我的Android进阶之旅------>Android获取服务器上格式为JSON和XML两种格式的信息的小程序

 

 

首先写一个应用服务器端的jsp程序，用jsp和servlet简单实现，如下图所示

 

 

package cn.roco.domain;public class News {private Integer id;private String title;private Integer timelength;public News() {}public News(Integer id, String title, Integer timelength) {this.id = id;this.title = title;this.timelength = timelength;}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 Integer getTimelength() {return timelength;}public void setTimelength(Integer timelength) {this.timelength = timelength;}}

 

 

package cn.roco.service;import java.util.List;import cn.roco.domain.News;public interface VideoNewsService {/** * 获取最新视频资讯 * @return */public List<News> getLastNews();}

 

package cn.roco.service.impl;import java.util.ArrayList;import java.util.List;import cn.roco.domain.News;import cn.roco.service.VideoNewsService;public class VideoNewsServiceBean implements VideoNewsService{/** * 模拟从服务器中获取数据  返回 */public List<News> getLastNews(){List<News> newses=new ArrayList<News>();for (int i = 1; i < 30; i++) {newses.add(new News(i,"Xili"+i,i+90));}return newses;}}

 
 

package cn.roco.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 cn.roco.domain.News;import cn.roco.service.VideoNewsService;import cn.roco.service.impl.VideoNewsServiceBean;public class ListServlet extends HttpServlet {private VideoNewsService newsService=new VideoNewsServiceBean();protected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {List<News> videos=newsService.getLastNews();String format=req.getParameter("format");//返回JSON格式if ("json".equals(format)) {StringBuilder builder=new StringBuilder();builder.append('[');for (News news : videos) {builder.append('{');builder.append("id:").append(news.getId()).append(',');//转义 ""双引号builder.append("title:\"").append(news.getTitle()).append("\",");builder.append("timelength:").append(news.getTimelength());builder.append("},");}builder.deleteCharAt(builder.length()-1);//去掉最后的','builder.append(']');req.setAttribute("json", builder.toString());req.getRequestDispatcher("/WEB-INF/page/jsonvideonews.jsp").forward(req, resp);}else{//返回XML格式req.setAttribute("videos", videos);req.getRequestDispatcher("/WEB-INF/page/videonews.jsp").forward(req, resp);}}protected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {doGet(req, resp);}}

 

 如果要返回XML文件  就forward到videonews.jsp页面

<%@ page language="java" contentType="text/xml; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><?xml version="1.0" encoding="UTF-8"?><videonews> <c:forEach items="${videos}" var="video"><news id="${video.id}"><title>${video.title}</title><timelength>${video.timelength}</timelength> </news></c:forEach> </videonews>

如果要返回XML文件  就forward到videonews.jsp页面 如果要返回JSON文件 就forward到jsonvideonews.jsp页面

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

 

web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  <servlet>    <description>This is the description of my J2EE component</description>    <display-name>This is the display name of my J2EE component</display-name>    <servlet-name>ListServlet</servlet-name>    <servlet-class>cn.roco.servlet.ListServlet</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>ListServlet</servlet-name>    <url-pattern>/ListServlet</url-pattern>  </servlet-mapping>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

 

 

服务器端写好之后,就开始写Android应用

架构如下图所示：

 

package cn.roco.news.domain;public class News {private Integer id;private String title;private Integer timelength;public News() {}public News(Integer id, String title, Integer timelength) {this.id = id;this.title = title;this.timelength = timelength;}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 Integer getTimelength() {return timelength;}public void setTimelength(Integer timelength) {this.timelength = timelength;}}

 

package cn.roco.utils;import java.io.ByteArrayOutputStream;import java.io.InputStream;public class StremTools {/** * 读取输入流中的数据 * @param inputStream  输入流 * @return   二进制的流数据 * @throws Exception */public static byte[] read(InputStream inputStream) throws Exception {ByteArrayOutputStream outputStream=new ByteArrayOutputStream();byte[] buffer=new byte[1024];int length=0;while((length=inputStream.read(buffer))!=-1){outputStream.write(buffer,0,length);}inputStream.close();return outputStream.toByteArray();}}

