程序员人生 网站导航

Android网络编程之获取网络上的Json

栏目:综合技术时间:2014-10-10 08:00:00

Android网络编程之获取网络上的Json


请尊重他人的劳动成果,转载请注明出处:Android网络编程之获取网络上的Json 

为要获取网络上的Json所以需要服务器端提供的支持。

一、创建服务器端:

服务器端项目结构:

获取网上的Json服务器端项目结构

服务器端运行效果图:

获取网上的Json服务器端运行效果图

第一步:创建业务所需的JavaBean

 

package com.jph.sj.model; import java.util.Date; /** * 新闻实体类 * @author jph * Date:2014.09.26 */ public class News { private Integer id; private String title; private Date publishDate; public News(Integer id, String title, Date publishDate) { this.id = id; this.title = title; this.publishDate = publishDate; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public Date getPublishDate() { return publishDate; } public void setPublishDate(Date publishDate) { this.publishDate = publishDate; } }

第二步:创建业务逻辑接口和具体实现类

业务接口:

 

package com.jph.sj.service; import java.util.List; import com.jph.sj.model.News; public interface NewsService { /** * 获取最新的资讯 * @return */ public List<News> getLastNews(); }

业务接口的实现类:

 

package com.jph.sj.service.impl; import java.util.ArrayList; import java.util.Date; import java.util.List; import com.jph.sj.model.News; import com.jph.sj.service.NewsService; public class NewsServiceBean implements NewsService { /** * 获取最新的视频资讯 * @return */ public List<News> getLastNews(){ List<News> newes = new ArrayList<News>(); newes.add(new News(1, "李白", new Date(System.currentTimeMillis()))); newes.add(new News(2, "杜甫", new Date(System.currentTimeMillis()+8200))); newes.add(new News(3, "贾宝玉",new Date(System.currentTimeMillis()-6000))); return newes; } }

第三步:创建控制器Servlet

 

package com.jph.sj.servlet; import java.io.IOException; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.jph.sj.model.News; import com.jph.sj.service.NewsService; import com.jph.sj.service.impl.NewsServiceBean; /** * 负责响应客户端的请求:http://xxx/NewsListServlet/NewsListServlet */ public class NewsListServlet extends HttpServlet { private static final long serialVersionUID = 1L; private NewsService newsService = new NewsServiceBean(); protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { List<News> newes = newsService.getLastNews();//获取最新的视频资讯 //[{id:20,title:"xxx",timelength:90},{id:10,title:"xbx",timelength:20}] StringBuilder sbJson = new StringBuilder(); //将list集合封装成Json格式的字符串 sbJson.append('['); for(News news : newes){ sbJson.append('{'); sbJson.append("id:").append(news.getId()).append(","); sbJson.append("title:"").append(news.getTitle()).append("","); sbJson.append("publishDate:").append(news.getPublishDate().getTime()); sbJson.append("},"); } sbJson.deleteCharAt(sbJson.length() - 1);//删除字符串末尾的逗号 sbJson.append(']'); request.setAttribute("json", sbJson.toString()); request.getRequestDispatcher("/WEB-INF/page/jsonnewslist.jsp").forward(request, response); } }

第四步:创建jsonnewslist.jsp页面

 

<%@ page language="java" contentType="text/plain; charset=UTF-8" pageEncoding="UTF-8"%> ${json}

至此服务器端项目已经完成。下面开始创建Android端项目。

二、创建Android端:

Android端项目结构:

获取网上的Json Android端项目结构

第一步:创建业务所需的JavaBean

提示:因为服务器端和Android端项目都是用Java语言实现的,所以一些组件可以共用,JavaBean便是其中之一。此时我们在搭建Android端项目的时候,完全可以将服务器端项目中JavaBean拿来用。

第二步:创建Android端项目的业务逻辑层

核心代码:GetAndParseJson:

