大神来帮我看看把

Question

为什么第二个try的BufferedReader reader=new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
这句和is.close();这句话会出错呢
try{
         HttpClient httpclient=new DefaultHttpClient();
         HttpPost httppost=new HttpPost("http://110.86.69.250/getAllPeopleBornAfter.php");
         httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
         HttpResponse response =httpclient.execute(httppost);
         HttpEntity entity=response.getEntity();
         InputStream is=entity.getContent();
        }catch(Exception e){
         Log.e("log_tag", "Error in http connection" + e.toString());
        }
        try{
BufferedReader reader=new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
         StringBuilder sb=new StringBuilder();
         String line =null;
         while((line=reader.readLine())!=null){
         sb.append(line+"\n");
         }
         is.close();
         result=sb.toString();
        }catch(Exception e){
         Log.e("log_tag","Error converting result" + e.toString());
        }

Answer 1

我上面一个try定义了is了，下面就调用不了了吗？

Answer 2

将2个try合并成一个，例如try{
   HttpClient httpclient=new DefaultHttpClient();
   HttpPost httppost=new HttpPost("http://110.86.69.250/getAllPeopleBornAfter.php");
   httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
   HttpResponse response =httpclient.execute(httppost);
   HttpEntity entity=response.getEntity();
   InputStream is=entity.getContent();
 BufferedReader reader=new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
   StringBuilder sb=new StringBuilder();
   String line =null;
   while((line=reader.readLine())!=null){
   sb.append(line+"\n");
   }
   is.close();
   result=sb.toString();   
   }catch(Exception e){
   Log.e("log_tag", "Error in http connection" + e.toString());
   }

Answer 3

或者将is在try外部定义，这样2个try都可以用。InputStream is;
try{
   HttpClient httpclient=new DefaultHttpClient();
   HttpPost httppost=new HttpPost("http://110.86.69.250/getAllPeopleBornAfter.php");
   httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
   HttpResponse response =httpclient.execute(httppost);
   HttpEntity entity=response.getEntity();
   is=entity.getContent();
   }catch(Exception e){
   Log.e("log_tag", "Error in http connection" + e.toString());
   }
   try{
 BufferedReader reader=new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
   StringBuilder sb=new StringBuilder();
   String line =null;
   while((line=reader.readLine())!=null){
   sb.append(line+"\n");
   }
   is.close();
   result=sb.toString();
   }catch(Exception e){
   Log.e("log_tag","Error converting result" + e.toString());
   }