 

package cn.roco.news.service;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 org.xmlpull.v1.XmlPullParser;import android.util.Xml;import cn.roco.news.domain.News;import cn.roco.utils.StremTools;public class VideoNewsService {/** * 获取最新的视频资讯 * 采用JSON格式 * @param path * @return * @throws Exception */public static List<News> getJSONLastNews(String path) throws Exception {URL url = new URL(path);HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 基于HTTP协议连接对象connection.setConnectTimeout(5000);connection.setRequestMethod("GET");if (connection.getResponseCode() == 200) {InputStream inputStream = connection.getInputStream();return parseJSON(inputStream);}else{throw new RuntimeException("服务器响应失败");}}/** * 解析服务器返回的JSON数据 *  * @param inputStream * @return * @throws Exception  */private static List<News> parseJSON(InputStream inputStream) throws Exception {List<News> newses=new ArrayList<News>();byte[] data=StremTools.read(inputStream);String jsonData=new String(data,"UTF-8");JSONArray array=new JSONArray(jsonData); for (int i = 0; i < array.length(); i++) { JSONObject jsonObject= array.getJSONObject(i); News news=new News( jsonObject.getInt("id"), jsonObject.getString("title"),jsonObject.getInt("timelength")); newses.add(news);}return newses;}/** * 获取最新的视频资讯 * 采用XML格式 * @param path * @return * @throws Exception */public static List<News> getLastNews(String path) throws Exception {URL url = new URL(path);HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 基于HTTP协议连接对象connection.setConnectTimeout(5000);connection.setRequestMethod("GET");if (connection.getResponseCode() == 200) {InputStream inputStream = connection.getInputStream();return parseXML(inputStream);}return null;}/** * 解析服务器返回的XML数据 *  * @param inputStream * @return */private static List<News> parseXML(InputStream inputStream) throws Exception {List<News> newses = new ArrayList<News>();News news = null;XmlPullParser parser = Xml.newPullParser();parser.setInput(inputStream, "UTF-8");int event = parser.getEventType();while (event != XmlPullParser.END_DOCUMENT) {switch (event) {case XmlPullParser.START_TAG:if ("news".equals(parser.getName())) {int id = new Integer(parser.getAttributeValue(0));news = new News();news.setId(id);} else if ("title".equals(parser.getName())) {news.setTitle(parser.nextText());} else if ("timelength".equals(parser.getName())) {news.setTimelength(new Integer(parser.nextText()));}break;case XmlPullParser.END_TAG:if ("news".equals(parser.getName())) {newses.add(news);news = null;}break;}event = parser.next();}return newses;}}

package cn.roco.news;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import cn.roco.news.domain.News;import cn.roco.news.service.VideoNewsService;import android.app.Activity;import android.os.Bundle;import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.Toast;public class MainActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);ListView listView = (ListView) findViewById(R.id.listView);try {//采用XML格式//String xmlPath="http://192.168.15.58:8080/Hello/ListServlet";//List<News> videos = VideoNewsService.getLastNews();//采用JSON格式String jsonPath="http://192.168.15.58:8080/Hello/ListServlet?format=json";List<News> videos = VideoNewsService.getJSONLastNews(jsonPath);List<HashMap<String, Object>> data = new ArrayList<HashMap<String, Object>>();for (News news : videos) {HashMap<String, Object> item = new HashMap<String, Object>();item.put("id", news.getId());item.put("title", news.getTitle());item.put("timelength",getResources().getString(R.string.timelength)+ news.getTimelength()+ getResources().getString(R.string.min));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) {Toast.makeText(getApplicationContext(), "有错", 1);e.printStackTrace();}}}

 item.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="horizontal" android:layout_width="fill_parent"android:layout_height="fill_parent"><TextView android:id="@+id/title" android:layout_width="200dp"android:layout_height="wrap_content"/><TextView android:id="@+id/timelength" android:layout_width="fill_parent"android:layout_height="wrap_content"/></LinearLayout>

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical" android:layout_width="fill_parent"android:layout_height="fill_parent"><LinearLayout android:orientation="horizontal"android:layout_width="wrap_content" android:layout_height="wrap_content"><TextView android:text="@string/title" android:layout_width="200dp"android:layout_height="wrap_content" /><TextView android:text="@string/details" android:layout_width="wrap_content"android:layout_height="wrap_content" /></LinearLayout><ListView android:layout_width="fill_parent"android:layout_height="wrap_content" android:id="@+id/listView" /></LinearLayout>

 

string.xml

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello World, MainActivity!</string>    <string name="app_name">视频资讯</string>    <string name="timelength">时长：</string>    <string name="min">分钟</string>    <string name="title">标题</string>    <string name="details">详情</string></resources>

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="cn.roco.news"      android:versionCode="1"      android:versionName="1.0">    <uses-sdk android:minSdkVersion="8" />   <!-- 访问Internet权限 --><uses-permission android:name="android.permission.INTERNET"/>    <application android:icon="@drawable/icon" android:label="@string/app_name">        <activity android:name=".MainActivity"                  android:label="@string/app_name">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

 

运行效果如图所示：
 

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  作者：欧阳鹏  欢迎转载，与人分享是进步的源泉！

  转载请保留原文地址：http://blog.csdn.net/ouyang_peng

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