Android网络编程之获取网络上的Json

浏览数：24 / 时间：2015年06月11日

Android网络编程之获取网络上的Json


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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：


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：


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：

 

 

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