在android中经常进行网络请求
目前了解的大概有三种
java.net包中的HttpURLConnection类
android的网络请求在4.0后都要求放在子线程中进行
实例
第二种是目前的主流方式
转载自http://blog.csdn.net/u014201191/article/details/49943707
HTTP请求
当然在所有请求中最常用的还是GET与POST两种请求,创建请求的方式如下:
HttpUriRequest request = newHttpPost("http://localhost/index.html");
HttpUriRequest request = newHttpGet(“http://127.0.0.1:8080/index.html”);
HTTP请求格式告诉我们,有两种方式可以为request提供参数:request-line方式与request-body方式。
Ø request-line方式是指在请求行上通过URI直接提供参数。
(1)可以在生成request对象时提供带参数的URI,如:
HttpUriRequest request = newHttpGet("http://localhost/index.html?param1=value1¶m2=value2");
(2)HttpClient程序包还提供了URIUtils工具类,可以通过它生成带参数的URI,如:
URI uri =URIUtils.createURI("http", "localhost", -1,"/index.html",
"param1=value1¶m2=value2", null);
HttpUriRequest request = newHttpGet(uri);
System.out.println(request.getURI());
上例的实例结果如下:
http://localhost/index.html?param1=value1¶m2=value2
(3)需要注意的是,如果参数中含有中文,需将参数进行URLEncoding处理,如:
String param ="param1=" + URLEncoder.encode("中国", "UTF-8") +"¶m2=value2";
URI uri =URIUtils.createURI("http", "localhost", 8080,"/sshsky/index.html",param, null);
System.out.println(uri);
上例的实例结果如下:
http://localhost/index.html?param1=%E4%B8%AD%E5%9B%BD¶m2=value2
(4)对于参数的URLEncoding处理,HttpClient程序包为我们准备了另一个工具类:URLEncodedUtils。通过它,我们可以直观的(但是比较复杂)生成URI,如:
List params = newArrayList(); params.add(newBasicNameValuePair("param1", "中国")); params.add(newBasicNameValuePair("param2", "value2")); String param =URLEncodedUtils.format(params, "UTF-8"); URI uri =URIUtils.createURI("http", "localhost", 8080,"/sshsky/index.html",param, null); System.out.println(uri);
上例的实例结果如下:
http://localhost/index.html?param1=%E4%B8%AD%E5%9B%BD¶m2=value2
Ø request-body方式是指在请求的request-body中提供参数
与 request-line方式不同,request-body方式是在request-body中提供参数,此方式只能用于进行POST请求。在HttpClient程序包中有两个类可以完成此项工作,它们分别是UrlEncodedFormEntity类与MultipartEntity类。这 两个类均实现了HttpEntity接口。
(1)UrlEncodedFormEntity类,故名思意该类主要用于form表单提交。通过该类创建的对象可以模拟传统的HTML表单传送POST请求中的参数。如下面的表单:
[html] view plaincopyprint? <formactionformaction="http://localhost/index.html" method="POST"> <inputtypeinputtype="text" name="param1" value="中国"/> <inputtypeinputtype="text" name="param2" value="value2"/> <inupttypeinupttype="submit" value="submit"/> </form>即可以通过下面的代码实现:
[java] view plaincopyprint? List formParams = newArrayList(); formParams.add(newBasicNameValuePair("param1", "中国")); formParams.add(newBasicNameValuePair("param2", "value2")); HttpEntity entity = newUrlEncodedFormEntity(formParams, "UTF-8"); HttpPost request = newHttpPost(“http://localhost/index.html”); request.setEntity(entity);当然,如果想查看HTTP数据格式,可以通过HttpEntity对象的各种方法取得。如:
[java] view plaincopyprint? List formParams = newArrayList(); formParams.add(newBasicNameValuePair("param1", "中国")); formParams.add(newBasicNameValuePair("param2", "value2")); UrlEncodedFormEntity entity =new UrlEncodedFormEntity(formParams, "UTF-8"); System.out.println(entity.getContentType()); System.out.println(entity.getContentLength()); System.out.println(EntityUtils.getContentCharSet(entity)); System.out.println(EntityUtils.toString(entity));上例的实例结果如下:
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
39
UTF-8
param1=%E4%B8%AD%E5%9B%BD¶m2=value2
(2)除了传统的application/x-www-form-urlencoded表单,还有另一个经常用到的是上传文件用的表单,这种表单的类型为 multipart/form-data。在HttpClient程序扩展包(HttpMime)中专门有一个类与之对应,那就是MultipartEntity类。此类同样实现了HttpEntity接口。如下面的表单:
[html] view plaincopyprint? <formactionformaction="http://localhost/index.html" method="POST" enctype="multipart/form-data"> <inputtypeinputtype="text" name="param1" value="中国"/> <inputtypeinputtype="text" name="param2" value="value2"/> <inputtypeinputtype="file" name="param3"/> <inupttypeinupttype="submit" value="submit"/> </form>可以用下面的代码实现:
[java] view plaincopyprint? MultipartEntity entity = newMultipartEntity(); entity.addPart("param1",new StringBody("中国", Charset.forName("UTF-8"))); entity.addPart("param2",new StringBody("value2", Charset.forName("UTF-8"))); entity.addPart("param3",new FileBody(new File("C:\\1.txt"))); HttpPost request = newHttpPost(“http://localhost/index.html”); request.setEntity(entity);我们可以在上传文件或者模拟表单提交的时候,使用下列更多的方式,同样也满足流的处理
