安卓开发网络数据请求

1将访问的路径转换成URL。
URL url =  new  URL(path);
2，通过URL获取连接。
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
3，设置请求方式

conn.setRequestMethod("GET");
4，设置连接超时时间

conn.setConnectTimeout( 5000 );
5，设置读取时间
conn.setConnectTimeout(5000);
6，设置请求头的信息。

conn.setRequestProperty(User-Agent, Mozilla/ 5.0  (compatible; MSIE  9.0 ; Windows NT  6.1 ; Trident/ 5.0 ));
7，获取响应码

if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {              InputStream  is = conn.getInputStream();             }
8，请求码200，表明请求成功，获取返回内容的输入流

/**

     * 将输入流转换成字符串
     *
     * @param is
     *            从网络获取的输入流
     * @return
     */
    public  static  String streamToString(InputStream is) {
        try  {
            ByteArrayOutputStream baos =  new  ByteArrayOutputStream();
            byte [] buffer =  new  byte [ 1024 ];
            int  len =  0 ;
            while  ((len = is.read(buffer)) != - 1 ) {
                baos.write(buffer,  0 , len);
            }
            baos.close();
            is.close();
            byte [] byteArray = baos.toByteArray();
            return  new  String(byteArray);
        }  catch  (Exception e) {
            Log.e(tag, e.toString());
            return  null ;
        }
    }
　　 HttpUrlConnection

/**
     * 通过HttpUrlConnection发送GET请求
     *
     * @param username
     * @param password
     * @return
     */
    public  static  String loginByGet(String username, String password) {
        String path = http: //192.168.0.107:8080/WebTest/LoginServerlet?username= + username + &password= + password;
        try  {
            URL url =  new  URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setConnectTimeout( 5000 );
            conn.setRequestMethod(GET);
            int  code = conn.getResponseCode();
            if  (code ==  200 ) {
                InputStream is = conn.getInputStream();  // 字节流转换成字符串
                return  StreamTools.streamToString(is);
            }  else  {
                return  网络访问失败;
            }
        }  catch  (Exception e) {
            e.printStackTrace();
            return  网络访问失败;
        }

/**
     * 通过HttpUrlConnection发送POST请求
     *
     * @param username
     * @param password
     * @return
     */
    public  static  String loginByPost(String username, String password) {
        String path = http: //192.168.0.107:8080/WebTest/LoginServerlet;
        try  {
            URL url =  new  URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setConnectTimeout( 5000 );
            conn.setRequestMethod(POST);
            conn.setRequestProperty(Content-Type, application/x-www-form-urlencoded);
            String data = username= + username + &password= + password;
            conn.setRequestProperty(Content-Length, data.length() + );
            // POST方式，其实就是浏览器把数据写给服务器
            conn.setDoOutput( true );  // 设置可输出流
            OutputStream os = conn.getOutputStream();  // 获取输出流
            os.write(data.getBytes());  // 将数据写给服务器
            int  code = conn.getResponseCode();
            if  (code ==  200 ) {
                InputStream is = conn.getInputStream();
                return  StreamTools.streamToString(is);
            }  else  {
                return  网络访问失败;
            }
        }  catch  (Exception e) {
            e.printStackTrace();
            return  网络访问失败;
        }
    }

HttpClient

/**
     * 通过HttpClient发送GET请求
     *
     * @param username
     * @param password
     * @return
     */
    public  static  String loginByHttpClientGet(String username, String password) {
        String path = http: //192.168.0.107:8080/WebTest/LoginServerlet?username=
                + username + &password= + password;
        HttpClient client =  new  DefaultHttpClient();  // 开启网络访问客户端
        HttpGet httpGet =  new  HttpGet(path);  // 包装一个GET请求
        try  {
            HttpResponse response = client.execute(httpGet);  // 客户端执行请求
            int  code = response.getStatusLine().getStatusCode();  // 获取响应码
            if  (code ==  200 ) {
                InputStream is = response.getEntity().getContent();  // 获取实体内容
                String result = StreamTools.streamToString(is);  // 字节流转字符串
                return  result;
            }  else  {
                return  网络访问失败;
            }
        }  catch  (Exception e) {
            e.printStackTrace();
            return  网络访问失败;
        }
    }

/**
     * 通过HttpClient发送POST请求
     *
     * @param username
     * @param password
     * @return
     */
    public  static  String loginByHttpClientPOST(String username, String password) {
        String path = http: //192.168.0.107:8080/WebTest/LoginServerlet;
        try  {
            HttpClient client =  new  DefaultHttpClient();  // 建立一个客户端
            HttpPost httpPost =  new  HttpPost(path);  // 包装POST请求
            // 设置发送的实体参数
            List parameters =  new  ArrayList();
            parameters.add( new  BasicNameValuePair(username, username));
            parameters.add( new  BasicNameValuePair(password, password));
            httpPost.setEntity( new  UrlEncodedFormEntity(parameters, UTF- 8 ));
            HttpResponse response = client.execute(httpPost);  // 执行POST请求
            int  code = response.getStatusLine().getStatusCode();
            if  (code ==  200 ) {
                InputStream is = response.getEntity().getContent();
                String result = StreamTools.streamToString(is);
                return  result;
            }  else  {
                return  网络访问失败;
            }
        }  catch  (Exception e) {
            e.printStackTrace();
            return  访问网络失败;
        }
    }