlencoding::encode(&signature));
+        signed_url.push_str(&format!("&Signature={}", &urlencoding::encode(&signature)));
     
         signed_url
     }
@@ -113,24 +110,16 @@ fn remove_endpoint_http_or_s(endpoint: &str) -> String {
 fn get_to_be_signed(verb: &str, expire_secs: u64, bucket_name: &str, key: &str) -> String {
     let mut to_be_signed = String::with_capacity(512);
     to_be_signed.push_str(verb);
-    to_be_signed.push_str("\n");
-    to_be_signed.push_str("\n");
-    to_be_signed.push_str("\n");
+    to_be_signed.push_str("\n\n\n");
     to_be_signed.push_str(&expire_secs.to_string());
     to_be_signed.push_str("\n");
-    to_be_signed.push_str("/");
-    to_be_signed.push_str(bucket_name);
-    to_be_signed.push_str("/");
-    to_be_signed.push_str(key);
+    to_be_signed.push_str(&format!("/{}/{}", bucket_name, key));
     to_be_signed
 }
 
 fn calc_hmac_sha1(key: &[u8], message: &[u8]) -> String {
-    match Hmac::<Sha1>::new_varkey(key) {
-        Ok(mut mac) => {
-            mac.input(message);
-            base64::encode(&mac.result().code())
-        },
-        Err(e) => format!("[ERROR]Hmac error: {}", e),
-    }
+    Hmac::<Sha1>::new_varkey(key).map(|mut mac| {
+        mac.input(message);
+        base64::encode(&mac.result().code())
+    }).unwrap_or_else(|e| format!("[ERROR]Hmac error: {}", e))
 }