小编典典
在等待命令完成的同时,必须连续读取输出。否则,如果命令产生足够的输出以填充输出缓冲区,则该命令将挂起,等待缓冲区被消耗,这将永远不会发生。这样您就陷入僵局。
以下示例在监视命令状态的同时连续读取stdout和stderr。它基于官方的JSch
exec.java示例(仅添加了stderr的阅读)。
ChannelExec channel = (ChannelExec)session.openChannel("exec");
channel.setCommand(
"for((i=1;i<=10000;i+=2)); do echo \"Long output - $i\"; done ; " +
"echo error output >&2");
InputStream commandOutput = channel.getExtInputStream();
StringBuilder outputBuffer = new StringBuilder();
StringBuilder errorBuffer = new StringBuilder();
InputStream in = channel.getInputStream();
InputStream err = channel.getExtInputStream();
channel.connect();
byte[] tmp = new byte[1024];
while (true) {
while (in.available() > 0) {
int i = in.read(tmp, 0, 1024);
if (i < 0) break;
outputBuffer.append(new String(tmp, 0, i));
}
while (err.available() > 0) {
int i = err.read(tmp, 0, 1024);
if (i < 0) break;
errorBuffer.append(new String(tmp, 0, i));
}
if (channel.isClosed()) {
if ((in.available() > 0) || (err.available() > 0)) continue;
System.out.println("exit-status: " + channel.getExitStatus());
break;
}
try {
Thread.sleep(1000);
} catch (Exception ee) {
}
}
System.out.println("output: " + outputBuffer.toString());
System.out.println("error: " + errorBuffer.toString());
channel.disconnect();
如果在while (!channel.isClosed()) {}之后添加channel.connect();,您会看到ishell
for循环中有足够大的空间(在我的环境中,10000就足够了),循环永远不会结束。
2020-09-09