Android网络连接之HttpURLConnection和HttpClient

1.概念  

HTTP 协议可能是现在 Internet 上使用得最多、最重要的协议了，越来越多的 Java 应用程序需要直接通过 HTTP 协议来访问网络资源。在 JDK 的 java.net 包中已经提供了访问 HTTP 协议的基本功能：HttpURLConnection。但是对于大部分应用程序来说，JDK 库本身提供的功能还不够丰富和灵活。

除此之外，在Android中，androidSDK中集成了Apache的HttpClient模块，用来提供高效的、最新的、功能丰富的支持 HTTP 协议工具包，并且它支持 HTTP 协议最新的版本和建议。使用HttpClient可以快速开发出功能强大的Http程序。

2.区别

HttpClient是个很不错的开源框架，封装了访问http的请求头，参数，内容体，响应等等，

HttpURLConnection是java的标准类，什么都没封装，用起来太原始，不方便，比如重访问的自定义，以及一些高级功能等。

3.案例

URLConnection

    String urlAddress = "http://192.168.1.102:8080/AndroidServer/login.do";      URL url;      HttpURLConnection uRLConnection;      public UrlConnectionToServer(){  

    }  

    //向服务器发送get请求    public String doGet(String username,String password){          String getUrl = urlAddress + "?username="+username+"&password="+password;          try {              url = new URL(getUrl);              uRLConnection = (HttpURLConnection)url.openConnection();              InputStream is = uRLConnection.getInputStream();              BufferedReader br = new BufferedReader(new InputStreamReader(is));              String response = "";              String readLine = null;              while((readLine =br.readLine()) != null){                  //response = br.readLine();                  response = response + readLine;              }              is.close();              br.close();              uRLConnection.disconnect();              return response;          } catch (MalformedURLException e) {              e.printStackTrace();              return null;          } catch (IOException e) {              e.printStackTrace();              return null;          }      }        

    //向服务器发送post请求    public String doPost(String username,String password){          try {              url = new URL(urlAddress);              uRLConnection = (HttpURLConnection)url.openConnection();              uRLConnection.setDoInput(true);              uRLConnection.setDoOutput(true);              uRLConnection.setRequestMethod("POST");              uRLConnection.setUseCaches(false);              uRLConnection.setInstanceFollowRedirects(false);              uRLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");              uRLConnection.connect();  

            DataOutputStream out = new DataOutputStream(uRLConnection.getOutputStream());              String content = "username="+username+"&password="+password;              out.writeBytes(content);              out.flush();              out.close();  

            InputStream is = uRLConnection.getInputStream();              BufferedReader br = new BufferedReader(new InputStreamReader(is));              String response = "";              String readLine = null;              while((readLine =br.readLine()) != null){                  //response = br.readLine();                  response = response + readLine;              }              is.close();              br.close();              uRLConnection.disconnect();              return response;          } catch (MalformedURLException e) {              e.printStackTrace();              return null;          } catch (IOException e) {              e.printStackTrace();              return null;          }      }  

HTTPClient

String urlAddress = "http://192.168.1.102:8080/qualityserver/login.do";  public HttpClientServer(){  

 }  

public String doGet(String username,String password){      String getUrl = urlAddress + "?username="+username+"&password="+password;      HttpGet httpGet = new HttpGet(getUrl);      HttpParams hp = httpGet.getParams();      hp.getParameter("true");      //hp.      //httpGet.setp      HttpClient hc = new DefaultHttpClient();      try {          HttpResponse ht = hc.execute(httpGet);          if(ht.getStatusLine().getStatusCode() == HttpStatus.SC_OK){              HttpEntity he = ht.getEntity();              InputStream is = he.getContent();              BufferedReader br = new BufferedReader(new InputStreamReader(is));              String response = "";              String readLine = null;              while((readLine =br.readLine()) != null){                  //response = br.readLine();                  response = response + readLine;              }              is.close();              br.close();  

            //String str = EntityUtils.toString(he);              System.out.println("========="+response);              return response;          }else{              return "error";          }      } catch (ClientProtocolException e) {          // TODO Auto-generated catch block          e.printStackTrace();          return "exception";      } catch (IOException e) {          // TODO Auto-generated catch block          e.printStackTrace();          return "exception";      }      }  

public String doPost(String username,String password){      //String getUrl = urlAddress + "?username="+username+"&password="+password;      HttpPost httpPost = new HttpPost(urlAddress);      List params = new ArrayList();      NameValuePair pair1 = new BasicNameValuePair("username", username);      NameValuePair pair2 = new BasicNameValuePair("password", password);      params.add(pair1);      params.add(pair2);  

