JAVA向SFTP中上传空文件做标记位

对于上传空文件

上传文件简单，但是如何创建一个空的输入流时突然难到了我。首先想到的是直接传null进入

得到的结果是

4: java.lang.NullPointerException
	at com.jcraft.jsch.ChannelSftp._put(ChannelSftp.java:697)
	at com.jcraft.jsch.ChannelSftp.put(ChannelSftp.java:540)
	at com.jcraft.jsch.ChannelSftp.put(ChannelSftp.java:492)
	at com.juneyaoair.com.SFTPTest.testAddEmptyFile2(SFTPTest.java:39)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.NullPointerException
	at com.jcraft.jsch.ChannelSftp._put(ChannelSftp.java:636)
	... 25 more

第二次尝试

我想到了System.in 的源码 public final static InputStream in = null;

则出现的问题是程序hung住了。

第三次尝试

这次终于成功了，上面不停止的原因为没有收到-1的结束标志

    @Test
    public void testAddEmptyFile2() {
    
    

        Channel channel = null;
        ChannelSftp sftp = null;
        try {
    
    

            JSch jSch = new JSch();
            Session session = jSch.getSession("admin", "192.168.56.101", 2294);
            session.setPassword("admin");
            Properties config = new Properties();
            config.put("StrictHostKeyChecking", "no");

            session.setConfig(config);
            session.connect();
            channel = session.openChannel("sftp");
            channel.connect();
            sftp = (ChannelSftp) channel;
            sftp.cd("/upload");
            InputStream is = new InputStream() {
    
    
                @Override
                public int read() throws IOException {
    
    
                    return -1;//直接结束
                }
            };
            sftp.put(is, "emptyFile.txt");

            Vector<ChannelSftp.LsEntry> files = sftp.ls("/upload");
            files.forEach(r -> System.out.println(r.getFilename()));

            Assert.assertTrue(true);
        } catch (Exception e) {
    
    
            e.printStackTrace();
        } finally {
    
    
            assert sftp != null;
            sftp.disconnect();
            channel.disconnect();
        }
    }