update doc

Author: colodoo

README.md

@@ -5,6 +5,19 @@
 
 ## 使用方法
 
+### 两种传输URL方式
+```java
+    // 第一种
+    String url = "http://huangty.com";
+    Requests requests = new Requests(url);
+    String response = requests.get().text;
+    // 第二次
+    String url = "http://huangty.com";
+    Requests requests = new Requests();
+    String response = requests.get(url).text;
+
+```
+
 ### 普通请求
 ```java
     String url = "http://huangty.com";
@@ -30,7 +43,15 @@
 ```java
     String url = "http://huangty.com";
     Requests requests = new Requests();
-    requests.addHeader("Content-Type", "application/json;charset=utf-8");
+    List<Map<String, String>> headers = new ArrayList<Map<String, String>>();
+        HashMap<String, String> header = new HashMap<String, String>(){
+        {
+            put("Content-Type", "application/json;charset=utf-8");
+            // ...
+        }
+    };
+    headers.add(header);
+    requestss.headers = headers;
     String response = requests.get(url).text;
     // String response = requests.post(url).text;
     System.out.println(response);