上传文件时 NativeSshFile.setAttributes 出现 UnsupportedOperationException Apache Mina sshd 服务器

Question

我使用 Apache Mina SSHD 启动本地 SFTP 服务器。这是我的相关 . To testing I use WinSCP 作为我的 SFTP 客户端。我可以成功连接到服务器，也可以查看服务器根目录。但问题是，当我尝试将文件上传到该服务器根目录时。

我得到了

Exception caught in SFTP subsystem
java.lang.UnsupportedOperationException: null 
at org.apache.sshd.common.file.nativefs.NativeSshFile.setAttributes(NativeSshFile.java:634) ~[sshd-core-0.10.0.jar:0.10.0]
    at org.apache.sshd.server.sftp.SftpSubsystem.process(SftpSubsystem.java:427) ~[sshd-core-0.10.0.jar:0.10.0]
    at org.apache.sshd.server.sftp.SftpSubsystem.run(SftpSubsystem.java:334) ~[sshd-core-0.10.0.jar:0.10.0]
    at java.lang.Thread.run(Unknown Source) [na:1.7.0_75].

下面是我的相关日志文件。

10:30:46.758 [Thread-1] DEBUG o.a.s.c.file.nativefs.NativeSshFile - Authorized
10:30:46.767 [Thread-1] ERROR o.a.sshd.server.sftp.SftpSubsystem - Exception caught in SFTP subsystem
java.lang.UnsupportedOperationException: null
    at org.apache.sshd.common.file.nativefs.NativeSshFile.setAttributes(NativeSshFile.java:634) ~[sshd-core-0.10.0.jar:0.10.0]
    at org.apache.sshd.server.sftp.SftpSubsystem.process(SftpSubsystem.java:427) ~[sshd-core-0.10.0.jar:0.10.0]
    at org.apache.sshd.server.sftp.SftpSubsystem.run(SftpSubsystem.java:334) ~[sshd-core-0.10.0.jar:0.10.0]
    at java.lang.Thread.run(Unknown Source) [na:1.7.0_75]
10:30:46.767 [Thread-1] DEBUG o.a.s.server.channel.ChannelSession - Send SSH_MSG_CHANNEL_EOF on channel ChannelSession[id=0, recipient=256]
10:30:46.768 [Thread-1] DEBUG o.a.sshd.common.io.nio2.Nio2Session - Writing 64 bytes

还有我的maven依赖，

<dependency>
    <groupId>org.apache.mina</groupId>
    <artifactId>mina-core</artifactId>
    <version>2.0.9</version>
</dependency>
<dependency>
    <groupId>org.apache.sshd</groupId>
    <artifactId>sshd-sftp</artifactId>
    <version>0.9.0</version>
</dependency>
<dependency>
    <groupId>org.apache.sshd</groupId>
    <artifactId>sshd-core</artifactId>
    <version>0.10.0</version>
</dependency>

我想知道在将文件上传到本地 SFTP 服务器时如何克服上述问题。谢谢。

Answer 1

上传文件时，WinSCP根据其配置设置上传文件时间戳（默认开启）and/or权限（默认关闭）。

Mina SSHD 0.10.0不支持设置文件属性

public void setAttributes(Map<Attribute, Object> attributes) throws IOException {
    if (!attributes.isEmpty()) {
        throw new UnsupportedOperationException();
    }
}

最新的 Mina SSHD 0.14.0 确实支持设置时间戳，默认情况下只记录它不能设置权限（或其他属性）。

public void setAttributes(Map<Attribute, Object> attributes) throws IOException {
    Set<Attribute> unsupported = new HashSet<Attribute>();
    for (Attribute attribute : attributes.keySet()) {
        Object value = attributes.get(attribute);
        switch (attribute) {
        case Size: {
            long newSize = (Long) value;
            FileChannel outChan = new FileOutputStream(file, true).getChannel();
            outChan.truncate(newSize);
            outChan.close();
            continue;
        }
        case LastModifiedTime:
            setLastModified((Long) value);
            break;
        default:
            unsupported.add(attribute);
            break;
        }
    }
    handleUnsupportedAttributes(unsupported);
}

protected void handleUnsupportedAttributes(Collection<Attribute> attributes) {
    if (!attributes.isEmpty()) {
        StringBuilder sb = new StringBuilder();
        for (Attribute attr : attributes) {
            if (sb.length() > 0) {
                sb.append(", ");
            }
            sb.append(attr.name());
        }
        switch (nativeFileSystemView.getUnsupportedAttributePolicy()) {
        case Ignore:
            break;
        case Warn:
            LOG.warn("Unsupported attributes: " + sb.toString());
            break;
        case ThrowException:
            throw new UnsupportedOperationException("Unsupported attributes: " + sb.toString());
        }
    }
}

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