我正在尝试使用多个线程从远程服务器下载多个文件。但是,当我使用多个线程时,我得到了
java.lang.IOException:管道已关闭。
当我使用一个线程时,相同的代码工作正常。
是否无法使用JSch从同一远程服务器同时下载多个文件?
SftpTest.java
public class SftpTest {
private static List<SftpAccessor> accessorList = new ArrayList<SftpAccessor>();
private static List<Payload> files = new ArrayList<Payload>();
private static ExecutorService writerThreadPool = Executors.newFixedThreadPool(10);
public static void main(String args[]) throws JSchException, InterruptedException {
SSH srcServer = new SSH();
srcServer.setHostname("10.22.65.140");
srcServer.setKey("D:\\jars\\dmwvmcol01.ec2user.pem");
srcServer.setPort("22");
srcServer.setUsername("ec2-user");
SftpAccessor acc = new SftpAccessor(srcServer);
accessorList.add(acc);
files.addAll(acc.ls("/data/test/src", false, "*", 1));
for (Payload file : files) {
writerThreadPool.submit(new LocalWriterThread(file));
}
writerThreadPool.shutdown();
writerThreadPool.awaitTermination(20, TimeUnit.MINUTES);
}}
LocalWriterThread.java
public class LocalWriterThread implements Callable<String> {
private Payload payload;
public LocalWriterThread(Payload payload) {
this.payload = payload;
}
public String call() throws Exception {
String dest = "D:\\output\\jobsystemnew";
System.out.println(payload.getFilename());
File file = new File(dest + "/" + payload.getFilename());
file.createNewFile();
FileOutputStream fos = new FileOutputStream(file);
copy(payload.getInputStream(), fos);
payload.setInputStream(null);
return "";
}
private void copy(InputStream is, OutputStream os) throws IOException {
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try {
System.out.println("Started Copying file : " + payload.getFilename());
bis = new BufferedInputStream(is);
bos = new BufferedOutputStream(os);
byte[] buffer = new byte[1024];
while (bis.read(buffer) != -1) {
bos.write(buffer);
}
bos.flush();
System.out.println("Finished Copying file : " + payload.getFilename());
}
finally {
System.out.println("Closing input stream for " + payload.getFilename());
bis.close();
bos.close();
/*
* try { if (is != null) { is.close(); } } catch (Exception e) { System.out.println(" " + e + " : " + e.getMessage() + " unable to close input stream : " + payload.getFilename());
* e.printStackTrace(); }
*/
/*
* try { if (os != null) { os.close(); } } catch (Exception e) { System.out.println(" " + e + " : " + e.getMessage() + " unable to close output stream : " + payload.getFilename());
* e.printStackTrace(); }
*/
}
}}
SSH.java
public class SSH {
String hostname;
String port;
String username;
String key;
public String getHostname() {
return hostname;
}
public void setHostname(String hostname) {
this.hostname = hostname;
}
public String getPort() {
return port;
}
public void setPort(String port) {
this.port = port;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
} }
SftpAccessor.java
public class SftpAccessor {
private JSch jsch = new JSch();
private ChannelSftp channelSftp = null;
private Session session = null;
String errorMsg = null;
public SftpAccessor(SSH ssh) throws JSchException {
jsch.addIdentity(ssh.getKey());
session = jsch.getSession(ssh.getUsername(), ssh.getHostname(), Integer.parseInt(ssh.getPort()));
session.setHostKeyAlias(ssh.getKey());
java.util.Properties config = new java.util.Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect();
channelSftp = (ChannelSftp) session.openChannel("sftp");
channelSftp.connect();
}
public List<Payload> ls(String directory, boolean recursive, String filemask, int delayMinutes) {
List<Payload> files = new ArrayList<Payload>();
try {
channelSftp.cd(directory);
@SuppressWarnings("unchecked")
Vector<ChannelSftp.LsEntry> entries = channelSftp.ls(filemask);
for (ChannelSftp.LsEntry entry : entries) {
try {
if (entry.getAttrs().isDir()) {
if (recursive) {
List<Payload> filesToAdd = ls(directory + "/" + entry.getFilename(), recursive, filemask, delayMinutes);
files.addAll(filesToAdd);
}
}
else {
Date lastmodified = new Date(entry.getAttrs().getMTime() * 1000L);
Date currdate = new Date(new Date().getTime() - (delayMinutes * 60 * 1000L));
if (lastmodified.before(currdate)) {
String filename = entry.getFilename();
entry.getAttrs().getMTime();
Payload file = new Payload();
System.out.println("Getting input Stream for " + directory + "/" + filename);
file.setInputStream(channelSftp.get(directory + "/" + filename));
file.setFilename(filename);
file.setLastModified(lastmodified);
files.add(file);
}
}
}
catch (Exception e) {
e.printStackTrace();
}
}
}
catch (SftpException e) {
}
return files;
}}
Payload.java
public class Payload {
private String filename;
private InputStream inputStream;
private Date lastModified;
public String getFilename() {
return filename;
}
public void setFilename(String filename) {
this.filename = filename;
}
public Date getLastModified() {
return lastModified;
}
public void setLastModified(Date lastModified) {
this.lastModified = lastModified;
}
public InputStream getInputStream() {
return inputStream;
}
public void setInputStream(InputStream inputStream) {
this.inputStream = inputStream;
}}
答案 0 :(得分:5)
JSch不是线程安全的。即便如此,在单个SSH会话中使用并行下载几乎没有任何性能优势。它会像串行下载一样慢。此外,您可能会遇到并发文件句柄的服务器端限制。
您应该为每个线程/下载打开一个单独的会话。