Java 从servlet调用RMI方法

我正在编写一个servlet，可以调用rmi。我已经编写了RMI服务器，并用JavaSwing客户机对其进行了测试，一切正常。但是我在使用servlet时遇到了一个问题。 当用户打开主web页面时，servlet自动调用rmi方法来检索数据库中的一些信息，然后构建web页面来显示。 当用户单击触发另一个调用另一个rmi方法的servlet的某个链接时，我得到一个错误：

java.rmi.ConnectException: Connection refused to host: 192.168.1.101; nested exception is: 
java.net.ConnectException: Connection refused
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:619)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:340)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at project.RemoteClass.getEngine(RemoteClass.java:33)
at project.MainServlet.processRequest(MainServlet.java:57)
at project.MainServlet.doGet(MainServlet.java:176)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at java.net.Socket.<init>(Socket.java:425)
at java.net.Socket.<init>(Socket.java:208)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:146)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:613)

当此代码执行registry.lookup方法时，会出现此错误。 我怎样才能解决它

拒绝连接到主机：192.168.1.101 ... 位于sun.rmi.registry.RegistryImpl\u Stub.lookup（未知源）

192.168.1.101上没有运行的注册表，在本例中是在端口22222上运行的，您称之为

LocateRegistry.getRegistry（“192.168.1.101”，22222）。

---

也许你的注册表在第一次呼叫后退出。如果您使用

LocateRegistry.createRegistry（）

在服务器上创建它，并且不将结果存储在静态字段中，那么它很容易被垃圾收集

192.168.1.101真的有一台服务器在监听端口22222吗？在正确的界面上？你能通过telnet看看它是否有效吗？当然，它很有效。另外，如果它不起作用，第一个rmi调用也会失败。您真的需要不断地重新分配

接口\u引擎

静态字段吗？嗯，不，它不应该是静态的，但我不想每次servlet需要调用远程方法时都创建RemoteClass对象！但你还是这么做。请注意，每次方法执行

RemoteClass#getEngine

时，您总是执行

interface_engine=（RemoteInterface）registry.lookup（skeleton），这很奇怪（甚至奇怪，因为此方法不是线程安全的）。
public class RemoteClass {
    private RemoteClass(){}
    private static Registry registry = null;
    private static RemoteInterface interface_engine = null;
    private static final String rmiAddress = "192.168.1.101";
    private static final int rmiPort = 22222;
    private static final String skeleton = "ProjRMISkeleton";

    public static RemoteInterface getEngine() throws RemoteException {
        registry = LocateRegistry.getRegistry(rmiAddress, rmiPort);
        try {
            interface_engine = (RemoteInterface) registry.lookup(skeleton);
        } catch (RemoteException ex) {
            Logger.getLogger(MainServlet.class.getName()).log(Level.SEVERE, null, ex);
        } catch (NotBoundException ex) {
            Logger.getLogger(MainServlet.class.getName()).log(Level.SEVERE, null, ex);
        }
        return interface_engine;
    }
}