Java 从运行在Tomcat中的webapp写入套接字时出现NullPointerException

我在写套接字时遇到了一个奇怪的问题。该应用程序是一个在Tomcat 5.5下运行的Web应用程序。 所讨论的功能是从servlet接收请求，进行一些处理，然后通过SSLSocket将该请求发送到外部系统

这是我的MessageProcessor类：

public class MessageProcessor {

    private final int socketTimeout;
    private final int threadTimeout;

    private final ExecutorService executor = Executors.newCachedThreadPool();

    private static class Holder {
        static MessageProcessor instance = new MessageProcessor();
    }

    public static MessageProcessor instance() {
        return Holder.instance;
    }
    static {
        instance();
    }

    private MessageProcessor() {
        socketTimeout = /*get from property*/
                threadTimeout = /*get from property*/

                    //Setting Java SSL details
                    System.setProperty("javax.net.ssl.trustStore") /*from property*/;
        System.setProperty("javax.net.ssl.trustStorePassword") /*from property*/;

        socketFactory = SSLSocketFactory.getDefault();
    }

    public String submit(String msg) {
        Worker worker = new Worker(msg);
        try {
            return executor.submit(worker).get(threadTimeout,
                                               TimeUnit.MILLISECONDS);
        } catch (Exception e) {
            e.printStackTrade();
        }
        return "";
    }

    public String submitDirect(String msg) throws Exception {
        Worker worker = new Worker(msg);
        return worker.call();
    }

    class Worker implements Callable<String> {
        private String message;

        public Worker(String requestMsg) {
            this.message = requestMsg;
        }

        public String call() throws Exception {

            socket = socketFactory.createSocket();


            StringBuilder responseSb = new StringBuilder();
            StringBuilder frameMarkerSb = new StringBuilder();
            BufferedWriter socketWriter = null;
            BufferedReader socketReader = null;

            try {

                socketWriter =
                        new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
                socketWriter.write(message);
                socketWriter.flush();

                socketReader =
                        new BufferedReader(new InputStreamReader(socket.getInputStream(),
                                                                 "UTF-8"));
                /* do something else */
                /* receive response */

            } catch (InterruptedIOException e) {
                //Error handling
            } catch (Exception e) {
                //Error handling
            } finally {
                socketWriter.close();
                socketReader.close();
                socket.close();
            }
            return response;
        }
    }
}

---

问题在于submit（）。在submit（）中，任务被提交到缓存的线程池，并引发此异常。在socketWriter.flush（）上引发异常

如果我使用submitDirect（），则直接调用call（）方法，而不提交到线程池，并且工作正常

在JUnit中测试该类时没有问题。这只发生在Tomcat中

如果有人能解释一下，我将非常感激。对不起，如果我在这里放了很多代码。这让我发疯了

public String submitDirect(String pdcRequestStr) throws Exception {
    Worker worker = new Worker(msg);
    return worker.call();
}

---

将new Worker（msg）更改为new Worker（pdc requeststr）

我想我已经找到了问题的原因，该问题看起来来自这一行：

socketFactory = SSLSocketFactory.getDefault();

将SocketFactory放入线程局部变量后，它可以正常工作

socketFactory = new ThreadLocal<SocketFactory>(){;
    protected SocketFactory initialValue() {
        return SSLSocketFactory.getDefault();
    }
};

socketFactory=newthreadlocal（）{；
受保护的SocketFactory初始值（）{
返回SSLSocketFactory.getDefault（）；
}
};

---

所以我的结论是SSLSocketFactory不是线程安全的。不过，我还没有找到任何官方文档来支持这一点。

这是我的错别字。由于业务敏感性，在此处过帐之前已重命名变量。“在socketWriter.flush（）处引发异常”。不是根据你发布的堆栈跟踪。还有更多吗？发布了完整的堆栈跟踪。当我使用调试器逐步检查代码时，它在socketWriter.flush（）处失败。但是，堆栈跟踪仅与此类似

socketFactory = SSLSocketFactory.getDefault();

socketFactory = new ThreadLocal<SocketFactory>(){;
    protected SocketFactory initialValue() {
        return SSLSocketFactory.getDefault();
    }
};