问题在CLIENT端输入圆半径让SERVER传回计算后圆的周长.doc

RMIMath範例(JDK1.2.2)
問題:在CLIENT端輸入圓半徑讓SERVER傳回計算後圓的周長

1.開啟新Project，命名為math.jpr
INTERFACE(新增Mathe.java檔案到Project)
packagemath;
publicinterfaceMatheextendsjava.rmi.Remote
{
publicdoublegetRadius(doubler)throwsjava.rmi.RemoteException;
}

Implement(新增MatheImpl.java檔案到Project)
packagemath;
importjava.rmi.*;
importjava.lang.Math;
importjava.rmi.Naming;
importjava.rmi.server.UnicastRemoteObject;

publicclassMatheImplextendsUnicastRemoteObjectimplementsMathe{ publicMatheImpl()throwsRemoteException { super(); } publicdoublegetRadius(doubler)throwsRemoteException { return2*Math.PI*r; } publicstaticvoidmain(Stringargs[]) { System.setSecurityManager(newRMISecurityManager()); try { MatheImplmath=newMatheImpl(); Naming.rebind("rmi://140.127.43.245/MathServer",math); System.out.println("serverstart...."); } catch(Exceptione) { System.out.println("Servererror:"+e); System.exit(0); } }}
File->New->Applet(產生MatheApplet1.java及MatheApplet1.html)
packagemath;importjava.awt.*;importjava.awt.event.*;importjava.applet.*;importjava.rmi.*;publicclassMatheApplet1extendsApplet{booleanisStandalone=false;Labellabel1=newLabel();TextFieldradius=newTextField();Labellabel2=newLabel();TextFieldresult=newTextField();Buttonsend=newButton();Mathema;doubleres;//GetaparametervaluepublicStringgetParameter(Stringkey,Stringdef){returnisStandalone?System.getProperty(key,def):(getParameter(key)!=null?getParameter(key):def);}//ConstructtheappletpublicMatheApplet1(){}//Initializetheappletpublicvoidinit(){try{jbInit();}catch(Exceptione){e.printStackTrace();}}//ComponentinitializationprivatevoidjbInit()throwsException{label1.setBounds(newRectangle(37,14,89,36));label1.setFont(newjava.awt.Font("Dialog",0,14));label1.setForeground(Color.red);label1.setText("請輸入圓半徑");this.setLayout(null);radius.setBackground(Color.white);radius.setBounds(newRectangle(157,17,114,31));label2.setBounds(newRectangle(37,111,69,32));label2.setFont(newjava.awt.Font("Dialog",0,14));label2.setForeground(Color.blue);la