Android网络编程之获取网络上的Json数据实例

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：