java执行shell脚本超时控制

Java的Runtime可以执行命令行脚本，某些特定场合需要对脚本的执行时间进行控制，防止脚本某些异常情况下，一直未能正确结束，导致Java主进程挂起。本文的程序对这一过程进行了控制

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;



public class CommandUtils {
private static Logger logger = LoggerFactory.getLogger(CommandUtils.class);

//default time out, in millseconds
public static final int DEFAULT_TIMEOUT = 10 * 1000;
public static final int DEFAULT_INTERVAL = 1000;

/**
* Executes the specified command in a separate process. The method then blocks until the process returned.
* If an error arises during the execution or if the exeecuted process returned an non-null return code,
* the content of the process' stderr is returned to the caller. If the execution is fine, null is returned.
*
* @param command String
* @return CommandResult
*/
public static CommandResult exec(String command) {
long start = System.currentTimeMillis();
long last;

CommandResult commandResult = new CommandResult();

try {
Process process = Runtime.getRuntime().exec(command);
process(process, commandResult);

if (process != null) {
process.destroy();
}

last = (System.currentTimeMillis() - start) / 1000;
logger.info("Execute command [" + command + "], last [" + last + "] s.");

} catch (Exception e) {
last = (System.currentTimeMillis() - start) / 1000;
String error = "Execute command [" + command + "] last [" + last + "] s, failed [" + e.getMessage() + "]";
logger.error(error, e);

commandResult.setExitValue(CommandResult.EXIT_VALUE_UNEXCEPTED);
commandResult.setErrorOutput(error);
}

return commandResult;
}

private static void process(Process process, CommandResult commandResult) {
BufferedReader errorReader = null;
BufferedReader inputReader = null;

try {
errorReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
inputReader = new BufferedReader(new InputStreamReader(process.getInputStream()));

//timeout control
long start = System.currentTimeMillis();
boolean processFinished = false;

while (System.currentTimeMillis() - start < DEFAULT_TIMEOUT && !processFinished) {
processFinished = true;
try {
process.exitValue();
} catch (IllegalThreadStateException e) {
// process hasn't finished yet
processFinished = false;

try {
Thread.sleep(DEFAULT_INTERVAL);
} catch (InterruptedException e1) {
logger.error("Process, failed [" + e.getMessage() + "]", e);
}
}
}

if (!processFinished) {
commandResult.setExitValue(CommandResult.EXIT_VALUE_TIMEOUT);
commandResult.setErrorOutput("Command process timeout");
return;
}

commandResult.setExitValue(process.waitFor());

StringBuffer sb;
String line;

//parse error info
if (errorReader.ready()) {
sb = new StringBuffer();
while ((line = errorReader.readLine()) != null) {
sb.append(line);
}
commandResult.setErrorOutput(sb.toString());
}

//parse info
if (inputReader.ready()) {
sb = new StringBuffer();
while ((line = inputReader.readLine()) != null) {
sb.append(line);
}
commandResult.setInfoOutput(sb.toString());
}

} catch (Exception e) {
String error = "Command process, failed [" + e.getMessage() + "]";
logger.error(error, e);

commandResult.setExitValue(CommandResult.EXIT_VALUE_UNEXCEPTED);
commandResult.setErrorOutput(error);

} finally {
if (errorReader != null) {
try {
errorReader.close();
} catch (IOException e) {
logger.error("Close BufferedReader, failed [" + e.getMessage() + "]", e);
}
}

if (inputReader != null) {
try {
inputReader.close();
} catch (IOException e) {
logger.error("Close BufferedReader, failed [" + e.getMessage() + "]", e);
}
}
}
}
}