    HttpEntity he;      try {          he = new UrlEncodedFormEntity(params, "gbk");          httpPost.setEntity(he);  

    } catch (UnsupportedEncodingException e1) {          // TODO Auto-generated catch block          e1.printStackTrace();      }   

    HttpClient hc = new DefaultHttpClient();      try {          HttpResponse ht = hc.execute(httpPost);          //连接成功          if(ht.getStatusLine().getStatusCode() == HttpStatus.SC_OK){              HttpEntity het = ht.getEntity();              InputStream is = het.getContent();              BufferedReader br = new BufferedReader(new InputStreamReader(is));              String response = "";              String readLine = null;              while((readLine =br.readLine()) != null){                  //response = br.readLine();                  response = response + readLine;              }              is.close();              br.close();  

            //String str = EntityUtils.toString(he);              System.out.println("=========&&"+response);              return response;          }else{              return "error";          }      } catch (ClientProtocolException e) {          // TODO Auto-generated catch block          e.printStackTrace();          return "exception";      } catch (IOException e) {          // TODO Auto-generated catch block          e.printStackTrace();          return "exception";      }     }  

servlet端json转化： 

        resp.setContentType("text/json");          resp.setCharacterEncoding("UTF-8");          toDo = new ToDo();          List<UserBean> list = new ArrayList<UserBean>();          list = toDo.queryUsers(mySession);          String body;  

        //设定JSON          JSONArray array = new JSONArray();          for(UserBean bean : list)          {              JSONObject obj = new JSONObject();              try              {                   obj.put("username", bean.getUserName());                   obj.put("password", bean.getPassWord());               }catch(Exception e){}               array.add(obj);          }          pw.write(array.toString());          System.out.println(array.toString());  

android端接收：

String urlAddress = "http://192.168.1.102:8080/qualityserver/result.do";          String body =               getContent(urlAddress);          JSONArray array = new JSONArray(body);                    for(int i=0;i<array.length();i++)          {              obj = array.getJSONObject(i);              sb.append("用户名:").append(obj.getString("username")).append("\t");              sb.append("密码:").append(obj.getString("password")).append("\n");  

            HashMap<String, Object> map = new HashMap<String, Object>();              try {                  userName = obj.getString("username");                  passWord = obj.getString("password");              } catch (JSONException e) {                  e.printStackTrace();              }              map.put("username", userName);              map.put("password", passWord);              listItem.add(map);  

        }  

        } catch (Exception e) {              // TODO Auto-generated catch block              e.printStackTrace();          }  

        if(sb!=null)          {              showResult.setText("用户名和密码信息：");              showResult.setTextSize(20);          } else              extracted();  

       //设置adapter           SimpleAdapter simple = new SimpleAdapter(this,listItem,                  android.R.layout.simple_list_item_2,                  new String[]{"username","password"},                  new int[]{android.R.id.text1,android.R.id.text2});          listResult.setAdapter(simple);  

        listResult.setOnItemClickListener(new OnItemClickListener() {              @Override              public void onItemClick(AdapterView<?> parent, View view,                      int position, long id) {                  int positionId = (int) (id+1);                  Toast.makeText(MainActivity.this, "ID："+positionId, Toast.LENGTH_LONG).show();  

            }          });      }      private void extracted() {          showResult.setText("没有有效的数据！");      }      //和服务器连接      private String getContent(String url)throws Exception{          StringBuilder sb = new StringBuilder();          HttpClient client =new DefaultHttpClient();          HttpParams httpParams =client.getParams();  

        HttpConnectionParams.setConnectionTimeout(httpParams, 3000);          HttpConnectionParams.setSoTimeout(httpParams, 5000);          HttpResponse response = client.execute(new HttpGet(url));          HttpEntity entity =response.getEntity();  

        if(entity !=null){              BufferedReader reader = new BufferedReader(new InputStreamReader                      (entity.getContent(),"UTF-8"),8192);              String line =null;              while ((line= reader.readLine())!=null){                  sb.append(line +"\n");              }              reader.close();          }          return sb.toString();      }