Java運行Shell腳本

利用Runtime.execute方法，我們可以在Java程序中運行Linux的Shell腳本，或者執行其他程序。參考了互聯網上的這篇文章，我重新整理了代碼。
現在通過CommandHelper.execute方法可以執行命令，該類實現代碼如下：
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對象輸出結果錯誤信息。