Question

我正在尝试编写一个多线程的Web服务，每个服务从一个线程调用4个webservices。当我尝试直接调用webservice时，它可以工作。但是当我尝试从一个线程调用它会抛出一个NullPointerException。有什么想法吗？

@WebService(serviceName = "Negotiator")
public class Negotiator implements Runnable{
@WebServiceRef(wsdlLocation = "WEB-INF/wsdl/localhost_8080/Negotiate4/Negotiate4.wsdl")
private Negotiate4_Service service_3;
@WebServiceRef(wsdlLocation = "WEB-INF/wsdl/localhost_8080/Negotiate3/Negotiate3.wsdl")
private Negotiate3_Service service_2;
@WebServiceRef(wsdlLocation = "WEB-INF/wsdl/localhost_8080/Negotiate2/Negotiate2.wsdl")
private Negotiate2_Service service_1;
@WebServiceRef(wsdlLocation = "WEB-INF/wsdl/localhost_8080/Negotiate1/Negotiate1.wsdl")
private Negotiate1_Service service;

private String ret[] = new String[10];
private Thread t[] = new Thread[10];

/**
 * This is a sample web service operation
 */
@WebMethod(operationName = "hello")
public String hello(@WebParam(name = "name") String txt) {
    try {
    Thread t1 = new Thread(new Negotiator(),"prov1");
    Thread t2 = new Thread(new Negotiator(),"prov2");
    Thread t3 = new Thread(new Negotiator(),"prov3");
    Thread t4 = new Thread(new Negotiator(),"prov4");
    t1.start();
    t2.start();
    t3.start();
    t4.start();

    t1.join();
    t2.join();
    t3.join();
    t4.join();
    }
    catch(java.lang.InterruptedException e)
    {
        System.out.println("Exception: "+e);
    }
    String retString = "";
    for(int i=0;i<4;i++) {
        retString = retString + ret[i];
    }
    return "Hello " + retString + " !";
}

 @Override
public void run()
{
    Thread th = Thread.currentThread();
    System.out.println("Inside run "+ th.getName());
    switch (th.getName()) {
        case "prov1":
            ret[0] = negotiate("Hi1");
            break;
        case "prov2":
            ret[1] = negotiate_1("Hi2");
            break;
        case "prov3":
            ret[2] = negotiate_2("Hi3");
            break;
        default:
            ret[3] = negotiate_3("Hi4");
            break;
    }
}

private String negotiate(java.lang.String name) {

    org.prov1.Negotiate1 port1 = service.getNegotiate1Port();
    return port1.negotiate(name);
}

private String negotiate_1(java.lang.String name) {

    org.prov2.Negotiate2 port2 = service_1.getNegotiate2Port();
    return port2.negotiate(name);
}

private String negotiate_2(java.lang.String name) {

    org.prov3.Negotiate3 port3 = service_2.getNegotiate3Port();
    return port3.negotiate(name);
}

private String negotiate_3(java.lang.String name) {

    org.prov4.Negotiate4 port4 = service_3.getNegotiate4Port();
    return port4.negotiate(name);
}
}

当我尝试从hello方法内部调用协商操作时，它可以工作。但是当从run（）内部调用negotiate时，我得到一个NullPointerException。请帮忙。

Answer 1

问题是在当前线程中处理@WebServiceRef，并且很可能容器通过代理保持线程本地引用。如果您使用的是Java EE7容器，则可以尝试使用ManagedExecutorService来调用方法，但不确定它是否有效。一切都取决于谁以及如何初始化服务类。提供有关设置的更多详细信息。

从线程调用Web服务时出现空指针异常

1 个答案: