我想显示包含特定子字符串的视频标题，例如 videoName="apple":
因此，为了执行此任务，我编写了一段代码来检索 Json 文件并获取与该名称相关的所有条目:("https://gdata.youtube.com/feeds/api/videos?q= "+videoName+"&v=2&alt=json") 但不幸的是，我对此声明有异常(exception):
HttpResponse res = cli.execute(g);
这是我写的获取json文件的函数:
String GetUrlBody (String Url ){
Log.d("s18", "ok");
HttpClient cli = new DefaultHttpClient();
Log.d("s19", "ok");
HttpGet g = new HttpGet(Url);
Log.d("s20", "ok");
try{
Log.d("s21", "ok");
HttpResponse res = cli.execute(g);
Log.d("s22", "ok");
if(res.getStatusLine().getStatusCode() == 200){
Log.d("s23", "ok");
String s =
EntityUtils.toString(res.getEntity(), HTTP.UTF_8);
Log.d("s24", "ok");
return s;
}else {
Log.d("s25", "ok");
return "Not Found";
}
}catch(Exception exx){
Log.d("s26", "ok");
Log.d("s27", exx.getMessage());
}
return null;
}
我所有的代码:
package com.example.task_10_vedioserach;
import java.util.ArrayList;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONTokener;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
public class MainActivity extends Activity {
ListView vediolist;
ImageButton search;
Button history;
EditText title;
/////////////////
ArrayList<String > vl;
ArrayAdapter< String > ad ;
ProgressDialog pd ;
/////////////////
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
vediolist = (ListView) findViewById(R.id.vedioList);
search = (ImageButton) findViewById(R.id.search);
history = (Button) findViewById(R.id.history);
title=(EditText) findViewById(R.id.vedioName);
/////////////////////////////////////////////////////////////////
vl = new ArrayList<String>();
ad = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1 , android.R.id.text1,vl);
//////////////////////////////////////////////////////////////
Log.d("s0", "ok");
search.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final String vedioName=title.getText().toString();
Log.d("s1", "ok");
new conn().execute("https://gdata.youtube.com/feeds/api/videos?q="+vedioName+"&v=2&alt=json");
Log.d("s2", "ok");
}
});
pd = new ProgressDialog(this);
pd.setMessage("Wait Loading .... ");
pd.setCancelable(false);
vediolist.setAdapter(ad);
}
class conn extends AsyncTask<String, Integer, String>{
@Override
protected void onPreExecute() {
Log.d("s3", "ok");
pd.show();
super.onPreExecute();
Log.d("s4", "ok");
}
@Override
protected String doInBackground(String... arg0) {
Log.d("s5", "ok");
String s = GetUrlBody(arg0[0]);
Log.d("s6", "ok");
return s;
}
@Override
protected void onPostExecute(String result) {
Log.d("s7", "ok");
try{
Log.d("s8", "ok");
JSONObject jo =(JSONObject) new JSONTokener(result).nextValue();
Log.d("s9", "ok");
JSONObject feed = jo.optJSONObject("feed");
Log.d("s10", "ok");
JSONArray ent = feed.optJSONArray("entry");
Log.d("s11", "ok");
for(int i = 0 ; i<ent.length() ; i++){
String ti = ent.getJSONObject(i).
getJSONObject("title").getString("$t");
vl.add(ti);
}
Log.d("s12", "ok");
ad.notifyDataSetChanged();
Log.d("s13", "ok");
}catch(Exception exx) {
Log.d("s14", "ok");
}
Log.d("s15", "ok");
pd.dismiss();
Log.d("s16", "ok");
super.onPostExecute(result);
Log.d("s17", "ok");
}
String GetUrlBody (String Url ){
Log.d("s18", "ok");
HttpClient cli = new DefaultHttpClient();
Log.d("s19", "ok");
HttpGet g = new HttpGet(Url);
Log.d("s20", "ok");
try{
Log.d("s21", "ok");
HttpResponse res = cli.execute(g);
Log.d("s22", "ok");
if(res.getStatusLine().getStatusCode() == 200){
Log.d("s23", "ok");
String s =
EntityUtils.toString(res.getEntity(), HTTP.UTF_8);
Log.d("s24", "ok");
return s;
}else {
Log.d("s25", "ok");
return "Not Found";
}
}catch(Exception exx){
Log.d("s26", "ok");
Log.d("s27", exx.getMessage());
}
return null;
}
}
这是完整的 Stacktrace: HERE
最佳答案
我个人会推荐使用像 GSON 和 Jackson 这样的东西。链接如下:
GSON: https://sites.google.com/site/gson/gson-user-guide http://www.mkyong.com/java/how-do-convert-java-object-to-from-json-format-gson-api/ http://albertattard.blogspot.co.at/2009/06/practical-example-of-gson.html
jackson : http://jackson.codehaus.org/Tutorial http://www.mkyong.com/java/how-to-convert-java-object-to-from-json-jackson/
现在您必须了解使用这些工具不仅仅是“懒人”。它们是构建良好且快速的映射器。他们将比您在短时间内单独想到的任何算法/方法更快、更容易地完成工作。希望这对您有所帮助!
关于java - 如何使用最佳方式检索 Json 文件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17591303/