这个JAX-WS客户端调用线程是否安全？

Question

由于WS客户端服务和端口的初始化需要很长时间，我喜欢在启动时初始化它们并重用相同的端口实例。 初始化看起来像这样：

private static RequestContext requestContext = null;

static
{
    MyService service = new MyService(); 
    MyPort myPort = service.getMyServicePort(); 

    Map<String, Object> requestContextMap = ((BindingProvider) myPort).getRequestContext();
    requestContextMap = ((BindingProvider)myPort).getRequestContext(); 
    requestContextMap.put(BindingProvider.USERNAME_PROPERTY, uName); 
    requestContextMap.put(BindingProvider.PASSWORD_PROPERTY, pWord); 

    rc = new RequestContext();
    rc.setApplication("test");
    rc.setUserId("test");
}

我班上某个地方的电话：

myPort.someFunctionCall(requestContext, "someValue");

我的问题：这个电话会是线程安全的吗？

Answer 1

根据CXF FAQ：

  

JAX-WS客户端代理线程是否安全？

     

官方JAX-WS答案：不会。   根据JAX-WS规范，客户端代理不是线程安全的。   要编写可移植代码，您应该将它们视为非线程安全的   同步访问或使用实例池或类似实例。

     

CXF回答：对于许多用例，CXF代理是线程安全的。该   例外是：

     

  

• 根据JAX-WS规范使用((BindingProvider)proxy).getRequestContext()，   请求上下文是PER INSTANCE。因此，任何设置都会   影响其他线程上的请求。使用CXF，您可以：

  ((BindingProvider)proxy).getRequestContext().put("thread.local.request.context","true");
  

       

  以及对getRequestContext（）的未来调用将使用一个线程   本地请求上下文。这允许请求上下文   线程安全的。 （注意：响应上下文在CXF中始终是线程本地的）

  

• 管道上的设置 - 如果您直接使用代码或配置   操纵管道（如设置TLS设置或类似设置），那些   不是线程安全的。导管是每个实例，因此是那些   设置将被共享。此外，如果您使用FailoverFeature和   LoadBalanceFeatures，管道被动态替换。从而，   导管上设置的设置可能会在使用之前丢失   设置线程。

  
• 会话支持 - 如果您启用会话支持（请参阅   jaxws spec），会话cookie存储在管道中。因此，它   将在管道设置中落入上述规则，从而被共享   跨线程。
  
• WS-Security令牌 - 如果使用WS-SecureConversation或   WS-Trust，检索到的令牌缓存在端点/代理中以避免   额外（和昂贵）调用STS获取令牌。从而，   多个线程将共享令牌。如果每个线程有不同   安全凭证或要求，您需要使用单独的代理   实例
  

     

对于管道问题，您可以安装新的   使用本地或类似线程的ConduitSelector。那是一点点   虽然复杂。

     

对于大多数“简单”用例，您可以在多个上使用CXF代理   线程。以上概述了其他人的解决方法。

Answer 2

一般来说，没有。

根据CXF常见问题http://cxf.apache.org/faq.html#FAQ-AreJAX-WSclientproxiesthreadsafe?

  

官方JAX-WS回答：否。根据JAX-WS规范，客户端   代理不是线程安全的。要编写可移植代码，您应该对待   它们作为非线程安全并同步访问或使用池   实例或类似。

     

CXF回答：对于许多用例，CXF代理是线程安全的。

有关例外情况，请参阅常见问题解答。

Answer 3

正如您从上面的答案中看到的那样，JAX-WS客户端代理不是线程安全的，所以我只想分享我的实现，其他人将缓存客户端代理。 我实际上遇到了同样的问题，并决定创建一个执行JAX-WS客户端代理缓存的spring bean。您可以查看更多详细信息docs

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import javax.annotation.PostConstruct;

import org.apache.commons.lang3.concurrent.BasicThreadFactory;
import org.apache.logging.log4j.Logger;
import org.springframework.stereotype.Component;

/**
 * This keeps the cache of MAX_CUNCURRENT_THREADS number of
 * appConnections and tries to shares them equally amongst the threads. All the
 * connections are created right at the start and if an error occurs then the
 * cache is created again.
 *
 */
/*
 *
 * Are JAX-WS client proxies thread safe? <br/> According to the JAX-WS spec,
 * the client proxies are NOT thread safe. To write portable code, you should
 * treat them as non-thread safe and synchronize access or use a pool of
 * instances or similar.
 *
 */
@Component
public class AppConnectionCache {

 private static final Logger logger = org.apache.logging.log4j.LogManager.getLogger(AppConnectionCache.class);

 private final Map<Integer, MyService> connectionCache = new ConcurrentHashMap<Integer, MyService>();

 private int cachedConnectionId = 1;

 private static final int MAX_CUNCURRENT_THREADS = 20;

 private ScheduledExecutorService scheduler;

 private boolean forceRecaching = true; // first time cache

 @PostConstruct
 public void init() {
  logger.info("starting appConnectionCache");
  logger.info("start caching connections"); ;;
  BasicThreadFactory factory = new BasicThreadFactory.Builder()
    .namingPattern("appconnectioncache-scheduler-thread-%d").build();
  scheduler = Executors.newScheduledThreadPool(1, factory);

  scheduler.scheduleAtFixedRate(new Runnable() {
   @Override
   public void run() {
    initializeCache();
   }

