android 网络编程
// 原文出处 http://lpqsun-126-com.iteye.com/blog/1084311
Android中提供的HttpURLConnection和HttpClient接口可以用来开发HTTP程序。以下是本人在学习中的总结与归纳。
1. HttpURLConnection接口
首先需要明确的是,Http通信中的POST和GET请求方式的不同。GET可以获得静态页面,也可以把参数放在URL字符串后面,传递给服务器。而POST方法的参数是放在Http请求中。因此,在编程之前,应当首先明确使用的请求方法,然后再根据所使用的方式选择相应的编程方式。
HttpURLConnection是继承于URLConnection类,二者都是抽象类。其对象主要通过URL的openConnection方法获得。创建方法如下代码所示:
- URL url = new URL("http://www.51cto.com/index.jsp?par=123456");
- HttpURLConnection urlConn=(HttpURLConnection)url.openConnection();
URL url = new URL("http://www.51cto.com/index.jsp?par=123456"); HttpURLConnection urlConn=(HttpURLConnection)url.openConnection();
通过以下方法可以对请求的属性进行一些设置,如下所示
- //设置输入和输出流
- urlConn.setDoOutput(true);
- urlConn.setDoInput(true);
- //设置请求方式为POST
- urlConn.setRequestMethod("POST");
- //POST请求不能使用缓存
- urlConn.setUseCaches(false);
- //关闭连接
- urlConn.disConnection();
//设置输入和输出流 urlConn.setDoOutput(true); urlConn.setDoInput(true); //设置请求方式为POST urlConn.setRequestMethod("POST"); //POST请求不能使用缓存 urlConn.setUseCaches(false); //关闭连接 urlConn.disConnection();
Manifest文件中权限的设定:
- <uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.INTERNET" />
HttpURLConnection默认使用GET方式,例如下面代码所示:
- //以Get方式上传参数
- public class Activity03 extends Activity
- {
- private final String DEBUG_TAG = "Activity03";
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState)
- {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.http);
- TextView mTextView = (TextView)this.findViewById(R.id.TextView_HTTP);
- //http地址"?par=abcdefg"是我们上传的参数
- String httpUrl = "http://192.168.1.110:8080/httpget.jsp?par=abcdefg";
- //获得的数据
- String resultData = "";
- URL url = null;
- try
- {
- //构造一个URL对象
- url = new URL(httpUrl);
- }
- catch (MalformedURLException e)
- {
- Log.e(DEBUG_TAG, "MalformedURLException");
- }
- if (url != null)
- {
- try
- {
- // 使用HttpURLConnection打开连接
- HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
- //得到读取的内容(流)
- InputStreamReader in = new InputStreamReader(urlConn.getInputStream());
- // 为输出创建BufferedReader
- BufferedReader buffer = new BufferedReader(in);
- String inputLine = null;
- //使用循环来读取获得的数据
- while (((inputLine = buffer.readLine()) != null))
- {
- //我们在每一行后面加上一个"\n"来换行
- resultData += inputLine + "\n";
- }
- //关闭InputStreamReader
- in.close();
- //关闭http连接
- urlConn.disconnect();
- //设置显示取得的内容
- if ( resultData != null )
- {
- mTextView.setText(resultData);
- }
- else
- {
- mTextView.setText("读取的内容为NULL");
- }
- }
- catch (IOException e)
- {
- Log.e(DEBUG_TAG, "IOException");
- }
- }
- else
- {
- Log.e(DEBUG_TAG, "Url NULL");
- }
- }
//以Get方式上传参数 public class Activity03 extends Activity { private final String DEBUG_TAG = "Activity03"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.http); TextView mTextView = (TextView)this.findViewById(R.id.TextView_HTTP); //http地址"?par=abcdefg"是我们上传的参数 String httpUrl = "http://192.168.1.110:8080/httpget.jsp?par=abcdefg"; //获得的数据 String resultData = ""; URL url = null; try { //构造一个URL对象 url = new URL(httpUrl); } catch (MalformedURLException e) { Log.e(DEBUG_TAG, "MalformedURLException"); } if (url != null) { try { // 使用HttpURLConnection打开连接 HttpURLConnection urlConn = (HttpURLConnection) url.openConnection(); //得到读取的内容(流) InputStreamReader in = new InputStreamReader(urlConn.getInputStream()); // 为输出创建BufferedReader BufferedReader buffer = new BufferedReader(in); String inputLine = null; //使用循环来读取获得的数据 while (((inputLine = buffer.readLine()) != null)) { //我们在每一行后面加上一个"\n"来换行 resultData += inputLine + "\n"; } //关闭InputStreamReader in.close(); //关闭http连接 urlConn.disconnect(); //设置显示取得的内容 if ( resultData != null ) { mTextView.setText(resultData); } else { mTextView.setText("读取的内容为NULL"); } } catch (IOException e) { Log.e(DEBUG_TAG, "IOException"); } } else { Log.e(DEBUG_TAG, "Url NULL"); } }
如果需要使用POST方式,则需要setRequestMethod设置。代码如下:
- //以post方式上传参数
- public class Activity04 extends Activity
- {
- private final String DEBUG_TAG = "Activity04";
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState)
- {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.http);
- TextView mTextView = (TextView)this.findViewById(R.id.TextView_HTTP);
- //http地址"?par=abcdefg"是我们上传的参数
