android解析服务器传来的xml文件和json文件（一）

      用一个简单的例子来解析服务器端传来的xml文件，首先要在服务器端建立一个网站。在网站中建立了一个servlet的类名字叫CityAction。它用来响应android端用post方法传来的请求。再建立一个CityDataSource类，里面的getCityList()方法返回给CityAction一个城市名的list，然后再CityAction封装成一个json字符串，传递给android客户端。json的jar包我会在前面的资源中给出来过，大家可以免费下载。代码如下：

package com.city.action;import java.io.IOException;import java.io.PrintWriter;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import net.sf.json.JSONSerializer;public class CityAction extends HttpServlet {/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. *  * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. *  * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html;charset=utf-8");request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");PrintWriter writer=response.getWriter();String type=request.getParameter("type");if(type.equals("json")){List<String> list=CityDataSource.getCityList();Map<String, List<String>> map=new HashMap<String, List<String>>();map.put("citys", list);String jsonString=JSONSerializer.toJSON(map).toString();writer.println(jsonString);}else if(type.equals("xml")){String jsonString=CityDataSource.getCityListXML();writer.println(jsonString);}writer.flush();writer.close();}}

jsonString 就是要传递给客户端的字符串。

package com.city.action;import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import java.io.Reader;import java.nio.charset.Charset;import java.util.ArrayList;import java.util.List;public class CityDataSource {public static List<String> getCityList(){List<String> list=new ArrayList<>();list.add("北京");list.add("上海");list.add("南京");list.add("成都");list.add("天津");return list;}public static  String getCityListXML(){//List<String> list=new ArrayList<>();//把文件读到字节流中InputStream inputStream=CityDataSource.class.getClassLoader().getResourceAsStream("com/city/action/citys.xml");//在把字节流通过缓冲流读到字符串中Reader reader=new InputStreamReader(inputStream,Charset.forName("utf-8"));BufferedReader bufferedReader=new BufferedReader(reader);String value="";StringBuilder builder=new StringBuilder();try {while((value=bufferedReader.readLine())!=null){builder.append(value);}//System.out.println(builder.toString());return builder.toString();} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}finally{if(bufferedReader!=null){try {bufferedReader.close();} catch (Exception e2) {// TODO: handle exceptione2.printStackTrace();}}}return null;}}

getcitylistxml是将自己定义好的一个xml文件读到inputStream中然后通过缓冲流读成xml字符串，再将字符串传递给客户端来解析就ok了。

我的xml文件如下：

<?xml version="1.0" encoding="UTF-8"?><citys><city><name>北京</name></city><city><name>上海</name></city><city><name>成都</name></city><city><name>河南</name></city><city><name>西藏</name></city></citys>

服务器端就完成了，在访问的时候只需

http://localhost:8080/xmljson/servlet/CityAction?type=json

http://localhost:8080/xmljson/servlet/CityAction?type=xml

通过type就可以知道你需要哪种格式的返回文件。
ok服务器端就是这样。马上上客户端的代码。请见下一篇：