android HTTP 通信, XML 解析, 通过 Hander 实现异步消息处理 (1)
2011-05-12 12:29
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android HTTP 通信, XML 解析, 通过 Hander 实现异步消息处理 (1)
2010-02-03 10:55
2010-02-03 10:55
介绍 在 Android 中与服务端做 HTTP 通信,解析 XML,通过 Handler 实现异步消息处理 HTTP 通信 - 与服务端做 HTTP 通信,分别以 GET 方式和 POST 方式做演示 XML 解析 - 可以用两种方式解析 XML,分别是 DOM 方式和 SAX 方式 异步消息处理 - 通过 Handler 实现异步消息处理,以一个自定义的异步下载类来说明 Handler 的用法 1、HTTP 通信和 XML 解析的 Demo MySAXHandler.java 代码 package com.webabcd.communication; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; // 继承 DefaultHandler 以实现指定 XML 的 SAX 解析器 // DOM - W3C 标准,需要把 xml 数据全部加载完成后才能对其做解析,可对树做任意遍历 // SAX - 流式解析,通过事件模型解析 xml,只能顺序解析 public class MySAXHandler extends DefaultHandler { private boolean mIsTitleTag = false; private boolean mIsSalaryTag = false; private boolean mIsBirthTag = false; private String mResult = ""; // 打开 xml 文档的回调函数 @Override public void startDocument() throws SAXException { // TODO Auto-generated method stub super.startDocument(); } // 关闭 xml 文档的回调函数 @Override public void endDocument() throws SAXException { // TODO Auto-generated method stub super.endDocument(); } // 一发现元素开始标记就回调此函数 @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { if (localName == "title") mIsTitleTag = true; else if (localName == "salary") mIsSalaryTag = true; else if (localName == "dateOfBirth") mIsBirthTag = true; else if (localName == "employee") mResult += "/nname:" + attributes.getValue("name"); } // 一发现元素结束标记就回调此函数 @Override public void endElement(String uri, String localName, String qName) throws SAXException { if (localName == "title") mIsTitleTag = false; else if (localName == "salary") mIsSalaryTag = false; else if (localName == "dateOfBirth") mIsBirthTag = false; } // 一发现元素值或属性值就回调此函数 @Override public void characters(char[] ch, int start, int length) throws SAXException { if (mIsTitleTag) mResult += new String(ch, start, length); else if (mIsSalaryTag) mResult += " salary:" + new String(ch, start, length); else if (mIsBirthTag) mResult += " dateOfBirth:" + new String(ch, start, length); } public String getResult(){ return mResult; } } Main.java 代码 package com.webabcd.communication; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.util.ArrayList; import java.util.HashMap; import java.util.Map; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.protocol.HTTP; import org.apache.http.util.ByteArrayBuffer; import org.apache.http.util.EncodingUtils; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import org.xml.sax.InputSource; import org.xml.sax.XMLReader; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.TextView; public class Main extends Activity { private TextView textView; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); textView = (TextView) this.findViewById(R.id.textView); Button btn1 = (Button) this.findViewById(R.id.btn1); btn1.setText("http get demo"); btn1.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { httpGetDemo(); } }); Button btn2 = (Button) this.findViewById(R.id.btn2); btn2.setText("http post demo"); btn2.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { httpPostDemo(); } }); Button btn3 = (Button) this.findViewById(R.id.btn3); // DOM - Document Object Model btn3.setText("DOM 解析 XML"); btn3.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { DOMDemo(); } }); Button btn4 = (Button) this.findViewById(R.id.btn4); // SAX - Simple API for XML btn4.setText("SAX 解析 XML"); btn4.