java如何用cmd命令

互联网 20-8-19

java如何用cmd命令的方法：1、使用Runtime中【exec(String command)】方法执行cmd命令；2、先将执行的cmd命令写入到文件中后再执行，这是如果执行错误日志可以打印，线程也不会卡死。

【相关学习推荐：java基础教程】

java如何用cmd命令的方法：

1.使用Runtime中exec(String command)方法执行cmd命令，如下：

Process p = Runtime.getRuntime().exec(cmd);

此方法会抛出IOException，但是在项目中遇到没有出现异常，命令也没有执行的情况。

2.此方法可以达到大多的cmd调用的期望结果，但有些时候回出现命令卡死在p.waitFor();上，造成线程阻塞

public static boolean runCMD(String cmd) throws IOException, InterruptedException {         final String METHOD_NAME = "runCMD";         Process p = Runtime.getRuntime().exec(cmd);         BufferedReader br = null;         try {             br = new BufferedReader(new InputStreamReader(p.getErrorStream()));             String readLine = br.readLine();             StringBuilder builder = new StringBuilder();             while (readLine != null) {                 readLine = br.readLine();                 builder.append(readLine);             }             logger.debug(METHOD_NAME + "#readLine: " + builder.toString());             p.waitFor();             int i = p.exitValue();             logger.info(METHOD_NAME + "#exitValue = " + i);             if (i == 0) {                 return true;             } else {                 return false;             }         } catch (IOException e) {             logger.error(METHOD_NAME + "#ErrMsg=" + e.getMessage());             e.printStackTrace();             throw e;         } finally {             if (br != null) {                 br.close();             }         }     }

3.使用以下方法不会出现和2一样情况下得阻塞的问题，与2的区别就是获取流不同，将getErrorStream换成getInputStream就好了

public static boolean runCMD(String cmd) throws IOException, InterruptedException {         final String METHOD_NAME = "runCMD";                  // Process p = Runtime.getRuntime().exec("cmd.exe /C " + cmd);         Process p = Runtime.getRuntime().exec(cmd);         BufferedReader br = null;         try {             // br = new BufferedReader(new InputStreamReader(p.getErrorStream()));             br = new BufferedReader(new InputStreamReader(p.getInputStream()));             String readLine = br.readLine();             StringBuilder builder = new StringBuilder();             while (readLine != null) {                 readLine = br.readLine();                 builder.append(readLine);             }             logger.debug(METHOD_NAME + "#readLine: " + builder.toString());             p.waitFor();             int i = p.exitValue();             logger.info(METHOD_NAME + "#exitValue = " + i);             if (i == 0) {                 return true;             } else {                 return false;             }         } catch (IOException e) {             logger.error(METHOD_NAME + "#ErrMsg=" + e.getMessage());             e.printStackTrace();             throw e;         } finally {             if (br != null) {                 br.close();             }         }     }

4.对于3方法有个缺点是执行错误时无法将错误消息打印出来，还有一个方法是先将执行的cmd命令写入到文件中后再执行，这是如果执行错误日志可以打印，线程也不会卡死。

　　a.将执行的命名写入到文件中。FileUtils.java

  public static boolean writeFile(File exportFile, final String content) {         if (exportFile == null || StringUtils.isEmpty(content)) {             return false;         }         if (!exportFile.exists()) {             try {                 exportFile.getParentFile().mkdirs();                 exportFile.createNewFile();             } catch (IOException e) {                 e.printStackTrace();                 logger.error("create local json file exception: " + e.getMessage());                 return false;             }         }         BufferedWriter bufferedWriter = null;         try {             FileOutputStream os = new FileOutputStream(exportFile);             FileDescriptor fd = os.getFD();             bufferedWriter = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));             bufferedWriter.write(content);             //Flush the data from the streams and writes into system buffers             //The data may or may not be written to disk.             bufferedWriter.flush();             //block until the system buffers have been written to disk.             //After this method returns, the data is guaranteed to have             //been written to disk.             fd.sync();         } catch (UnsupportedEncodingException e) {             logger.error("saveDBData#catch an UnsupportedEncodingException (" + e.getMessage() + ")");             return false;         } catch (FileNotFoundException e) {             logger.error("saveDBData#catch an FileNotFoundException (" + e.getMessage() + ")");             return false;         } catch (IOException e) {             logger.error("saveDBData#catch an IOException (" + e.getMessage() + ")");             return false;         } catch (Exception e) {             logger.error("saveDBData#catch an exception (" + e.getMessage() + ")");             return false;         } finally {             try {                 if (bufferedWriter != null) {                     bufferedWriter.close();                     bufferedWriter = null;                 }             } catch (IOException e) {                 logger.error("writeJsonToFile#catch an exception (" + e.getMessage() + ")");             }         }         return true;     }

　　b.执行命令

    public static boolean excuteCMDBatFile(String cmd) {         final String METHOD_NAME = "excuteCMDBatFile#";         boolean result = true;         Process p;         File batFile = new File("D:/test/cmd.bat");         System.out.println(batFile.getAbsolutePath());         boolean isSuccess = FileUtils.writeFile(batFile, cmd);         if(!isSuccess) {             logger.error(METHOD_NAME + "write cmd to File failed.");             return false;         }                  String batFilePath = "\"" + MigrateContants.CMD_BAT_FILE + "\"";         logger.info("cmd path:" + batFilePath);         try {             p = Runtime.getRuntime().exec(batFilePath);             InputStream fis = p.getErrorStream();//p.getInputStream();             InputStreamReader isr = new InputStreamReader(fis, System.getProperty("file.encoding"));             BufferedReader br = new BufferedReader(isr);             String line = null;             StringBuilder builder = new StringBuilder();             while ((line = br.readLine()) != null) {                 builder.append(line);             }                          p.waitFor();             int i = p.exitValue();             logger.info(METHOD_NAME + "exitValue = " + i);             if (i != 0) {                 result = false;                 logger.error(METHOD_NAME + "excute cmd failed, [result = " + result + ", error message = " + builder.toString() + "]");                 System.out.println(METHOD_NAME + "excute cmd failed, [result = " + result + ", error message = " + builder.toString() + "]");             }else {                 // logger.debug(METHOD_NAME + "excute cmd result = " + result);                 System.out.println(METHOD_NAME + "result = " + result);             }         } catch (Exception e) {             result = false;             e.printStackTrace();             logger.error(METHOD_NAME + "fail to excute bat File [ErrMsg=" + e.getMessage() + "]");         }         return result;     }