commons-exec执行系统命令

有些场景下需要在java中执行Bat命令或者Shell命令，如使用wkhtmltopdf生成pdf报表等，这时可以借助apache的commons-exec，指定ExecuteWatchdog 可以完整控制整个执行声明周期，不会产生失控进程。

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-exec</artifactId>
            <version>1.3</version>
        </dependency>
           

/**
     * 执行不需要返回结果的命令
     * @throws Exception
     */
     public void execCmdWithoutResult() throws Exception{
         //开启windows telnet: net start telnet
         //注意：第一个空格之后的所有参数都为参数
        CommandLine cmdLine = new CommandLine("net");
        cmdLine.addArgument("start");
        cmdLine.addArgument("telnet");
        DefaultExecutor executor = new DefaultExecutor();
        executor.setExitValue(1);
        //设置60秒超时，执行超过60秒后会直接终止
        ExecuteWatchdog watchdog = new ExecuteWatchdog(60 * 1000);
        executor.setWatchdog(watchdog);
        DefaultExecuteResultHandler handler = new DefaultExecuteResultHandler();
        executor.execute(cmdLine, handler);
        //命令执行返回前一直阻塞
        handler.waitFor();
    }

    /**
     * 带返回结果的命令执行
     * @return
     */
    private String execCmdWithResult() {
        try {
            String command = "ping 192.168.1.10";
            //接收正常结果流
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            //接收异常结果流
            ByteArrayOutputStream errorStream = new ByteArrayOutputStream();
            CommandLine commandline = CommandLine.parse(command);
            DefaultExecutor exec = new DefaultExecutor();
            exec.setExitValues(null);
            //设置一分钟超时
            ExecuteWatchdog watchdog = new ExecuteWatchdog(60*1000);
            exec.setWatchdog(watchdog);
            PumpStreamHandler streamHandler = new PumpStreamHandler(outputStream,errorStream);
            exec.setStreamHandler(streamHandler);
            exec.execute(commandline);
            //不同操作系统注意编码，否则结果乱码
            String out = outputStream.toString("GBK");
            String error = errorStream.toString("GBK");
            return out+error;
        } catch (Exception e) {
            e.printStackTrace();
            return e.getMessage();
        }
    }