javaapplet例子.doc

例子1：运行，编译，网页中嵌入的例子import java.applet.*;import java.awt.*;public class Example12_1 extends Applet Button button1,button2; int sum; public void init() setBackground(Color.gray);button1=new Button(yes); button2=new Button(No); add(button1); add(button2); public void start() sum=0; for(int i=1;i=100;i+) sum=sum+i; public void stop() public void paint(Graphics g) g.setColor(Color.blue); g.drawString(程序设计方法,20,60); g.setColor(Color.red); g.drawString(sum=+sum,20,100); 例子2：网页向JavaApplet传值import java.awt.*;import java.applet.*;public class Example12_2 extends Applet int x=0,y=0; public void init() String s1=getParameter(girl);/从html得到girl的值。 String s2=getParameter(boy);/从html得到boy的值。 x=Integer.parseInt(s1); y=Integer.parseInt(s2); public void paint(Graphics g) g.drawString(x=+x+,+y=+y,90,120); Boy.html 例子3：JavaApplet中使用URLimport java.applet.*;import java.awt.*;import java.awt.event.*;import .*;public class Boy extends Applet implements ActionListener Button button; URL url; TextField text; public void init() text=new TextField(18); button=new Button(“确定”); add(new Label(“输入网址:”); add(text); add(button); button.addActionListener(this); public void actionPerformed(ActionEvent e) if(e.getSource()=button) try url=new URL(text.getText().trim(); getAppletContext().showDocument(url); catch(MalformedURLException g) text.setText(“不正确的URL:+url); 例子4：建立新线程import java.applet.*;import java.awt.*;import .*;import java.io.*;public class ReadFile extends Applet TextArea text; URL url; public void init() text=new TextArea(12,40); add(text); public void start() try url=new URL(getCodeBase(),hello.txt); InputStream in=url.openStream(); /url返回输入流 int n=-1; byte b=new byte100; while(n=in.read(b)!=-1) String str=new String(b,0,n); text.append(str); catch(Exception ee) 例子5：使用套接字import java.applet.*;import java.awt.*;import java.awt.event.*;public class CircleAndRect extends Applet implements Runnable Thread left ,right; Graphics mypen; int x,y; public void init() left=new Thread(this); right=new Thread(this); x=10;y=10; mypen=getGraphics(); public void start() try left.start(); right.start(); catch(Exception e) public void run() while(true) if(Thread.currentThread()=left) x=x+1; if(x240) x=10; mypen.setColor(Color.blue); mypen.clearRect(10,10,300,40); mypen.drawRect(10+x,10,40,40); try left.sleep(60); catch(InterruptedException e) else if(Thread.currentThread()=right) y=y+1; if(y240) y=10; mypen.setColor(Color.red); mypen.clearRect(10,90,300,40); mypen.drawOval(10+y,90,40,40); try right.sleep(60); catch(InterruptedException e) 例子6（1）客户端import .*;import java.io.*;import java.awt.*;import java.applet.*;public class Client extends Applet implements Runnable TextField text; Socket socket=null; ObjectInputStream in=null; ObjectOutputStream out=null; Thread thread; public void init() thread=new Thread(this); public void start() try thread.start(); socket=new Socket(this.getCodeBase().getHost(), 4331); in=new ObjectInputStream(socket.getInputStream(); out=new ObjectOutputStream(socket.getOutputStream(); catch(Exception e) public void run() String s=null; while(true) try text=(TextField)in.readObject(); add(text); validate(); return; catch(Exception e) （2）服务器端import java.io.*;import .*;import java.util.*;import java.awt.*;public class Server public static void main(String args) ServerSocket server=null; Server_thread thread; Socket you=null; while(true) try server=new ServerSocket(4331); catch(IOException e1) System.out.println(正在监听); try you=server.accept(); catch (IOException e) if(you!=null) new Server_thread(you).start(); class Server_thread extends Thread Socket socket; ObjectOutputStream out=null; ObjectInputStream in=null; String s=null; Server_thread(Socket t) socket=t; try out=new ObjectOutputStream(socket.get