android 连接网络
http://senior.ceng.metu.edu.tr/2009/praeda/2009/01/11/a-simple-restful-client-at-android/
http://senior.ceng.metu.edu.tr/2009/praeda/2009/01/11/a-simple-restful-client-at-android/
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
package praeda.muzikmekan;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class RestClient {
private static String convertStreamToString(InputStream is) {
/*
* To convert the InputStream to String we use the BufferedReader.readLine()
* method. We iterate until the BufferedReader return null which means
* there's no more data to read. Each line will appended to a StringBuilder
* and returned as String.
*/
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
/* This is a test function which will connects to a given
* rest service and prints it's response to Android Log with
* labels "Praeda".
*/
public static void connect(String url)
{
HttpClient httpclient = new DefaultHttpClient();
// Prepare a request object
HttpGet httpget = new HttpGet(url);
// Execute the request
HttpResponse response;
try {
response = httpclient.execute(httpget);
// Examine the response status
Log.i("Praeda",response.getStatusLine().toString());
// Get hold of the response entity
HttpEntity entity = response.getEntity();
// If the response does not enclose an entity, there is no need
// to worry about connection release
if (entity != null) {
// A Simple JSON Response Read
InputStream instream = entity.getContent();
String result= convertStreamToString(instream);
Log.i("Praeda",result);
// A Simple JSONObject Creation
JSONObject json=new JSONObject(result);
Log.i("Praeda","<jsonobject>\n"+json.toString()+"\n</jsonobject>");
// A Simple JSONObject Parsing
JSONArray nameArray=json.names();
JSONArray valArray=json.toJSONArray(nameArray);
for(int i=0;i<valArray.length();i++)
{
Log.i("Praeda","<jsonname"+i+">\n"+nameArray.getString(i)+"\n</jsonname"+i+">\n"
+"<jsonvalue"+i+">\n"+valArray.getString(i)+"\n</jsonvalue"+i+">");
}
// A Simple JSONObject Value Pushing
json.put("sample key", "sample value");
Log.i("Praeda","<jsonobject>\n"+json.toString()+"\n</jsonobject>");
// Closing the input stream will trigger connection release
instream.close();
}
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
2.如果你要连接两次那么一定记得加上：
System.setProperty("http.keepAlive", "false")
3.测试代码
public static String get(String url) throws IOException {
ByteArrayOutputStream os = new ByteArrayOutputStream();
URLConnection conn=null;
byte[] buf = new byte[4096];
try {
URL a = new URL(url);
conn = a.openConnection();
InputStream is = conn.getInputStream();
int ret = 0;
while ((ret = is.read(buf)) > 0) {
os.write(buf, 0, ret);
}
// close the inputstream
is.close();
return new String(os.toByteArray());
} catch (IOException e) {
try {
int respCode = ((HttpURLConnection)conn).getResponseCode();
InputStream es = ((HttpURLConnection)conn).getErrorStream();
int ret = 0;
// read the response body
while ((ret = es.read(buf)) > 0) {
os.write(buf, 0, ret);
}
// close the errorstream
es.close();
return "Error response " + respCode + ": " +
new String(os.toByteArray());
} catch(IOException ex) {
throw ex;
}
}
}
try {
URL url = new URL("http://"+params[0]);
HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
urlc.setRequestProperty("User-Agent", "Android Application:"+Z.APP_VERSION);
urlc.setRequestProperty("Connection", "close");
urlc.setConnectTimeout(1000 * 30); // mTimeout is in seconds
urlc.connect();
if (urlc.getResponseCode() == 200) {
Main.Log("getResponseCode == 200");
return new Boolean(true);
}
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
常用方法有
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ByteArrayEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
try {
int TIMEOUT_MILLISEC = 10000; // = 10 seconds
HttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams,
TIMEOUT_MILLISEC);
HttpConnectionParams.setSoTimeout(httpParams, TIMEOUT_MILLISEC);
HttpClient client = new DefaultHttpClient(httpParams);
HttpPost request = new HttpPost(serverUrl);
request.setEntity(new ByteArrayEntity(
postMessage.toString().getBytes("UTF8")));
HttpResponse response = client.execute(request);
} catch (Exception e) {
....
}