- String httpUrl = "http://192.168.1.110:8080/httpget.jsp";
- //获得的数据
- String resultData = "";
- URL url = null;
- try
- {
- //构造一个URL对象
- url = new URL(httpUrl);
- }
- catch (MalformedURLException e)
- {
- Log.e(DEBUG_TAG, "MalformedURLException");
- }
- if (url != null)
- {
- try
- {
- // 使用HttpURLConnection打开连接
- HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
- //因为这个是post请求,设立需要设置为true
- urlConn.setDoOutput(true);
- urlConn.setDoInput(true);
- // 设置以POST方式
- urlConn.setRequestMethod("POST");
- // Post 请求不能使用缓存
- urlConn.setUseCaches(false);
- urlConn.setInstanceFollowRedirects(true);
- // 配置本次连接的Content-type,配置为application/x-www-form-urlencoded的
- urlConn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
- // 连接,从postUrl.openConnection()至此的配置必须要在connect之前完成,
- // 要注意的是connection.getOutputStream会隐含的进行connect。
- urlConn.connect();
- //DataOutputStream流
- DataOutputStream out = new DataOutputStream(urlConn.getOutputStream());
- //要上传的参数
- String content = "par=" + URLEncoder.encode("ABCDEFG", "gb2312");
- //将要上传的内容写入流中
- out.writeBytes(content);
- //刷新、关闭
- out.flush();
- out.close();
- //获取数据
- BufferedReader reader = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
- String inputLine = null;
- //使用循环来读取获得的数据
- while (((inputLine = reader.readLine()) != null))
- {
- //我们在每一行后面加上一个"\n"来换行
- resultData += inputLine + "\n";
- }
- reader.close();
- //关闭http连接
- urlConn.disconnect();
- //设置显示取得的内容
- if ( resultData != null )
- {
- mTextView.setText(resultData);
- }
- else
- {
- mTextView.setText("读取的内容为NULL");
- }
- }
- catch (IOException e)
- {
- Log.e(DEBUG_TAG, "IOException");
- }
- }
- else
- {
- Log.e(DEBUG_TAG, "Url NULL");
- }
- }
- }
//以post方式上传参数 public class Activity04 extends Activity { private final String DEBUG_TAG = "Activity04"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.http); TextView mTextView = (TextView)this.findViewById(R.id.TextView_HTTP); //http地址"?par=abcdefg"是我们上传的参数 String httpUrl = "http://192.168.1.110:8080/httpget.jsp"; //获得的数据 String resultData = ""; URL url = null; try { //构造一个URL对象 url = new URL(httpUrl); } catch (MalformedURLException e) { Log.e(DEBUG_TAG, "MalformedURLException"); } if (url != null) { try { // 使用HttpURLConnection打开连接 HttpURLConnection urlConn = (HttpURLConnection) url.openConnection(); //因为这个是post请求,设立需要设置为true urlConn.setDoOutput(true); urlConn.setDoInput(true); // 设置以POST方式 urlConn.setRequestMethod("POST"); // Post 请求不能使用缓存 urlConn.setUseCaches(false); urlConn.setInstanceFollowRedirects(true); // 配置本次连接的Content-type,配置为application/x-www-form-urlencoded的 urlConn.setRequestProperty("Content-Type","application/x-www-form-urlencoded"); // 连接,从postUrl.openConnection()至此的配置必须要在connect之前完成, // 要注意的是connection.getOutputStream会隐含的进行connect。 urlConn.connect(); //DataOutputStream流 DataOutputStream out = new DataOutputStream(urlConn.getOutputStream()); //要上传的参数 String content = "par=" + URLEncoder.encode("ABCDEFG", "gb2312"); //将要上传的内容写入流中 out.writeBytes(content); //刷新、关闭 out.flush(); out.close(); //获取数据 BufferedReader reader = new BufferedReader(new InputStreamReader(urlConn.getInputStream())); String inputLine = null; //使用循环来读取获得的数据 while (((inputLine = reader.readLine()) != null)) { //我们在每一行后面加上一个"\n"来换行 resultData += inputLine + "\n"; } reader.close(); //关闭http连接 urlConn.disconnect(); //设置显示取得的内容 if ( resultData != null ) { mTextView.setText(resultData); } else { mTextView.setText("读取的内容为NULL"); } } catch (IOException e) { Log.e(DEBUG_TAG, "IOException"); } } else { Log.e(DEBUG_TAG, "Url NULL"); } } }
2. HttpClient接口
使用Apache提供的HttpClient接口同样可以进行HTTP操作。
对于GET和POST请求方法的操作有所不同。GET方法的操作代码示例如下:
- public class Activity02 extends Activity
- {
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState)
- {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.http);
- TextView mTextView = (TextView) this.findViewById(R.id.TextView_HTTP);
- // http地址
- String httpUrl = "http://192.168.1.110:8080/httpget.jsp?par=HttpClient_android_Get";
- //HttpGet连接对象
- HttpGet httpRequest = new HttpGet(httpUrl);
- try
- {
- //取得HttpClient对象
- HttpClient httpclient = new DefaultHttpClient();
- //请求HttpClient,取得HttpResponse
- HttpResponse httpResponse = httpclient.execute(httpRequest);
- //请求成功
