Question

通过我自己的插件，我需要知道Jenkins slave的工作区中是否存在文件。但是无法找到该文件，而它确实存在于从属文件（D:\workspace\JOB_NAME\test.txt）上。

public class MyBuilder extends Builder implements Serializable {

    private static final long serialVersionUID = 1L;

    public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) 
            throws InterruptedException, IOException {

        FilePath fp = new FilePath(build.getWorkspace(), "test.txt");

        String result = fp.act(new FileCallable<String>() {
            private static final long serialVersionUID = 1L;

            @Override
            public String invoke(File file, VirtualChannel channel) throws IOException, InterruptedException {
                if (file.getAbsoluteFile().exists()){
                    return file.getName() + " exists.";
                } else {
                    return file.getName() + " doesn't exist.";
                }
            }
        });

        System.out.println("result: " + result);

结果：

FATAL: remote file operation failed: D:\workspace\JOB_NAME\test.txt at hudson.remoting.Channel@182752b:Slave
hudson.util.IOException2: remote file operation failed: D:\workspace\JOB_NAME\test.txt at hudson.remoting.Channel@182752b:Slave
    at hudson.FilePath.act(FilePath.java:900)
    at hudson.FilePath.act(FilePath.java:877)
    at com.company.tlb.proj.MyBuilder.perform(Unknown Source)
    at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
    at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:804)
    at hudson.model.Build$BuildExecution.build(Build.java:199)
    at hudson.model.Build$BuildExecution.doRun(Build.java:160)
    at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:586)
    at hudson.model.Run.execute(Run.java:1575)
    at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
    at hudson.model.ResourceController.execute(ResourceController.java:88)
    at hudson.model.Executor.run(Executor.java:237)
Caused by: java.io.IOException: Unable to serialize hudson.FilePath$FileCallableWrapper@18b91cb
    at hudson.remoting.UserRequest.serialize(UserRequest.java:166)
    at hudson.remoting.UserRequest.<init>(UserRequest.java:62)
    at hudson.remoting.Channel.call(Channel.java:671)
    at hudson.FilePath.act(FilePath.java:893)
    ... 11 more
Caused by: java.io.NotSerializableException: java.io.PrintStream
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1164)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
    at hudson.remoting.UserRequest._serialize(UserRequest.java:155)
    at hudson.remoting.UserRequest.serialize(UserRequest.java:164)
    ... 14 more

我做错了什么？

链接：

Answer 1

您正在将一个匿名内部类传递给act(...)，该内联类具有对其父类MyBuilder的隐式引用。我的猜测是即使MyBuilder实现了Serializable，它实际上也不能被序列化，因为有些引用不是Serializable的另一个对象（例如java.io.PrintStream堆栈跟踪表明）。

使FileCallable<String>的实例成为一个静态内部类，以摆脱对其父级的隐式引用：

private static class MyFileCallable implements FileCallable<String> {
  private static final long serialVersionUID = 1L;
  @Override
  public String invoke(File file, VirtualChannel channel) throws IOException, InterruptedException {
    if (file.getAbsoluteFile().exists()){
      return file.getName() + " exists.";
    } else {
      return file.getName() + " doesn't exist.";
    }
  }
}

然后使用它：

String result = fp.act(new MyFileCallable());

<强>更新这是Java Nested Classes教程的链接，该教程概述了内部类的实例与其封闭的外部类实例之间的关系：

InnerClass的一个实例只能存在于一个实例中 OuterClass并且可以直接访问其方法和字段封闭实例。

这也在JLS（§8.1.3 Inner Classes and Enclosing Instances）中以更多技术术语解释。

考虑到这一点，来自Serializable doc的引用解释了您遇到NotSerializableException的原因：

遍历图形时，可能遇到没有的对象支持Serializable接口。在这种情况下将抛出NotSerializableException并将标识该类不可序列化的对象。

Jenkins插件无法访问slave上的文件

1 个答案: