本文通过一个四则运算实例来展示一个基于Java的CORBA应用，范例如下：
一、定义IDL
module zzvcom{
module cbrtest{
interface Calc{
void add(in long a,in long b,out long c);
void sub(in long a,in long b,out long c);
void muti(in long a,in long b,out long c);
void div(in long a,in long b,out long c);
};
};
};
二、根据IDL生成存根和代理等代码
idlj -fall Hello.idl
三、开发CORBA服务
import org.omg.CORBA.IntHolder;
import org.omg.CORBA.ORB;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContextExt;
import org.omg.CosNaming.NamingContextExtHelper;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.POAHelper;
import zzvcom.cbrtest.Calc;
import zzvcom.cbrtest.CalcHelper;
import zzvcom.cbrtest.CalcPOA;
/**
* 四则运算的服务端实现
*
*/
class CalcImpl extends CalcPOA {
private ORB orb;
public void setORB(ORB orb_val) {
orb = orb_val;
}
public void add(int a, int b, IntHolder c) {
c.value = a + b;
}
public void sub(int a, int b, IntHolder c) {
c.value = a - b;
}
public void muti(int a, int b, IntHolder c) {
c = new IntHolder(a * b);
}
public void div(int a, int b, IntHolder c) {
c = new IntHolder(a / b);
}
public void shutdown() {
orb.shutdown(false);
}
}
public class CalcServer {
public static void main(String args[]) {
try {
//创建一个ORB实例
ORB orb = ORB.init(args, null);
//得到一个RootPOA的引用，并激活POAManager
POA rootpoa = POAHelper.narrow(orb.resolve_initial_references("RootPOA"));
rootpoa.the_POAManager().activate();
//创建一个CalcImpl实例（servant），并注册到ORB上
CalcImpl calcImpl = new CalcImpl();
calcImpl.setORB(orb);
//从服务中得到对象的引用
org.omg.CORBA.Object ref = rootpoa.servant_to_reference(calcImpl);
Calc href = CalcHelper.narrow(ref);
//得到一个根名称的上下文
org.omg.CORBA.Object objRef = orb.resolve_initial_references("NameService");
NamingContextExt ncRef = NamingContextExtHelper.narrow(objRef);
//在命名上下文中绑定这个对象
String name = "Calc";
NameComponent path[] = ncRef.to_name(name);
ncRef.rebind(path, href);
System.out.println("CalcServer ready and waiting ...");
//启动线程服务，等待客户端的调用
orb.run();
} catch (Exception e) {
System.err.println("ERROR: " + e);
e.printStackTrace(System.out);
}
System.out.println("CalcServer Exiting ...");
}
}
四、开发客户端
import org.omg.CORBA.IntHolder;
import org.omg.CORBA.ORB;
import org.omg.CosNaming.NamingContextExt;
import org.omg.CosNaming.NamingContextExtHelper;
import zzvcom.cbrtest.Calc;
import zzvcom.cbrtest.CalcHelper;
/**
* 四则运算的客户端调用
*
*/
public class CalcClient {
static Calc calcImpl;
public static void main(String args[]) {
try {
//创建一个ORB实例
ORB orb = ORB.init(args, null);
//获取根名称上下文
org.omg.CORBA.Object objRef = orb.resolve_initial_references("NameService");
NamingContextExt ncRef = NamingContextExtHelper.narrow(objRef);
//从命名上下文中获取接口实现对象
String name = "Calc";
calcImpl = CalcHelper.narrow(ncRef.resolve_str(name));
//调用接口对象的方法
System.out.println("Obtained a handle on server object: " + calcImpl);
System.out.println();
IntHolder add_val = new IntHolder();
calcImpl.add(1, 2, add_val);
System.out.println(add_val.value);
} catch (Exception e) {
System.out.println("ERROR : " + e);
e.printStackTrace(System.out);
}
}
}
五、启动CORBA服务器
先编译所有的Java文件：javac -Xlint:unchecked -d . *.java
编译后就可以调用了。