android 应用的网络请求工具

       Android应用开发中一般会用到访问网络请求，可以使用socket，webservice等。这里我只是用java中URL，传送数据方式采用json，不考虑数据加密问题。封装的工具类很简单，只提供post，get方法。由于androidUI主线程中不允许启动线程，这里使用FutrueTask启动线程获得返回结果。代码如下：

public class HttpUtil {

/**
* get方式访问服务器
* @param url
* @param params
* @return
* @throws Exception
*/
public static String get(final String url, final Map<String, Object> params)throws Exception{
String r = null;
FutureTask<String> task = new FutureTask<String>(new Callable<String>() {
@Override
public String call() throws Exception {
BufferedReader bufferedReader = null;
String result = null;
try {
String getUrl = url + "?" + getParams(params);
Log.i("ApplicationTest", getUrl);
URL realUrl = new URL(getUrl);
URLConnection connection = realUrl.openConnection();
connection.connect();
bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = null;
StringBuffer sb = new StringBuffer();
while((line = bufferedReader.readLine())!=null){
sb.append(line);
}
result = sb.toString();
} catch (IOException e) {
Log.i("ApplicationTest", "xxxxx1");
e.printStackTrace();
throw e;
}finally {
if(bufferedReader != null){
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
});
new Thread(task).start();

try {
r = task.get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
return r;
}

/**
* post方式访问服务器
* @param url
* @param params
* @return
* @throws Exception
*/
public static String post(final String url, final Map<String, Object> params)throws Exception{
String r = null;
FutureTask<String> task = new FutureTask<String>(new Callable<String>() {
@Override
public String call() throws Exception {
String result = null;
BufferedReader bufferedReader = null;
PrintWriter out = null;
try {
String getUrl = url;
URL realUrl = new URL(getUrl);
URLConnection connection = realUrl.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
out = new PrintWriter(connection.getOutputStream());
out.print(getParams(params));
out.flush();
bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = null;
StringBuffer sb = new StringBuffer();
while((line = bufferedReader.readLine())!=null){
sb.append(line);
}
result = sb.toString();
} catch (IOException e) {
e.printStackTrace();
throw e;
}finally {
if(bufferedReader != null){
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

return result;
}
});

new Thread(task).start();
try {
r = task.get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
return r;
}

/**
* 组装请求参数
* @param params
* @return
*/
private static String getParams(Map<String, Object> params){
StringBuffer sb = new StringBuffer();
if(params != null){
for(String key : params.keySet()){
sb.append(key).append("=").append(params.get(key).toString()).append("&");
}
if(sb.indexOf("&") == sb.length()-1){
sb.deleteCharAt(sb.length()-1);
}
}
return sb.toString();
}

}

 如果使用HttpClient工具包，代码会更简单。这里就不列出。