工作之余抽点时间出来写写博文,希望对新接触的朋友有帮助。今天在这里和大家一起学习一下请求对象
Android SDK集成了Apache HttpClient模块。要注意的是,这里的Apache HttpClient模块是HttpClient 4.0(org.apache.http.*),而不是罕见的 Jakarta Commons HttpClient 3.x(org.apache.commons.httpclient.*)。
HttpClient常用HttpGet和HttpPost这两个类,分别对应Get方法和Post方法。
无论是使用HttpGet,还是使用HttpPost,都必须通过如下3步来访问HTTP资源。
1.创立HttpGet或HttpPost对象,将要请求的URL通过构造方法传入HttpGet或HttpPost对象。
2.使用DefaultHttpClient类的execute方法发送HTTP GET或HTTP POST请求,并返回HttpResponse对象。
3.通过HttpResponse接口的getEntity方法返回响应信息,并停止相应的处理。
如果使用HttpPost方法提交HTTP POST请求,则需要使用HttpPost类的setEntity方法设置请求参数。参数则必须用NameValuePair[]数组存储。
上面给出一些实例:
Get方法:
// HttpGet方法请求 public static void requestByHttpGet() throws Exception { String path = "https://reg.163.com/logins.jsp?id=helloworld&pwd=android"; // 新建HttpGet对象 HttpGet httpGet = new HttpGet(path); // 获得HttpClient对象 HttpClient httpClient = new DefaultHttpClient(); // 获得HttpResponse实例 HttpResponse httpResp = httpClient.execute(httpGet); // 判断是够请求成功 if (httpResp.getStatusLine().getStatusCode() == HTTP_200) { // 获得返回的数据 String result = EntityUtils.toString(httpResp.getEntity(), "UTF-8"); Log.i(TAG_HTTPGET, "HttpGet方法请求成功,返回数据如下:"); Log.i(TAG_HTTPGET, result); } else { Log.i(TAG_HTTPGET, "HttpGet方法请求失败"); } }
public String doGet() { String uriAPI = "http://XXXXX?str=I+am+get+String"; String result= ""; // HttpGet httpRequst = new HttpGet(URI uri); // HttpGet httpRequst = new HttpGet(String uri); // 创立HttpGet或HttpPost对象,将要请求的URL通过构造方法传入HttpGet或HttpPost对象。 HttpGet httpRequst = new HttpGet(uriAPI); // new DefaultHttpClient().execute(HttpUriRequst requst); try { //使用DefaultHttpClient类的execute方法发送HTTP GET请求,并返回HttpResponse对象。 HttpResponse httpResponse = new DefaultHttpClient().execute(httpRequst);//其中HttpGet是HttpUriRequst的子类 if(httpResponse.getStatusLine().getStatusCode() == 200) { HttpEntity httpEntity = httpResponse.getEntity(); result = EntityUtils.toString(httpEntity);//取出应答字符串 // 一般来说都要删除过剩的字符 result.replaceAll("\r", "");//去掉返回结果中的"\r"字符,否则会在结果字符串前面显示一个小方格 } else httpRequst.abort(); } catch (ClientProtocolException e) { // TODO Auto-generated catch block e.printStackTrace(); result = e.getMessage().toString(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); result = e.getMessage().toString(); } return result; }
Post方法:
如果使用HttpPost方法提交HTTP POST请求,则需要使用HttpPost类的setEntity方法设置请求参数。参数则必须用NameValuePair[]数组存储。
public String doPost() { String uriAPI = "http://XXXXXX";//Post方法没有参数在这里 String result = ""; HttpPost httpRequst = new HttpPost(uriAPI);//创立HttpPost对象 List <NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("str", "I am Post String")); try { httpRequst.setEntity(new UrlEncodedFormEntity(params,HTTP.UTF_8)); HttpResponse httpResponse = new DefaultHttpClient().execute(httpRequst); if(httpResponse.getStatusLine().getStatusCode() == 200) { HttpEntity httpEntity = httpResponse.getEntity(); result = EntityUtils.toString(httpEntity);//取出应答字符串 } } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); result = e.getMessage().toString(); } catch (ClientProtocolException e) { // TODO Auto-generated catch block e.printStackTrace(); result = e.getMessage().toString(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); result = e.getMessage().toString(); } return result; }
// HttpPost方法请求 public static void requestByHttpPost() throws Exception { String path = "https://reg.163.com/logins.jsp"; // 新建HttpPost对象 HttpPost httpPost = new HttpPost(path); // Post参数 List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("id", "helloworld")); params.add(new BasicNameValuePair("pwd", "android")); // 设置字符集 HttpEntity entity = new UrlEncodedFormEntity(params, HTTP.UTF_8); // 设置参数实体 httpPost.setEntity(entity); // 获得HttpClient对象 HttpClient httpClient = new DefaultHttpClient(); // 获得HttpResponse实例 HttpResponse httpResp = httpClient.execute(httpPost); // 判断是够请求成功 if (httpResp.getStatusLine().getStatusCode() == HTTP_200) { // 获得返回的数据 String result = EntityUtils.toString(httpResp.getEntity(), "UTF-8"); Log.i(TAG_HTTPGET, "HttpPost方法请求成功,返回数据如下:"); Log.i(TAG_HTTPGET, result); } else { Log.i(TAG_HTTPGET, "HttpPost方法请求失败"); } }
文章结束给大家分享下程序员的一些笑话语录: 自从有了Photoshop,我再也不相信照片了!(没有Photoshop的年代,胶片照片年代做假的也不少,那时候都相信假的!)