需要做一個監控遠端Linux磁盤空間的東西,絞盡腦汁終于發現一個東西。ch.ethz.ssh2。
它可以通過使用者名和密碼登入可以ssh登入的機器,并且可以執行指令,并将指令顯示的東西傳回來。
上代碼了:
Connection con = null;
Session session = null;
BufferedReader dr = null;
try {
String ipd = mc.getIpAddress();
if(ipd.equals("127.0.0.1")){
con = new Connection(mc.getIpAddress(),2222);
}else{
con = new Connection(mc.getIpAddress());
}
ConnectionInfo info = con.connect();
boolean result = con.authenticateWithPassword(mc.getUserName(), mc.getPassword());
session = con.openSession();
session.execCommand("df -T");
InputStream stdout = session.getStdout();
stdout = new StreamGobbler(session.getStdout());
dr = new BufferedReader(new InputStreamReader(stdout));
String line;
while ((line=dr.readLine()) != null) {
System.out.println(line);
if(line.startsWith("/dev/")){
Pattern p = Pattern.compile("[\\s]+");
String[] arrs = p.split(line);
for (String s : arrs) {
System.out.println(s);
}
if(!arrs[1].startsWith("iso")){
if(Long.parseLong(arrs[4])<5L*1024*1024 || Double.parseDouble(arrs[5])>0.9d){
doAfterThing(mc, arrs[0]);
}
}
}
}
} catch (Exception e) {
System.err.println(e.getMessage());
} finally {
try {
dr.close();
session.close();
con.close();
} catch (Exception e) {
e.printStackTrace();
}
}
要注意的地方有兩點:
1.
Connection con = new Connection(String ip);
接收一個遠端位址做參數,預設端口是22。如果不是這個端口,需要指定。比如我用的虛拟機,使用了端口轉發,是以寫成
Connection con = new Connection(mc.getIpAddress(),2222);
因為的端口是2222.
2.session.getStdout() 的傳回值是一個InputStream,但是需要包裝後才能用。
剛開始我寫成了
InputStream stdout = session.getStdout();
dr = new BufferedReader(new InputStreamReader(stdout));
怎麼也娶不到東西。
後來寫為
InputStream stdout = new StreamGobbler(session.getStdout());
才好了。StreamGobbler是ch.ethz.ssh2自己的一個類,文檔如下:
/**
* A <code>StreamGobbler</code> is an InputStream that uses an internal worker
* thread to constantly consume input from another InputStream. It uses a buffer
* to store the consumed data. The buffer size is automatically adjusted, if needed.
*/
=========================================另外補充一點Java檢視本地磁盤資訊的方法:
這也是在查找過程中找到的。
File[] roots = File.listRoots();
System.err.println("the count of roots is : "+roots.length);
double constm = 1024 * 1024 * 1024 ;
double total = 0d;
for (File _file : roots) {
System.out.println(_file.getPath());
double total0 = _file.getTotalSpace()/constm,free0=_file.getFreeSpace()/constm,used0=total0-free0;
System.out.println("totol space = " + total0+" G");
System.out.print("the free space = " + free0+" G");
System.out.println("---------- "+free0*100/total0+"% ----------");
System.out.print("the used space = " + used0+" G");
System.out.println("---------- "+used0*100/total0+"% ----------");
System.out.println();
total+=_file.getTotalSpace();
}
System.out.println("the total space of the machine = "+doubleFormat(total/constm));
代碼很簡單,不過有一點要注意:getTotalSpace()獲得的是這個盤的總容量,getFreeSpace()獲得的是剩餘容量,還有個方法是getUsableSpace(),這個并不表示已經用了多少,而是磁盤可用空間。通常情況下,這個值和剩餘容量是相等的。