 

package com.jph.gj.service; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.ArrayList; import java.util.Date; import java.util.List; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import com.jph.model.News; import android.os.Handler; import android.os.Message; /** * 获取并解析网络上的Json * @author jph * Date:2014.09.26 */ public class GetAndParseJson { private String url="http://10.219.61.117:8080/ServerForJSON/NewsListServlet"; public static final int PARSESUCCWSS=0x2001; private Handler handler; public GetAndParseJson(Handler handler) { // TODO Auto-generated constructor stub this.handler=handler; } /** * 获取网络上的XML */ public void getJsonFromInternet () { new Thread(new Runnable() { @Override public void run() { // TODO Auto-generated method stub try { HttpURLConnection conn=(HttpURLConnection) new URL(url).openConnection(); conn.setConnectTimeout(5000); conn.setRequestMethod("GET"); if (conn.getResponseCode()==200) { InputStream inputStream=conn.getInputStream(); List<News>listNews=parseJson(inputStream); if (listNews.size()>0) { Message msg=new Message(); msg.what=PARSESUCCWSS;//通知UI线程Json解析完成 msg.obj=listNews;//将解析出的数据传递给UI线程 handler.sendMessage(msg); } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } }).start(); } /** * 解析json格式的输入流转换成List * @param inputStream * @return List */ protected List<News> parseJson(InputStream inputStream) { // TODO Auto-generated method stub List<News>listNews=new ArrayList<News>(); byte[]jsonBytes=convertIsToByteArray(inputStream); String json=new String(jsonBytes); try { JSONArray jsonArray=new JSONArray(json); for (int i = 0; i < jsonArray.length(); i++) { JSONObject jObject=jsonArray.getJSONObject(i); int id=jObject.getInt("id"); String title=jObject.getString("title"); long time=jObject.getLong("publishDate"); News news=new News(id, title, new Date(time)); listNews.add(news); } } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } return listNews; } /** * 将输入流转化成ByteArray * @param inputStream * @return ByteArray */ private byte[] convertIsToByteArray(InputStream inputStream) { // TODO Auto-generated method stub ByteArrayOutputStream baos=new ByteArrayOutputStream(); byte buffer[]=new byte[1024]; int length=0; try { while ((length=inputStream.read(buffer))!=-1) { baos.write(buffer, 0, length); } inputStream.close(); baos.flush(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return baos.toByteArray(); } }

第三步:创建Activity

 

package com.jph.gj.activity; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; import com.jph.gj.R; import com.jph.gj.service.GetAndParseJson; import com.jph.model.News; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.app.Activity; import android.widget.ListView; import android.widget.SimpleAdapter; /** * 获取网络上的Json * @author jph * Date:2014.09.26 */ public class MainActivity extends Activity { private List<News>listNews; private ListView list; Handler mHandler=new Handler(){ @Override public void handleMessage(Message msg) { // TODO Auto-generated method stub switch (msg.what) { case GetAndParseJson.PARSESUCCWSS: listNews=(List<News>) msg.obj; initData(); break; } super.handleMessage(msg); } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); list=(ListView)findViewById(R.id.list); GetAndParseJson getAndParseJson=new GetAndParseJson(mHandler); getAndParseJson.getJsonFromInternet(); } /** * 将解析后的xml填充到ListView */ protected void initData() { // TODO Auto-generated method stub List<Map<String, Object>>items=new ArrayList<Map<String,Object>>(); for (News news:listNews) { Map<String, Object>item=new HashMap<String, Object>(); item.put("id", news.getId()); item.put("title", news.getTitle()); item.put("time", convertDate(news.getPublishDate())); items.add(item); } SimpleAdapter adapter=new SimpleAdapter(this, items, R.layout.line, new String[] {"id","title","time"}, new int[]{R.id.tvId,R.id.tvTitle,R.id.tvTime}); list.setAdapter(adapter); } private String convertDate(Date publishDate) { // TODO Auto-generated method stub SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH-mm-ss"); return sdf.format(publishDate); } }

至此Android端项目已经完成了。下面就让我们看一下APP运行效果吧:

Android运行效果图:

 获取网上的Json Android端运行效果图

 

------分隔线----------------------------
------分隔线----------------------------

最新技术推荐