clientapp.java

用Eclipse实现的J2me程序,实现了页面的跳转等

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.io.*;

public class ClientApp extends MIDlet implements CommandListener 
{
	Display display; 
    TextField tf1,tf2; 
    String tf1Str,tf2Str;
    Form inputForm,returnForm;
    Command cmdSend,cmdBack;
    final static String defaultURL = "http://localhost:8080/ForCommunicateWithMIDlet/servlet";

    public ClientApp(){
    	display = Display.getDisplay(this);
    	tf1 = new TextField("input first param:","肖云鹏",20,TextField.ANY);
    	tf2 = new TextField("input second param:","张三",20,TextField.ANY);
    	cmdSend = new Command("Send",Command.SCREEN,1);
    	cmdBack = new Command("Back",Command.SCREEN,1);
    	inputForm = new Form("pls input the param:");
    	inputForm.append(tf1); 
    	inputForm.append(tf2);
    	inputForm.addCommand(cmdSend);
    	inputForm.setCommandListener(this);    	
    }

    public void startApp() throws MIDletStateChangeException{
    	display.setCurrent(inputForm);
    }

    public void invokeServlet(String url) throws IOException {
    	HttpConnection hc = null; 
        DataOutputStream dos = null;
        DataInputStream dis = null;
        try{
        	hc = (HttpConnection)Connector.open(url,Connector.READ_WRITE);
            //设置请求属性
            hc.setRequestMethod(HttpConnection.POST);
            //设置为POST请求方式,默认的请求方式是GET
            hc.setRequestProperty("IF-Modified-Since","15 Oct 2003 08:47:14 GMT");
            hc.setRequestProperty("User-Agent","Profile/MIDP-1.0 Configuration/CLDC-1.0");
            hc.setRequestProperty("Content-Language","en-CA");
            hc.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
            hc.setRequestProperty("Connection","Keep-Alive");
            //Connection头可以控制MIDlet和Web服务器之间保持"keep alive"特色。
            //"keep alive"特色是指在MIDlet和Web服务器间始终使用同一个HTTP连接来多次传递数据
            //（在通常情况下，HTTP是无连接的协议，每次数据传输完毕后都将断开连接，
            //而下次传递数据之前将重新建立连接） 
            //发送请求参数到servlet
            dos = hc.openDataOutputStream();
            dos.writeUTF(tf1Str); 
            dos.writeUTF(tf2Str);
            //用于发送请求参数给servlet
            System.out.println("手机传递给servlet的第一个参数为:"+ tf1Str);
            //主要起调试的作用，调试的结果将显示在WTK的控制台中
            System.out.println("手机传递给servlet的第一个参数为:"+ tf2Str);

            dos.flush();
            dos.close();

            //接收servlet响应数据
            dis = new DataInputStream(hc.openInputStream());
            String return1Str = dis.readUTF();
            String return2Str = dis.readUTF();
            System.out.println("手机接收到servlet端传来的第一个参数为:" + return1Str);
            //主要起调试的作用，调试的结果将显示在WTK的控制台中
            System.out.println("手机接收到servlet端传来的第二个参数为:" + return2Str);
            returnForm = new Form("返回的结果");
            returnForm.append(return1Str);
            returnForm.append("\n");
            //将返回的结果append到resultForm中
            returnForm.append(return2Str);
            returnForm.addCommand(cmdBack);
            returnForm.setCommandListener(this);
            }finally{
            	if (dis != null) {
            		dis.close();
            		}
            	if (dos != null) {
            		dos.close();
            		}
            	if (hc != null) {
            		hc.close();
            		}
            	}
            display.setCurrent(returnForm);
            }

    public void pauseApp(){}
    
    public void destroyApp(boolean unconditional){}
    
    public void commandAction(Command c,Displayable d){
    	if(c == cmdBack){
    		display.setCurrent(inputForm);
    		}
    	if(c == cmdSend){
    		tf1Str = tf1.getString();
    		tf2Str = tf2.getString();
    		try{
    			invokeServlet(defaultURL);
    			}catch(Exception e){
    				System.out.println(e.getMessage());
    				}
    			}
    	}
    }