commons-exec執行系統指令

有些場景下需要在java中執行Bat指令或者Shell指令，如使用wkhtmltopdf生成pdf報表等，這時可以借助apache的commons-exec，指定ExecuteWatchdog 可以完整控制整個執行聲明周期，不會産生失控程序。

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

/**
     * 執行不需要傳回結果的指令
     * @throws Exception
     */
     public void execCmdWithoutResult() throws Exception{
         //開啟windows telnet: net start telnet
         //注意：第一個空格之後的所有參數都為參數
        CommandLine cmdLine = new CommandLine("net");
        cmdLine.addArgument("start");
        cmdLine.addArgument("telnet");
        DefaultExecutor executor = new DefaultExecutor();
        executor.setExitValue(1);
        //設定60秒逾時，執行超過60秒後會直接終止
        ExecuteWatchdog watchdog = new ExecuteWatchdog(60 * 1000);
        executor.setWatchdog(watchdog);
        DefaultExecuteResultHandler handler = new DefaultExecuteResultHandler();
        executor.execute(cmdLine, handler);
        //指令執行傳回前一直阻塞
        handler.waitFor();
    }

    /**
     * 帶傳回結果的指令執行
     * @return
     */
    private String execCmdWithResult() {
        try {
            String command = "ping 192.168.1.10";
            //接收正常結果流
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            //接收異常結果流
            ByteArrayOutputStream errorStream = new ByteArrayOutputStream();
            CommandLine commandline = CommandLine.parse(command);
            DefaultExecutor exec = new DefaultExecutor();
            exec.setExitValues(null);
            //設定一分鐘逾時
            ExecuteWatchdog watchdog = new ExecuteWatchdog(60*1000);
            exec.setWatchdog(watchdog);
            PumpStreamHandler streamHandler = new PumpStreamHandler(outputStream,errorStream);
            exec.setStreamHandler(streamHandler);
            exec.execute(commandline);
            //不同作業系統注意編碼，否則結果亂碼
            String out = outputStream.toString("GBK");
            String error = errorStream.toString("GBK");
            return out+error;
        } catch (Exception e) {
            e.printStackTrace();
            return e.getMessage();
        }
    }