java中cmd命令是什么使用的，方法是什么？
导读：相信很多人对“java中cmd命令是什么使用的，方法是什么？”都不太了解，下面小编为你详细解释一下这个问题，希望对你有一定的帮助 java如何用cmd命令的方法：1、使用Runtime中【exec(Str...
相信很多人对“java中cmd命令是什么使用的，方法是什么？”都不太了解，下面小编为你详细解释一下这个问题，希望对你有一定的帮助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;
}
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