- if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK)
- {
- //取得返回的字符串
- String strResult = EntityUtils.toString(httpResponse.getEntity());
- mTextView.setText(strResult);
- }
- else
- {
- mTextView.setText("请求错误!");
- }
- }
- catch (ClientProtocolException e)
- {
- mTextView.setText(e.getMessage().toString());
- }
- catch (IOException e)
- {
- mTextView.setText(e.getMessage().toString());
- }
- catch (Exception e)
- {
- mTextView.setText(e.getMessage().toString());
- }
- }
- }
public class Activity02 extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.http); TextView mTextView = (TextView) this.findViewById(R.id.TextView_HTTP); // http地址 String httpUrl = "http://192.168.1.110:8080/httpget.jsp?par=HttpClient_android_Get"; //HttpGet连接对象 HttpGet httpRequest = new HttpGet(httpUrl); try { //取得HttpClient对象 HttpClient httpclient = new DefaultHttpClient(); //请求HttpClient,取得HttpResponse HttpResponse httpResponse = httpclient.execute(httpRequest); //请求成功 if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { //取得返回的字符串 String strResult = EntityUtils.toString(httpResponse.getEntity()); mTextView.setText(strResult); } else { mTextView.setText("请求错误!"); } } catch (ClientProtocolException e) { mTextView.setText(e.getMessage().toString()); } catch (IOException e) { mTextView.setText(e.getMessage().toString()); } catch (Exception e) { mTextView.setText(e.getMessage().toString()); } } }
使用POST方法进行参数传递时,需要使用NameValuePair来保存要传递的参数,另外,还需要设置所使用的字符集。代码如下所示:
- public class Activity03 extends Activity
- {
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState)
- {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.http);
- TextView mTextView = (TextView) this.findViewById(R.id.TextView_HTTP);
- // http地址
- String httpUrl = "http://192.168.1.110:8080/httpget.jsp";
- //HttpPost连接对象
- HttpPost httpRequest = new HttpPost(httpUrl);
- //使用NameValuePair来保存要传递的Post参数
- List<NameValuePair> params = new ArrayList<NameValuePair>();
- //添加要传递的参数
- params.add(new BasicNameValuePair("par", "HttpClient_android_Post"));
- try
- {
- //设置字符集
- HttpEntity httpentity = new UrlEncodedFormEntity(params, "gb2312");
- //请求httpRequest
- httpRequest.setEntity(httpentity);
- //取得默认的HttpClient
- HttpClient httpclient = new DefaultHttpClient();
- //取得HttpResponse
- HttpResponse httpResponse = httpclient.execute(httpRequest);
- //HttpStatus.SC_OK表示连接成功
- if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK)
- {
- //取得返回的字符串
- String strResult = EntityUtils.toString(httpResponse.getEntity());
- mTextView.setText(strResult);
- }
- else
- {
- mTextView.setText("请求错误!");
- }
- }
- catch (ClientProtocolException e)
- {
- mTextView.setText(e.getMessage().toString());
- }
- catch (IOException e)
- {
- mTextView.setText(e.getMessage().toString());
- }
- catch (Exception e)
- {
- mTextView.setText(e.getMessage().toString());
- }
- }
- }
public class Activity03 extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.http); TextView mTextView = (TextView) this.findViewById(R.id.TextView_HTTP); // http地址 String httpUrl = "http://192.168.1.110:8080/httpget.jsp"; //HttpPost连接对象 HttpPost httpRequest = new HttpPost(httpUrl); //使用NameValuePair来保存要传递的Post参数 List<NameValuePair> params = new ArrayList<NameValuePair>(); //添加要传递的参数 params.add(new BasicNameValuePair("par", "HttpClient_android_Post")); try { //设置字符集 HttpEntity httpentity = new UrlEncodedFormEntity(params, "gb2312"); //请求httpRequest httpRequest.setEntity(httpentity); //取得默认的HttpClient HttpClient httpclient = new DefaultHttpClient(); //取得HttpResponse HttpResponse httpResponse = httpclient.execute(httpRequest); //HttpStatus.SC_OK表示连接成功 if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { //取得返回的字符串 String strResult = EntityUtils.toString(httpResponse.getEntity()); mTextView.setText(strResult); } else { mTextView.setText("请求错误!"); } } catch (ClientProtocolException e) { mTextView.setText(e.getMessage().toString()); } catch (IOException e) { mTextView.setText(e.getMessage().toString()); } catch (Exception e) { mTextView.setText(e.getMessage().toString()); } } }
HttpClient实际上是对Java提供方法的一些封装,在HttpURLConnection中的输入输出流操作,在这个接口中被统一封装成了HttpPost(HttpGet)和HttpResponse,这样,就减少了操作的繁琐性。
另外,在使用POST方式进行传输时,需要进行字符编码