android 访问web应用
用手机访问web应用的demo，整体思路是：
1、通过手机访问web应用，并向服务器发送信息。
2、服务器接收客户端信息。
3、服务器处理数据（解析xml文件）。
4、重组信息，返回给客户端。
一、服务器代码
首先，建立一个web工程：Test1
然后新建一个servlet，用于手机客户端调用。
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class ServletDemo extends HttpServlet {
/**
* Constructor of the object.
*/
public ServletDemo() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy();
}
/**
* 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 {
response.setContentType("text/html");
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");
//获得客户端发送的数据
ServletInputStream is = request.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String requestString = reader.readLine();
//向客户端返回数据
String responseString = processStringRequest(requestString,request);
ServletOutputStream os = response.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os));
writer.write(responseString);
//关闭资源
writer.flush();
writer.close();
reader.close();
os.close();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occure
*/
public void init() throws ServletException {
}
private String processStringRequest(String requestString,HttpServletRequest request){
List list = this.toRead(request.getRealPath("/")+"user.xml");
String response = "";
if(null != list && list.size() > 0){
for(int i = 0 ; i < list.size(); i++){
JavaBean a = (JavaBean)list.get(i);
response += "client say:"+requestString+"server say: this is your info:"+a.getName()+"@"+a.getSex()+"@"+a.getAge();
System.out.println(a.getName());
}
}else{
response = "is wrong!";
}
return response;
}
public List toRead(String filename) {
List alist = new ArrayList();
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document document = db.parse(filename);
NodeList employees = document.getChildNodes();
for (int i = 0; i < employees.getLength(); i++) {
Node employee = employees.item(i);
NodeList employeeInfo = employee.getChildNodes();
for (int j = 0; j < employeeInfo.getLength(); j++) {
Node node = employeeInfo.item(j);
NodeList employeeMeta = node.getChildNodes();
JavaBean bean = new JavaBean();
boolean status = false;
for (int k = 0; k < employeeMeta.getLength(); k++) {
if(employeeMeta.item(k).getNodeName().equals("name")){
bean.setName(employeeMeta.item(k).getTextContent());
}
if(employeeMeta.item(k).getNodeName().equals("age")){
bean.setAge(employeeMeta.item(k).getTextContent());
}
if(employeeMeta.item(k).getNodeName().equals("sex")){
bean.setSex(employeeMeta.item(k).getTextContent());
}
status = true;
}
if(status){
alist.add(bean);
}
}
}
} catch (FileNotFoundException e) {
System.out.println(e.getMessage());
} catch (ParserConfigurationException e) {
System.out.println(e.getMessage());
} catch (SAXException e) {
System.out.println(e.getMessage());
} catch (IOException e) {
System.out.println(e.getMessage());
}
return alist;
}
}
web工程的web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.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>ServletDemo</servlet-name>
<servlet-class>ServletDemo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ServletDemo</servlet-name>
<url-pattern>/servlet/ServletDemo</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
xml文件格式
<?xml version="1.0" encoding="GB2312" standalone="no"?>
<employees>
<employee>
<name>user0</name>
<sex>m</sex>
<age>30</age>
</employee>
</employees>
解析xml文件用到的javabean：
public class JavaBean {
private String name;
private String sex;
private String age;
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
}
二，客户端代码
1、新建Android工程
2、修改main。xml文件
<?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"
>
<EditText
android:layout_height="wrap_content"
android:id="@+id/address"
android:layout_width="fill_parent"
android:text="http://192.168.1.111:8089/Test1/servlet/ServletDemo"
>
</EditText>
<Button
android:id="@+id/ButtonGo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="go!"
>
</Button>
<TextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ffffff"
android:textColor="#000000"
android:id="@+id/pagetext"
/>
</LinearLayout>
3、添加关键代码
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
import android.widget.TextView;
import android.util.Log;
import android.view.View;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
public class ClientDemo extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final TextView tView = (TextView) findViewById(R.id.pagetext);
final Button button = (Button) findViewById(R.id.ButtonGo);
button.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
String response_string = "";
boolean out = true;
boolean in = true;
try {
System.out.println("ty"+tView.getText().toString());
URL url = new URL("http://192.168.1.111:8089/Test1/servlet/ServletDemo");
URLConnection connection = url.openConnection();
connection.setDoInput(in);
connection.setDoOutput(out);
BufferedWriter writer = null;
//向服务器发送数据
if(out){
writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()));
writer.write("I am clent request!!");
writer.flush();
}
//接受服务器返回的数据
BufferedReader reader = null;
if(in){
reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
response_string = reader.readLine();
System.out.println("response: "+response_string);
Log.v("test", response_string);
tView.setText(response_string);
}
if(writer != null){
writer.close();
}
if(reader != null){
reader.close();
}
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.getMessage());
}
}
});
}
}
1、程序启动2、发送请求后
小结。
1、整个demo比较简单，但我们又接触到了新知识，这里面需要注意的是，服务器的ip地址要用实际地址 上篇已经说明了原因。
2、整个步骤比较简单，首先客户端创建连接，然后发送消息，最后接收消息，服务器同理。