java如何用cmd指令

java如何用cmd指令的方法：1、使用Runtime中【exec(String command)】方法執行cmd指令；2、先將執行的cmd指令寫入檔案後再執行，這是如果執行錯誤日誌可以列印，則執行緒也不會卡死。

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java如何用cmd指令的方法：

1.使用Runtime中exec(String command)方法執行cmd指令，如下：

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

此方法會拋出IOException，但在專案中遇到沒有出現異常，命令也沒有執行的情況。

2.此方法可以達到大多的cmd呼叫的期望結果，但有些時候回出現指令卡死在p.waitFor();上，造成執行緒阻塞

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.使用以下方法不會出現和2一樣情況下得阻塞的問題，與2的區別就是獲取流不同，將getErrorStream換成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.對於3方法有個缺點是執行錯誤時無法將錯誤訊息列印出來，還有一個方法是先將執行的cmd指令寫入到檔案中後再執行，這是如果執行錯誤日誌可以列印，執行緒也不會卡死。

　　a.將執行的命名寫入到檔案中。 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.執行指令

    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;
    }

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