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { SAXDemo(); } }); } // Android 调用 http 协议的 get 方法 // 本例:以 http 协议的 get 方法获取远程页面响应的内容 private void httpGetDemo(){ try { // 模拟器测试时,请使用外网地址 URL url = new URL("http://xxx.xxx.xxx"); URLConnection con = url.openConnection(); String result = "http status code: " + ((HttpURLConnection)con).getResponseCode() + "/n"; // HttpURLConnection.HTTP_OK InputStream is = con.getInputStream(); BufferedInputStream bis = new BufferedInputStream(is); ByteArrayBuffer bab = new ByteArrayBuffer(32); int current = 0; while ( (current = bis.read()) != -1 ){ bab.append((byte)current); } result += EncodingUtils.getString(bab.toByteArray(), HTTP.UTF_8); bis.close(); is.close(); textView.setText(result); } catch (Exception e) { textView.setText(e.toString()); } } // Android 调用 http 协议的 post 方法 // 本例:以 http 协议的 post 方法向远程页面传递参数,并获取其响应的内容 private void httpPostDemo(){ try { // 模拟器测试时,请使用外网地址 String url = "http://5billion.com.cn/post.php"; Map<String, String> data = new HashMap<String, String>(); data.put("name", "webabcd"); data.put("salary", "100"); DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); ArrayList<BasicNameValuePair> postData = new ArrayList<BasicNameValuePair>(); for (Map.Entry<String, String> m : data.entrySet()) { postData.add(new BasicNameValuePair(m.getKey(), m.getValue())); } UrlEncodedFormEntity entity = new UrlEncodedFormEntity(postData, HTTP.UTF_8); httpPost.setEntity(entity); HttpResponse response = httpClient.execute(httpPost); String result = "http status code: " + response.getStatusLine().getStatusCode() + "/n"; // HttpURLConnection.HTTP_OK HttpEntity httpEntity = response.getEntity(); InputStream is = httpEntity.getContent(); result += convertStreamToString(is); textView.setText(result); } catch (Exception e) { textView.setText(e.toString()); } } // 以 DOM 方式解析 XML(xml 数据详见 res/raw/employee.xml) private void DOMDemo(){ try { DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder docBuilder = docFactory.newDocumentBuilder(); Document doc = docBuilder.parse(this.getResources().openRawResource(R.raw.employee)); Element rootElement = doc.getDocumentElement(); NodeList employeeNodeList = rootElement.getElementsByTagName("employee"); textView.setText("DOMDemo" + "/n"); String title = rootElement.getElementsByTagName("title").item(0).getFirstChild().getNodeValue(); textView.append(title); for (int i=0; i<employeeNodeList.getLength(); i++){ Element employeeElement = ((Element)employeeNodeList.item(i)); String name = employeeElement.getAttribute("name"); String salary = employeeElement.getElementsByTagName("salary").item(0).getFirstChild().getNodeValue(); String dateOfBirth = employeeElement.getElementsByTagName("dateOfBirth").item(0).getFirstChild().getNodeValue(); textView.append("/nname: "+name+" salary: "+salary+" dateOfBirth: " + dateOfBirth); } } catch (Exception e) { textView.setText(e.toString()); } } // 以 SAX 方式解析 XML(xml 数据详见 res/raw/employee.xml) // SAX 解析器的实现详见 MySAXHandler.java private void SAXDemo(){ try { SAXParserFactory saxFactory = SAXParserFactory.newInstance(); SAXParser parser = saxFactory.newSAXParser(); XMLReader reader = parser.getXMLReader(); MySAXHandler handler = new MySAXHandler(); reader.setContentHandler(handler); reader.parse(new InputSource(this.getResources().openRawResource(R.raw.employee))); String result = handler.getResult(); textView.setText("SAXDemo" + "/n"); textView.append(result); } catch (Exception e) { textView.setText(e.toString()); } } // 辅助方法,用于把流转换为字符串 private String convertStreamToString(InputStream is) { BufferedReader reader = new BufferedReader(new InputStreamReader(is)); StringBuilder sb = new StringBuilder(); String line = null; try { while ((line = reader.readLine()) != null) { sb.append(line + "/n"); } } catch (IOException e) { e.printStackTrace(); } finally { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } return sb.toString(); |
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