java 发送 接受 xml请求

二、客户端代码

通过Http Post Xml传递数据，客户端一般是通过URL建立到服务端的连接，向服务端发送xml数据，然后获取服务端的响应并进行解析：

String xmlString = "<?xml version='1.0' encoding='gb2312'?>"
                       + "<Req>"
                       + "<EventContentReq>"
                       + "<EventID>101</EventID >"
                       + "</EventContentReq>"
                       + "</Req>";

byte[] xmlData = xmlString.getBytes();

String urlStr = "http://124.128.62.164:7001/FetchTaskDataServlet";

DataInputStream input = null;

java.io.ByteArrayOutputStream out = null;

try{

       //获得到位置服务的链接

         URL url = new URL(urlStr);

         URLConnection urlCon = url.openConnection();

         urlCon.setDoOutput(true);

         urlCon.setDoInput(true);

         urlCon.setUseCaches(false);

       //将xml数据发送到位置服务

         urlCon.setRequestProperty("Content-Type", "text/xml");

         urlCon.setRequestProperty("Content-length",String.valueOf(xmlData.length));

         DataOutputStream printout = new DataOutputStream(urlCon.getOutputStream());

         printout.write(xmlData);

         printout.flush();

         printout.close();

         input = new DataInputStream(urlCon.getInputStream());

       byte[] rResult;

         out = new java.io.ByteArrayOutputStream();

       byte[] bufferByte = newbyte[256];

       int l = -1;

       int downloadSize = 0;

       while ((l = input.read(bufferByte)) > -1) {

             downloadSize += l;

             out.write(bufferByte, 0, l);

             out.flush();

         }

         rResult = out.toByteArray();

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse(new ByteArrayInputStream(rResult));

         String TaskAddr = d.getElementsByTagName("TaskAddr").item(0).getFirstChild().getNodeValue();

         System.out.println("TaskAddr:"+TaskAddr);

}

catch(Exception e){

         e.printStackTrace();

}

finally {

       try {

                out.close();

                input.close();

         }

       catch (Exception ex) {

         }

}
三、服务端代码
服务端一般首先获取客户端发来的xml数据，进行解析，并将响应返回给客户端：
try{

//解析对方发来的xml数据，获得EventID节点的值

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse(request.getInputStream());

         String evtid = d.getElementsByTagName("EventID").item(0).getFirstChild().getNodeValue();

//                     System.out.println("evtid" + evtid);

       //根据evtid查找任务，生成xml字符串

         UfgovDBUtil dbUtil = new UfgovDBUtil();

         String xmlString = dbUtil.fetchTaskData(evtid);

//                     System.out.println("returned xmlString:" + xmlString);

       //把xml字符串写入响应

       byte[] xmlData = xmlString.getBytes();

         response.setContentType("text/xml");

         response.setContentLength(xmlData.length);

         ServletOutputStream os = response.getOutputStream();

         os.write(xmlData);

         os.flush();

         os.close();

}

catch(Exception e){

         e.printStackTrace();

}