java RMI(远程方法调用)
要实现java RMI,需要有以下几个步骤:
1、生成一个远程接口
2、实现远程对象(服务器端程序)
3、编写服务器程序
4、编写客户程序
5、注册远程对象
6、调用远程对象
下面以一个简单计算器的实例说明:
1、生成一个远程接口
import java.rmi.Remote;
import java.rmi.RemoteException;
//接口必须继承自java.rmi.Remote;
public interface ICalculator extends Remote {
//声明接口方法,每一个远程调用方法必须抛出java.rmi.RemoteException异常
public float add(float a,float b) throws RemoteException;
public float sub(float a,float b) throws RemoteException;
public float mult(float a,float b) throws RemoteException;
public float divide(float a,float b) throws RemoteException;
}
2、实现远程对象(服务器端程序)
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
//服务实现类必须继承自import java.rmi.server.UnicastRemoteObject;
public class CalculatorImpl extends UnicastRemoteObject implements ICalculator {
public CalculatorImpl() throws RemoteException{
super();
}
@Override
public float add(float a, float b) throws RemoteException {
// TODO Auto-generated method stub
return a + b;
}
@Override
public float sub(float a, float b) throws RemoteException {
// TODO Auto-generated method stub
return a - b;
}
@Override
public float mult(float a, float b) throws RemoteException {
// TODO Auto-generated method stub
return a*b;
}
@Override
public float divide(float a, float b) throws RemoteException {
// TODO Auto-generated method stub
return a/b;
}
}
3、编写服务器程序
import javax.naming.InitialContext;
public class CalcServer {
public static void main(String[] args){
try {
CalculatorImpl cal = new CalculatorImpl();
javax.naming.Context context = new InitialContext();
context.bind("rmi://localhost:1099/CalculatorService", cal);
System.out.println("server started...");
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
4、编写客户程序
import javax.naming.Context;
import javax.naming.InitialContext;
public class CalcClient {
public static void main(String[] args){
try {
Context context = new InitialContext();
//查找远程对象并调用远程方法
ICalculator cal = (ICalculator)context.lookup("rmi://localhost:1099/CalculatorService");
System.out.println(cal.add(1, 2));
System.out.println(cal.sub(1, 2));
System.out.println(cal.mult(1, 2));
System.out.println(cal.divide(1, 2));
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
5、注册远程对象
打开命令提示符,启动rmi注册程序:start rmiregistry回车,将弹出一个rmiregistry.exe窗口。
切换到.class文件所在的目录,注册并启动远程对象:java CalcServer
将打印server started...
6、调用远程对象
打开命令提示符,切换到.class文件所在的目录,调用客户端程序java CalcClient,将打印如下内容:
3.0
-1.0
2.0
0.5
posted on 2011-12-19 22:34 balabala已被注册 阅读(2249) 评论(0) 编辑 收藏 举报