《Android开发卷——HTTP网络通信,HTTP网络连接》

为了访问互联网，需要设置应用程序获取“androd.permission.INTERNET”权限的许可。

一、使用Apache接口（org.apache.http）并实现网络连接的基本知识

HttpClient client = new DefaultHttpClient();

要想从服务器检索有用的网络信息，必须使用HttpGet类构造器来帮助实现

HttpGet request = new HttpGet(“http://www.*****.com/test?id=***&name=****”);

然后还需要类HttpClient的execute()方法的帮助，通过此方法中的HttpGet对象来检索

HttpResponse response = client.execute(request);

最后需要解读已检索的响应(读取网页内容)

BufferedReader rd = new BufferedRreader(new InputStreamReader(response.getEntity().getContent()));

String line = “”;

While((line = rd.readLine()) != null){

Log.d(“output:”,line);

line = line+line;

}

 

Post方法

HttpClient client = new DafaultHttpClient();
HttpPost post = new HttpPost(URL);
List<NameValuePair> parms = new ArrayList<NameValuePair>();
parms.add(new NameValuePair(“id”,”1001”));
parms.add(new NameValuePair(“name”,”johm”));
HttpEntity formEntity = new UrlEncodeFormEntity(params);
post.setEntity(formEntity,HTTP.UTF_8);
Httpresponse response = new client.execute(post); 
If(response.getStatusLine.getStatusCode == HttpStatus.SC_OK){
InputStream is = response.getEntity().getContent();
String result = isStreamString(is);
Assert.assertEqualse(result,”POST_SUCCESS”);//断言判断网页返回的内容是否为” POST_SUCCESS”;
}
 
private String isStreamString(InputStream is) throws Exception{
ByteArrayOutputStream bo = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int len = -1;
while((len = is.read(buf)) != -1){
bo.write(buf,0,len);
}
return new String(bo.toByteArray());
}

在文件MyApplication.java中扩展了系统的Application:

public class MyApplication extends Application{
private HttpClient httpClient;
public void onCreate(){
super.onCreate();
httpClient = this.createHttpClient();
} 
public void onLowMemory(){
super.onLowMemory();
this.shutdownHttpClient();
}
public void onTerminamte(){
super.onTerminate();
this.shutdownHttpClient();
}
//创建HttpClient实例
private HttpClient createHttpClient(){
HttpParams params = new BasicHttpParams();
HttpProtocolParams.setversion(params,HttpVersion.HTTP_1_1);
HttpProtocolParams.setContentCharset(params,HTTP.DEFAULT_CONTENT_CHARSET);
HttpProtocolParams.setUseExpectContinue(params,true);
 
SchemeRegistry schReg = new SchemeRegistry();
schReg.register(“http”,PlainSocketFactory.getSocketFactory(),80);
schReg.register(“https”,SSLSocketFatory.getSocketFactory(),443);
 
ClientConnectionManager connMgr = new ThreadSafeClientConnManager(params,schReg);
return new DefaultHttpClient(connMgr,params);
}
//关闭连接管理器并释放资源
private void shutdownHttpClient(){
if(httpClient != null && httpClient.getConnectionManager() != null){
httpClient.getConnectionManager().shutdown();
}
//对外提供HttpClient实例
public HttpClient getHttpClient(){
return httpClient;
}
}

在上述代码中重写了onCreate()方法，在系统启动时就创建一个HttpClient。

重写了onLowMemory()和onTerminate()方法，在内存不足和应用结束时关闭连接，释放资源。

需要注意的是，当实例化DefaultHttpClient时，传入一个由ThreadSafeClientConnManager创建的ClientConnectionManager实例，负责管理HttpClient的HTTP连接。

在文件AndroidManifest.xml中进行如下配置，目的是让“优化”版的Application生效。

<application android:name=”.MyApplication”…>…</application>

系统就会使用前面编写的MyApplication，然后就可以在context中调用getApplication()来获取MyApplication实例。

 

经过上面的“优化”处理配置，接下来就可以在活动中应用了

private void execute(){
try{
MyApplication app = (MyApplication) this.getApplication();
 
HttpClient client = app.getHttpClient();
HttpGet request = new HttpGet(“http://www.*****.com/test?id=***&name=****”); 
HttpResponse response = client.execute(request);
if(response.getStatusLine.getStatusCode == HttpStatus.SC_OK){
InputStream is = response.getEntity().getContent();
String result = isStreamString(is);
Toast.makeText(this,result,Toast.LENGTH_LONG).show();
}
}catch(Exception e){
e.printStackTrace();
}
}
private String isStreamString(InputStream is) throws Exception{
ByteArrayOutputStream bo = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int len = -1;
while((len = is.read(buf)) != -1){
bo.write(but,0,len);
}
return new String(bo.toByteArray());
}

尊重原创,转载请注明出处:http://blog.csdn.net/chillax_li/article/details/22078625