Android 开发工具类 25_getJSON

获取 JSON 数据并解析

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONObject;

import com.wangjialin.internet.json.domain.News;
import com.wangjialin.internet.json.utils.StreamTool;

public class NewsService {
    
    /**
     * 获取最新视频资讯
     * @return
     * @throws Exception
     */
    public static List<News> getJSONLastNews() throws Exception{
        
        String path = "http://192.168.1.103:8080/ServerForJSON/NewsListServlet";
        HttpURLConnection conn = (HttpURLConnection) new URL(path).openConnection();
        conn.setConnectTimeout(5000);
        conn.setRequestMethod("GET");
        
        if(conn.getResponseCode() == 200){
            InputStream json = conn.getInputStream();
            return parseJSON(json);
        }
        return null;
    }
    
    private static List<News> parseJSON(InputStream jsonStream) throws Exception{
        
        List<News> list = new ArrayList<News>();
        byte[] data = StreamTool.read(jsonStream);
        String json = new String(data);
        JSONArray jsonArray = new JSONArray(json);
        
        for(int i = 0; i < jsonArray.length() ; i++){
            JSONObject jsonObject = jsonArray.getJSONObject(i);
            int id = jsonObject.getInt("id");
            String title = jsonObject.getString("title");
            int timelength = jsonObject.getInt("timelength");
            list.add(new News(id, title, timelength));
        }
        return list;
    }
}

StreamTool

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

public class StreamTool {
    /**
     * 从流中读取数据
     * @param inStream
     * @return
     */
    public static byte[] read(InputStream inStream) throws Exception{
        
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        
        while((len = inStream.read(buffer)) != -1){
            outputStream.write(buffer, 0, len);
        }
        
        inStream.close();
        return outputStream.toByteArray();
    }
}

显示

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    List<News> newes;
    List<HashMap<String, Object>> data = null;;
    String length;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        setContentView(R.layout.main);
        ListView listView = (ListView) this.findViewById(R.id.listView);
        
        length = this.getResources().getString(R.string.length);
        
        try{
            newes = NewsService.getJSONLastNews();
            data = new ArrayList<HashMap<String,Object>>();
            for(News news : newes){
                HashMap<String, Object> item = new HashMap<String, Object>();
                item.put("id", news.getId());
                item.put("title", news.getTitle());
                item.put("timelength", length + news.getTimelength());
                data.add(item);
            }                
        
            SimpleAdapter adapter = new SimpleAdapter(this, 
                    data, R.layout.item,
                    new String[]{"title", "timelength"}, 
                    new int[]{R.id.title, R.id.timelength}
            );
            listView.setAdapter(adapter);        
        }catch(Exception e)
        {
            e.printStackTrace();
        };
    }
}