[html] view plain copy print ? /*方法一*/ InputStreamBody inputStreamBody = new InputStreamBody(file, fileName); MultipartEntity entity = new MultipartEntity(); //注意file是在后台中接受的参数File file entity.addPart("file", inputStreamBody); entity.addPart("name", new StringBody("value", Charset.forName("UTF-8"))); httpPost.setEntity(entity); /* 方法二 * 跟方法一不同的就是 inputStreamBody 中可以接受的流参数 */ InputStream in = new FileInputStream(new File("c:\\file.txt")); InputStreamBody inputStreamBody = new InputStreamBody(in, "fileName"); MultipartEntity entity = new MultipartEntity(); entity.addPart("file", inputStreamBody); httpPost.setEntity(entity); /*方法三 * 使用表单FormBodyPart来模拟体检file */ ContentBody contentBody = new FileBody(new File("c:\\file.txt")); FormBodyPart formBodyPart = new FormBodyPart("file", contentBody); formBodyPart.addField("name", "value"); MultipartEntity entity = new MultipartEntity(); entity.addPart(formBodyPart); httpPost.setEntity(entity); /*方法四 * 将流转为二进制,进行传输 */ FileInputStream in = new FileInputStream(new File("")); byte[] b = new byte[1024]; in.read(b); ByteArrayBody byteArrayBody = new ByteArrayBody(b, "android.jpg"); MultipartEntity entity = new MultipartEntity(); entity.addPart("file", byteArrayBody); entity.addPart("name", new StringBody("value", Charset.forName("UTF-8")));实例和步骤:
try { ArrayList<BasicNameValuePair> arrayList = new ArrayList<BasicNameValuePair>(); BasicNameValuePair nameValuePair = new BasicNameValuePair("username",userName); BasicNameValuePair nameValuePair1 = new BasicNameValuePair("pwd",password); arrayList.add(nameValuePair); arrayList.add(nameValuePair1); //使用HttpClient请求服务器将用户密码发送服务器验证 String url = "http://192.168.36.77:8567/itheima74/servlet/LoginServlet"; //1、创建一个httpClient对象 HttpClient client = new DefaultHttpClient(); //2、创建一个请求 HttpPost post = new HttpPost(url); //设置要发送的集合 //创建一个Entity UrlEncodedFormEntity entity = new UrlEncodedFormEntity(arrayList,"utf-8"); //设置请求时的内容 post.setEntity(entity); //3、执行http请求 HttpResponse response = client.execute(post); //4.获取请求的状态码 if(response.getStatusLine().getStatusCode()==200){ HttpEntity responseEntity = response.getEntity(); InputStream in = responseEntity.getContent(); //5.判断状态码后获取内容 //获取实体内容,中封装的有http请求返回的流信息 将流信息转换成字符串 String result = StreamUtils.streamToString(in); Message msg = Message.obtain(); msg.what=2; msg.obj = result; handler.sendMessage(msg); } 第三种方式:开源项目 (asyncHttpClient)这是一个开源项目别人早封装好了,,只有调用就好。
get方式: public static void requestNetForGetLogin(final Context context,final Handler handler ,final String username, final String password) { //使用HttpClient请求服务器将用户密码发送服务器验证 try{ String path = "http://192.168.13.83:8080/alleged/servlet/LoginServlet?username="+URLEncoder.encode(username,"utf-8")+"&pwd="+URLEncoder.encode(password,"utf-8"); //创建一个AsyncHttpClient对象 AsyncHttpClient asyncHttpClient = new AsyncHttpClient(); asyncHttpClient.get(path, new AsyncHttpResponseHandler() { @Override public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) { //statusCode:状态码 headers:头信息 responseBody:返回的内容,返回的实体 //判断状态码 if(statusCode == 200){ //获取结果 try { String result = new String(responseBody,"utf-8"); Toast.makeText(context, result, 0).show(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } @Override public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) { System.out.println("...............onFailure"); } }); }catch (Exception e) { e.printStackTrace(); } } post方式: String path = "http://192.168.13.83:8080/alleged/servlet/LoginServlet"; AsyncHttpClient asyncHttpClient = new AsyncHttpClient(); RequestParams params = new RequestParams(); params.put("username", username); params.put("pwd", password); //url: parmas:请求时携带的参数信息 responseHandler:是一个匿名内部类接受成功过失败 asyncHttpClient.post(path, params, new AsyncHttpResponseHandler() { @Override public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) { //statusCode:状态码 headers:头信息 responseBody:返回的内容,返回的实体 //判断状态码 if(statusCode == 200){ //获取结果 try { String result = new String(responseBody,"utf-8"); Toast.makeText(context, result, 0).show(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } @Override public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) { } });
