Java运行系统命令

之前写过一个版本的Java代码用来调用linux shell脚本，原文如下：

http://blog.csdn.net/sheismylife/article/details/4817851

不过没有试过windows下运行，试了一下，还是不错的，把代码做了一些调整，封装成对象，这样更方便多线程下调用，不用担心静态变量互相干扰的问题。

先看一下怎么用：

    public static void main(String[] args) {        try {            Command command = new Command();            CommandResult result1 = command.exec("net stop nginx", 20000);            System.out.println("command executiion succeeds: " + result1.getOutput());            CommandResult result2 = command.exec("net start nginx", 20000);            System.out.println("command executiion succeeds: " + result2.getOutput());        } catch (CommandError ex) {            System.out.println("command execution failed: " + ex.getMessage());        }    }

由此可见，有三个类：Command, CommandResult和CommandError。

当命令不能运行，将会抛出CommandError异常对象。如果命令能够运行，不管是否成功或者失败，都返回CommandResult对象，里面有两个属性output和error，包含了执行成功的消息和错误消息。

CommandError.java代码：

package command;/** * * @author shu6889 */public class CommandError extends Exception {    /**     * Creates a new instance of     * <code>CommandError</code> without detail message.     */    public CommandError() {    }    /**     * Constructs an instance of     * <code>CommandError</code> with the specified detail message.     *     * @param msg the detail message.     */    public CommandError(String msg) {        super(msg);    }        public CommandError(Throwable ex) {        super(ex);    }}

CommandResult.java代码

package command;/*** Describe class CommandResult here.**/public class CommandResult { public static final int EXIT_VALUE_TIMEOUT=-1;        private String output;    void setOutput(String error) {        output=error;    }    public 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;    }}

最重要的Command.java代码：

package command;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;/** * Describe class Command here. * */public class Command {    private long startTime;    private long timeout;    private static final long INTERVAL = 500;    /*     * command is one system command represented by string     * timeout is milliseconds for waiting the command execution     * throw CommandError if the system command can't be executed     * return CommandResult when the system command is executed no matter what the command returns(succeed or failed)     */    public CommandResult exec(final String command, long timeout) throws CommandError {        this.timeout = timeout;        try {            Process process = Runtime.getRuntime().exec(command);            CommandResult result = wait(process);            if (process != null) {                process.destroy();            }            return result;        } catch (Exception ex) {            throw new CommandError(ex);        }    }    private boolean isTimeout() {        return System.currentTimeMillis() - startTime >= timeout;    }    private CommandResult wait(final 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            startTime = System.currentTimeMillis();            boolean isFinished = false;            for (;;) {                if (isTimeout()) {                    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());                    }                    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(INTERVAL);                }            }        } finally {            if (errorStreamReader != null) {                try {                    errorStreamReader.close();                } catch (IOException e) {                }            }            if (inputStreamReader != null) {                try {                    inputStreamReader.close();                } catch (IOException e) {                }            }        }    }}