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);
                }
            }
        }
    }
}