  }, 0, 10, TimeUnit.MINUTES);

 }

 public void destroy() {
  scheduler.shutdownNow();
 }

 private void initializeCache() {
  if (!forceRecaching) {
   return;
  }
  try {
   loadCache();
   forceRecaching = false; // this flag is used for initializing
   logger.info("connections creation finished successfully!");
  } catch (MyAppException e) {
   logger.error("error while initializing the cache");
  }
 }

 private void loadCache() throws MyAppException {
  logger.info("create and cache appservice connections");
  for (int i = 0; i < MAX_CUNCURRENT_THREADS; i++) {
   tryConnect(i, true);
  }
 }

 public MyPort getMyPort() throws MyAppException {
  if (cachedConnectionId++ == MAX_CUNCURRENT_THREADS) {
   cachedConnectionId = 1;
  }
  return tryConnect(cachedConnectionId, forceRecaching);
 }

 private MyPort tryConnect(int threadNum, boolean forceConnect) throws MyAppException {
  boolean connect = true;
  int tryNum = 0;
  MyPort app = null;
  while (connect && !Thread.currentThread().isInterrupted()) {
   try {
    app = doConnect(threadNum, forceConnect);
    connect = false;
   } catch (Exception e) {
    tryNum = tryReconnect(tryNum, e);
   }
  }
  return app;
 }

 private int tryReconnect(int tryNum, Exception e) throws MyAppException {
  logger.warn(Thread.currentThread().getName() + " appservice service not available! : " + e);
  // try 10 times, if
  if (tryNum++ < 10) {
   try {
    logger.warn(Thread.currentThread().getName() + " wait 1 second");
    Thread.sleep(1000);
   } catch (InterruptedException f) {
    // restore interrupt
    Thread.currentThread().interrupt();
   }
  } else {
   logger.warn(" appservice could not connect, number of times tried: " + (tryNum - 1));
   this.forceRecaching = true;
   throw new MyAppException(e);
  }
  logger.info(" try reconnect number: " + tryNum);
  return tryNum;
 }

 private MyPort doConnect(int threadNum, boolean forceConnect) throws InterruptedException {
  MyService service = connectionCache.get(threadNum);
  if (service == null || forceConnect) {
   logger.info("app service connects : " + (threadNum + 1) );
   service = new MyService();
   connectionCache.put(threadNum, service);
   logger.info("connect done for " + (threadNum + 1));
  }
  return service.getAppPort();
 }
}

Answer 4

一般的解决方案是在池中使用多个客户端对象，然后使用充当外观的代理。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: customer-ratings
  labels:
    app: product-ratings-vue
spec:
  replicas: 1
  selector:
    matchLabels:
      app: product-ratings-vue
  template:
    metadata:
      labels:
        app: product-ratings-vue 
    spec:
      containers: 
      - name: api-service
        image: api-service
        ports:
          - containerPort: 8080
          - containerPort: 8000
        resources: {}
        volumeMounts:
          - mountPath: /usr/local/tomcat/logs
            name: api-service-claim 

# ekomi-import       
      - name: ekomi-import
        image: ekomi-import
        resources: {}

# cache
      - name: cache
        image: cache
        resources:
          limits:
            memory: "536870912"

# storage
      - name: storage
        image: storage
        ports:
         - containerPort: 7000
         - containerPort: 7001
         - containerPort: 7199
         - containerPort: 9042
         - containerPort: 9160
        resources: {}
# view
      - name: view
        image: view
        ports:
         - containerPort: 3000
        resources: {}

 # tomcat
      - name: tomcat
        image: tomcat
# node
      - name: node
        image: node
        resources: {}
# openJdk
      - name: node
        image: node
        resources: {}

      volumes:
        - name: api-service-claim
          persistentVolumeClaim:
            claimName: api-service-claim

使用代理：

import org.apache.commons.pool2.BasePooledObjectFactory;
import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.impl.DefaultPooledObject;
import org.apache.commons.pool2.impl.GenericObjectPool;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

class ServiceObjectPool<T> extends GenericObjectPool<T> {
        public ServiceObjectPool(java.util.function.Supplier<T> factory) {
            super(new BasePooledObjectFactory<T>() {
                @Override
                public T create() throws Exception {
                    return factory.get();
                }
            @Override
            public PooledObject<T> wrap(T obj) {
                return new DefaultPooledObject<>(obj);
            }
        });
    }

    public static class PooledServiceProxy<T> implements InvocationHandler {
        private ServiceObjectPool<T> pool;

        public PooledServiceProxy(ServiceObjectPool<T> pool) {
            this.pool = pool;
        }


        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            T t = null;
            try {
                t = this.pool.borrowObject();
                return method.invoke(t, args);
            } finally {
                if (t != null)
                    this.pool.returnObject(t);
            }
        }
    }

    @SuppressWarnings("unchecked")
    public T getProxy(Class<? super T> interfaceType) {
        PooledServiceProxy<T> handler = new PooledServiceProxy<>(this);
        return (T) Proxy.newProxyInstance(interfaceType.getClassLoader(),
                                          new Class<?>[]{interfaceType}, handler);
    }
}