例代码-12

第十二章JavaApplet基础



例子1

importjava.applet.;

importjava.awt.;

publicclassExample12_1extendsApplet

{Buttonbutton1,button2;

intsum;

publicvoidinit()

{setBackground(Color.gray);

button1=newButton("yes");

button2=newButton("No");

add(button1);

add(button2);

}

publicvoidstart()

{sum=0;

for(inti=1;i<=100;i++)

{sum=sum+i;

}

}

publicvoidstop(){}

publicvoidpaint(Graphicsg)

{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

importjava.awt.;

importjava.applet.;

publicclassExample12_2extendsApplet

{intx=0,y=0;

publicvoidinit()

{Strings1=getParameter("girl");//从html得到"girl"的值。

Strings2=getParameter("boy");//从html得到"boy"的值。

x=Integer.parseInt(s1);

y=Integer.parseInt(s2);

}

publicvoidpaint(Graphicsg)

{g.drawString("x="+x+","+"y="+y,90,120);

}

}

Boy.html













例子3

importjava.applet.;

importjava.awt.;

importjava.awt.event.;

importjava.net.;

publicclassBoyextendsAppletimplementsActionListener

{Buttonbutton;

URLurl;

TextFieldtext;

publicvoidinit()

{text=newTextField(18);

button=newButton(“确定”);

add(newLabel(“输入网址:”));

add(text);add(button);

button.addActionListener(this);

}

publicvoidactionPerformed(ActionEvente)

{if(e.getSource()==button)

{try{url=newURL(text.getText().trim());

getAppletContext().showDocument(url);

}

catch(MalformedURLExceptiong)

{text.setText(“不正确的URL:"+url);

}

}

}

}





例子4

importjava.applet.;

importjava.awt.;

importjava.net.;

importjava.io.;

publicclassReadFileextendsApplet

{TextAreatext;

URLurl;

publicvoidinit()

{text=newTextArea(12,40);

add(text);

}

publicvoidstart()

{try{url=newURL(getCodeBase(),"hello.txt");

InputStreamin=url.openStream();//url返回输入流

intn=-1;

byteb[]=newbyte[100];

while((n=in.read(b))!=-1)

{Stringstr=newString(b,0,n);

text.append(str);

}

}

catch(Exceptionee){}

}

}







例子5

importjava.applet.;

importjava.awt.;

importjava.awt.event.;

publicclassCircleAndRectextends

AppletimplementsRunnable

{Threadleft,right;

Graphicsmypen;

intx,y;

publicvoidinit()

{left=newThread(this);

right=newThread(this);

x=10;y=10;

mypen=getGraphics();

}

publicvoidstart()

{try{left.start();

right.start();

}

catch(Exceptione){}

}

publicvoidrun()

{while(true)

{if(Thread.currentThread()==left)

{x=x+1;

if(x>240)x=10;

mypen.setColor(Color.blue);

mypen.clearRect(10,10,300,40);

mypen.drawRect(10+x,10,40,40);

try{left.sleep(60);

}

catch(InterruptedExceptione){}

}

elseif(Thread.currentThread()==right)

{y=y+1;

if(y>240)y=10;mypen.setColor(Color.red);

mypen.clearRect(10,90,300,40);

mypen.drawOval(10+y,90,40,40);

try{right.sleep(60);

}

catch(InterruptedExceptione){}

}

}

}

}





例子6



（1）客户端

importjava.net.;

importjava.io.;

importjava.awt.;

importjava.applet.;

publicclassClientextendsAppletimplementsRunnable

{TextFieldtext;

Socketsocket=null;

ObjectInputStreamin=null;

ObjectOutputStreamout=null;

Threadthread;

publicvoidinit()

{thread=newThread(this);

}

publicvoidstart()

{try{thread.start();

socket=newSocket(this.getCodeBase().getHost(),4331);

in=newObjectInputStream(socket.getInputStream());

out=newObjectOutputStream(socket.getOutputStream());

}

catch(Exceptione){}

}

publicvoidrun()

{Strings=null;

while(true)

{try{text=(TextField)in.readObject();

add(text);

validate();

return;

}

catch(Exceptione){}

}

}

}



（2）服务器端

importjava.io.;

importjava.net.;

importjava.util.;

importjava.awt.;

publicclassServer

{publicstaticvoidmain(Stringargs[])

{ServerSocketserver=null;

Server_threadthread;

Socketyou=null;

while(true)

{try{server=newServerSocket(4331);

}

catch(IOExceptione1)

{System.out.println("正在监听");

}

try{you=server.accept();

}

catch(IOExceptione){}

if(you!=null)

{newServer_thread(you).start();

}

}

}

}

classServer_threadextendsThread

{Socketsocket;

ObjectOutputStreamout=null;

ObjectInputStreamin=null;

Strings=null;

Server_thread(Sockett)

{socket=t;

try{out=newObjectOutputStream(socket.getOutputStream());

in=newObjectInputStream(socket.getInputStream());

}

catch(IOExceptione){}

}

publicvoidrun()

{TextFieldtext=newTextField("你好，我是服务器",20);

try{out.writeObject(text);

}

catch(IOExceptione){}

}

}