現在通過CommandHelper.execute方法可以執行命令，該類實現
複製代碼 代碼如下:
package javaapplication3;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
/**
*
* @author chenshu
*/
public class CommandHelper {
//default time out, in millseconds
public static int DEFAULT_TIMEOUT;
public static final int DEFAULT_INTERVAL = 1000;
public static long START;
public static CommandResult exec(String command) throws IOException, InterruptedException {
Process process = Runtime.getRuntime().exec(command);
CommandResult commandResult = wait(process);
if (process != null) {
process.destroy();
}
return commandResult;
}
private static boolean isOverTime() {
return System.currentTimeMillis() - START >= DEFAULT_TIMEOUT;
}
private static CommandResult wait(Process process) throws InterruptedException, IOException {
BufferedReader errorStreamReader = null;
BufferedReader inputStreamReader = null;
try {
errorStreamReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
inputStreamReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
//timeout control
START = System.currentTimeMillis();
boolean isFinished = false;
for (;;) {
if (isOverTime()) {
CommandResult result = new CommandResult();
result.setExitValue(CommandResult.EXIT_VALUE_TIMEOUT);
result.setOutput("Command process timeout");
return result;
}
if (isFinished) {
CommandResult result = new CommandResult();
result.setExitValue(process.waitFor());
//parse error info
if (errorStreamReader.ready()) {
StringBuilder buffer = new StringBuilder();
String line;
while ((line = errorStreamReader.readLine()) != null) {
buffer.append(line);
}
result.setError(buffer.toString());
}
//parse info
if (inputStreamReader.ready()) {
StringBuilder buffer = new StringBuilder();
String line;
while ((line = inputStreamReader.readLine()) != null) {
buffer.append(line);
}
result.setOutput(buffer.toString());
}
return result;
}
try {
isFinished = true;
process.exitValue();
} catch (IllegalThreadStateException e) {
// process hasn't finished yet
isFinished = false;
Thread.sleep(DEFAULT_INTERVAL);
}
}
} finally {
if (errorStreamReader != null) {
try {
errorStreamReader.close();
} catch (IOException e) {
}
}
if (inputStreamReader != null) {
try {
inputStreamReader.close();
} catch (IOException e) {
}
}
}
}
}
CommandHelper類使用了CommandResult對象輸出結果錯誤資訊。該類實現
複製代碼 代碼如下:
package javaapplication3;
/**
*
* @author chenshu
*/
public class CommandResult {
public static final int EXIT_VALUE_TIMEOUT=-1;
private String output;
void setOutput(String error) {
output=error;
}
String getOutput(){
return output;
}
int exitValue;
void setExitValue(int value) {
exitValue=value;
}
int getExitValue(){
return exitValue;
}
private String error;
/**
* @return the error
*/
public String getError() {
return error;
}
/**
* @param error the error to set
*/
public void setError(String error) {
this.error = error;
}
}
現在看看調用代碼的示範（main函數接受一個逾時參數）：
複製代碼 代碼如下:
public static void main(String[] args) {
try {
int timeout = Integer.parseInt(args[0]);
CommandHelper.DEFAULT_TIMEOUT = timeout;
CommandResult result = CommandHelper.exec("mkdir testdir");
if (result != null) {
System.out.println("Output:" + result.getOutput());
System.out.println("Error:" + result.getError());
}
} catch (IOException ex) {
System.out.println("IOException:" + ex.getLocalizedMessage());
} catch (InterruptedException ex) {
System.out.println("InterruptedException:" + ex.getLocalizedMessage());
}
}
結果會建立一個testdir目錄。
我嘗試用這種方法建立通過ssh登入到遠程機器，遇到兩個問題：
1）如果希望沒有人機對話方式，則需要使用命令sshpass -p password ssh user@targetIP 'command'
2) 在NetBeans上直接運行工程是不行的，因為許可權不夠,需要在終端裡運行java javaapplication3.Main
3) 很多命令不能運行，只有如pwd等命令可以運行，原因還不清楚，最好改用Ganymed SSH-2庫或者其他類似Java庫，我會在下一篇文章中介紹如何使用。
