Android訪問網路系列之--服務端返回XML或JSON格式資料，Android 進行解析並顯示
阿新 • • 發佈：2019-01-05
例子說明：使用者通過訪問web資源的最新電影資訊，伺服器端生成XML或JSON格式資料，返回Android客戶端進行顯示。
此案例開發需要兩個方面 WEB開發和android開發.
一.web開發相對比較簡單，只是模擬一下
相關程式碼如下：
1.實體Bean
package ygc.yxb.domain; /** * 電影資訊實體Bean * @author YXB * */ public class News { private Integer id; //id private String title; //電影名稱 privateInteger timelenght; //時長 public News() { } public News(Integer id, String title, Integer timelenght) { this.id = id; this.title = title; this.timelenght = timelenght; } public Integer getId() { return id; } publicvoid setId(Integer id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public Integer getTimelenght() { return timelenght; } public void setTimelenght(Integer timelenght) {this.timelenght = timelenght; } }
2.業務邏輯
package ygc.yxb.service.impl; import java.util.ArrayList; import java.util.List; import ygc.yxb.domain.News; import ygc.yxb.service.VideoNewsService; public class VideoNewsServiceImpl implements VideoNewsService { /** * 獲取電影資訊的業務方法 */ public List<News> getLastNews(){ List<News> newses = new ArrayList<News>(); newses.add(new News(32, "大話西遊", 90)); newses.add(new News(12, "軒轅劍", 40)); newses.add(new News(56, "愛情公寓", 30)); return newses; } }
3.Servlet
package ygc.yxb.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 ygc.yxb.domain.News; import ygc.yxb.service.VideoNewsService; import ygc.yxb.service.impl.VideoNewsServiceImpl; /** * 用最原始的web開發servlet請求伺服器，並返回客戶端資料 */ public class ListServlet extends HttpServlet { private static final long serialVersionUID = 1L; private VideoNewsService service = new VideoNewsServiceImpl(); 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> videos = service.getLastNews(); String format=request.getParameter("format"); //如果使用者請求的是這個路徑，則返回JSON格式的資料.http://192.168.1.113:8080/videonews/ListServlet?format=json if("json".equals(format)){ //[{id:56,title:"xxxx",timelength:90}] //組拼一個JSON格式的物件 StringBuilder builder = new StringBuilder(); builder.append('['); for (News news : videos) { builder.append('{'); builder.append("id:").append(news.getId()).append(','); builder.append("title:\"").append(news.getTitle()).append("\","); builder.append("timelength:").append(news.getTimelenght()); builder.append("},"); } builder.deleteCharAt(builder.length()-1); builder.append(']'); request.setAttribute("json", builder.toString()); request.getRequestDispatcher("/WEB-INF/page/jsonvideonews.jsp").forward(request, response); //如果使用者請求的是這個路徑，則返回XML格式的資料.http://192.168.1.113:8080/videonews/ListServlet }else{ request.setAttribute("videos", videos); request.getRequestDispatcher("/WEB-INF/page/videonews.jsp").forward(request, response); } } }
4.jsp頁面
4.1.jsonvideonews.jsp
<%@ page language="java" contentType="text/plain; charset=UTF-8" pageEncoding="UTF-8"%>${json}
4.2.videonews.jsp XML資料
<%@ page language="java" contentType="text/xml; charset=UTF-8" pageEncoding="UTF-8"%><%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><?xml version="1.0" encoding="UTF-8"?>
<videonews>
<c:forEach items="${videos}" var="video">
<news id ="${video.id }">
<title>${video.title }</title>
<timelength>${video.timelenght}</timelength>
</news>
</c:forEach>
</videonews>
到此為止web開發完畢，現在Android開發相關程式碼
1.實體Bean
package ygc.yxb.domain; public class News { private Integer id; private String title; private Integer timelenght; public News() { } public News(Integer id, String title, Integer timelenght) { this.id = id; this.title = title; this.timelenght = timelenght; } 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 getTimelenght() { return timelenght; } public void setTimelenght(Integer timelenght) { this.timelenght = timelenght; } }
2.業務邏輯
package ygc.yxb.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 ygc.yxb.domain.News; import ygc.yxb.utils.StreamTool; public class VideoNewsService { /** * 獲取最新的視訊資訊接受伺服器端XML格式的資料 * @return * @throws Exception */ public static List<News> getLastNews() throws Exception{ String path="http://192.168.1.113:8080/videonews/ListServlet"; URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setConnectTimeout(5000); conn.setRequestMethod("GET"); if(conn.getResponseCode()==200){ InputStream inStream=conn.getInputStream(); return parseXML(inStream); } return null; } /** * 獲取最新的視訊資訊 接受伺服器端JSON格式的資料 * @return * @throws Exception */ public static List<News> getJSONLastNews() throws Exception{ String path="http://192.168.1.113:8080/videonews/ListServlet?format=json"; URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setConnectTimeout(5000); conn.setRequestMethod("GET"); if(conn.getResponseCode()==200){ InputStream inStream=conn.getInputStream(); return parseJSON(inStream); } return null; } /** * 解析JSON資料 * @param inStream * @return */ private static List<News> parseJSON(InputStream inStream) throws Exception { List<News> newses = new ArrayList<News>(); byte[] data =StreamTool.read(inStream); //將位元組陣列轉換成字串 String json= new String(data); //將json物件轉換成json的陣列物件 JSONArray array = new JSONArray(json); 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; } /** * 解析伺服器返回的XML資料 * @param inStream * @return */ private static List<News> parseXML(InputStream inStream) throws Exception{ List<News> newses = new ArrayList<News>(); News news = null; //用Pull解析器解析XML檔案 XmlPullParser parser= Xml.newPullParser(); parser.setInput(inStream, "UTF-8"); //得到開始文件XML事件 int event = parser.getEventType(); //不等於結束事件，迴圈讀取XML檔案並封裝成物件 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.setTimelenght(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; } }
3.Activity
package ygc.yxb.news; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import ygc.yxb.domain.News; import ygc.yxb.service.VideoNewsService; import android.app.Activity; import android.os.Bundle; import android.widget.ListView; import android.widget.SimpleAdapter; public class MainActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ListView listView=(ListView)this.findViewById(R.id.listView); try { List<News> videos=VideoNewsService.getJSONLastNews(); 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.getTimelenght()+getResources().getString(R.string.min)); data.add(item); } //用SimpleAdapter 繫結ListView控制元件 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) { e.printStackTrace(); } } }
4讀取資料流工具類:
package ygc.yxb.utils; import java.io.ByteArrayOutputStream; import java.io.InputStream; public class StreamTool { /** * 讀取流中的資料 * @param inStream * @return * @throws Exception */ public static byte[] read(InputStream inStream) throws Exception { ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; //如果位元組流中的資料不等於-1，就說明一直有，然後迴圈讀出 while( (len=inStream.read(buffer)) !=-1){ //將讀出的資料放入記憶體中 outputStream.write(buffer); } inStream.close(); return outputStream.toByteArray(); } }
這裡android 開發完畢，而顯示的控制元件是ListView 最後在清單檔案中，配置訪問網路的許可權即可。
執行效果如下：
