Java Lambda表达式中的模式匹配

我正在使用Picocli创建CLI应用程序。下面的代码驻留在我的一个类的run方法中。它使用Picocli提供的CommandLine.execute命令执行

我无法找出这段代码中出现空指针的原因：

        selectedDevices.stream().parallel().forEach((device) -> {
        try {

            String result = SSH.EXECUTE(user, password, device.getAddress(), SSH.Cisco_Login.FORMAT_COMMAND("show run access-group"));
            String pattern = "(?<=access-group)(?<accessgroup>.*?)(?=in)|(?<=interface)(?<interface>.*)";
            Matcher m = Pattern.compile(pattern,Pattern.CASE_INSENSITIVE | Pattern.MULTILINE).matcher(result);
            //show the progress.
            System.out.println(result);

            while (m.find()) {
                String accessgroup = m.group("accessgroup").trim();
                String interface1 = m.group("interface").trim();
                System.out.println("accessgroup= " + accessgroup + " interface=" + interface1);
            }

        } catch (JSchException | IOException ex) {
            System.out.println("Catching Exception");
            Logger.getLogger(AccessGroupCommand.class.getName()).log(Level.SEVERE, null, ex);
        }

    });

完整错误消息：

java.lang.NullPointerException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.util.concurrent.ForkJoinTask.getThrowableException(ForkJoinTask.java:598)
at java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:677)
at java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:735)
at java.util.stream.ForEachOps$ForEachOp.evaluateParallel(ForEachOps.java:160)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateParallel(ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:233)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:583)
at Tufin.AccessGroupCommand.run(InterfaceMagicCLI.java:351)
at picocli.CommandLine.executeUserObject(CommandLine.java:1666)
at picocli.CommandLine.access$900(CommandLine.java:144)
at picocli.CommandLine$RunAll.handle(CommandLine.java:2094)
at picocli.CommandLine$RunAll.handle(CommandLine.java:2053)
at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:1872)
at picocli.CommandLine.execute(CommandLine.java:1801)
at Tufin.InterfaceMagicCLI.main(InterfaceMagicCLI.java:86)
 Caused by: java.lang.NullPointerException
at Tufin.AccessGroupCommand.lambda$run$0(InterfaceMagicCLI.java:363)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
at java.util.stream.ForEachOps$ForEachTask.compute(ForEachOps.java:291)
at java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:731)
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

使用类似正则表达式的

（？Foo）|（？Bar）

，每次

find（）

迭代只能使用

a

和

B

中的一个，另一个将为

null

这意味着：

String a = m.group("A").trim();
String b = m.group("B").trim();

---

将始终导致NullPointerException，因为其中一个将无法调用

trim（）

device.getAddress（）？如果它为null，则根据SSH.EXECUTE方法，它可能会抛出itNo，即模式匹配中的itNo。我认为while（m.find（））是我需要执行的唯一检查。我错过什么了吗？啊！我应该如何更改正则表达式以捕获这两个参数？

String a = m.group("A").trim();
String b = m.group("B").trim();