问如何通过此函数获取json字符串的值并进行解析

EN

private String getServerData(String returnString) {

       InputStream is = null;

       String result = "";
        //the year data to send
        ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
        nameValuePairs.add(new BasicNameValuePair("year","1970"));

        //http post
        try{
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost(KEY_121);
                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());
        }

        //convert response to string
        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());
        }

        try{
                JSONArray jArray = new JSONArray(result);
                for(int i=0;i<jArray.length();i++){
                   // JSONObject json_data = jArray.getJSONObject(i);
                    JSONObject json_data = jArray.getJSONObject(i);
                    Log.i("log_tag","id: "+json_data.getInt("id")+
                            ", name: "+json_data.getString("name")+
                            ", sex: "+json_data.getInt("sex")+
                            ", birthyear: "+json_data.getInt("birthyear")
                    );


                        //Get an output to the screen
                        returnString += "\n\t" + jArray.getJSONObject(i); 
                }
        }catch(JSONException e){
                Log.e("log_tag", "Error parsing data "+e.toString());

                returnString += result.toString();
        }
        return returnString; 
    }   

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ListView listView = (ListView)findViewById(R.id.list);
        myBooks = new ArrayList<HashMap<String,Object>>();
        HashMap<String, Object> hm;
        hm = new HashMap<String, Object>();
        List<String> list=new ArrayList<String>();
        list.add(getServerData(KEY_121));





        //With the help of HashMap add Key, Values of Book, like name,price and icon path 
       /* hm = new HashMap<String, Object>();
        hm.put(BOOKKEY, "Android");
        hm.put(PRICEKEY, "Price Rs: 500");
        hm.put(IMGKEY, R.raw.android); //i have images in res/raw folder

        myBooks.add(hm);


 SimpleAdapter adapter = new SimpleAdapter(this, myBooks, R.layout.listbox, 
                new String[]{BOOKKEY,PRICEKEY,IMGKEY}, new int[]{R.id.text1, R.id.text2, R.id.img});

        listView.setAdapter(adapter);
        listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE); 
    }