I found several code snippets for running cmd commands through a Java class, but I wasn't able to understand it.
This is code for opening the cmd
public void excCommand(String new_dir){
Runtime rt = Runtime.getRuntime();
try {
rt.exec(new String[]{"cmd.exe","/c","start"});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
And I found some other links for adding other commands such as cd
http://www.coderanch.com/t/109753/Linux-UNIX/exec-command-cd-command-java
How to open the command prompt and insert commands using Java?
Can anyone help me to understand how to cd a directory such as:
cd C:\Program Files\Flowella
then run other commands on that directory?
One way to run a process from a different directory to the working directory of your Java program is to change directory and then run the process in the same command line. You can do this by getting cmd.exe to run a command line such as cd some_directory && some_program.
The following example changes to a different directory and runs dir from there. Admittedly, I could just dir that directory without needing to cd to it, but this is only an example:
import java.io.*;
public class CmdTest {
public static void main(String[] args) throws Exception {
ProcessBuilder builder = new ProcessBuilder(
"cmd.exe", "/c", "cd \"C:\\Program Files\\Microsoft SQL Server\" && dir");
builder.redirectErrorStream(true);
Process p = builder.start();
BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
while (true) {
line = r.readLine();
if (line == null) { break; }
System.out.println(line);
}
}
}
Note also that I'm using a ProcessBuilder to run the command. Amongst other things, this allows me to redirect the process's standard error into its standard output, by calling redirectErrorStream(true). Doing so gives me only one stream to read from.
This gives me the following output on my machine:
C:\Users\Luke\StackOverflow>java CmdTest
Volume in drive C is Windows7
Volume Serial Number is D8F0-C934
Directory of C:\Program Files\Microsoft SQL Server
29/07/2011 11:03 <DIR> .
29/07/2011 11:03 <DIR> ..
21/01/2011 20:37 <DIR> 100
21/01/2011 20:35 <DIR> 80
21/01/2011 20:35 <DIR> 90
21/01/2011 20:39 <DIR> MSSQL10_50.SQLEXPRESS
0 File(s) 0 bytes
6 Dir(s) 209,496,424,448 bytes free
You can try this:-
Process p = Runtime.getRuntime().exec(command);
If you want to perform actions like cd, then use:
String[] command = {command_to_be_executed, arg1, arg2};
ProcessBuilder builder = new ProcessBuilder(command);
builder = builder.directory(new File("directory_location"));
Example:
String[] command = {"ls", "-al"};
ProcessBuilder builder = new ProcessBuilder(command);
builder = builder.directory(new File("/ngs/app/abc"));
Process p = builder.start();
It is important that you split the command and all arguments in separate strings of the string array (otherwise they will not be provided correctly by the ProcessBuilder API).
Here is a more complete implementation of command line execution.
Usage
executeCommand("ls");
Output:
12/27/2017 11:18:11:732: ls
12/27/2017 11:18:11:820: build.gradle
12/27/2017 11:18:11:820: gradle
12/27/2017 11:18:11:820: gradlew
12/27/2017 11:18:11:820: gradlew.bat
12/27/2017 11:18:11:820: out
12/27/2017 11:18:11:820: settings.gradle
12/27/2017 11:18:11:820: src
Code
private void executeCommand(String command) {
try {
log(command);
Process process = Runtime.getRuntime().exec(command);
logOutput(process.getInputStream(), "");
logOutput(process.getErrorStream(), "Error: ");
process.waitFor();
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
}
private void logOutput(InputStream inputStream, String prefix) {
new Thread(() -> {
Scanner scanner = new Scanner(inputStream, "UTF-8");
while (scanner.hasNextLine()) {
synchronized (this) {
log(prefix + scanner.nextLine());
}
}
scanner.close();
}).start();
}
private static SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy hh:mm:ss:SSS");
private synchronized void log(String message) {
System.out.println(format.format(new Date()) + ": " + message);
}
My example (from real project)
folder — File.
zipFile, filesString — String;
final String command = "/bin/tar -xvf " + zipFile + " " + filesString;
logger.info("Start unzipping: {} into the folder {}", command, folder.getPath());
final Runtime r = Runtime.getRuntime();
final Process p = r.exec(command, null, folder);
final int returnCode = p.waitFor();
if (logger.isWarnEnabled()) {
final BufferedReader is = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
while ((line = is.readLine()) != null) {
logger.warn(line);
}
final BufferedReader is2 = new BufferedReader(new InputStreamReader(p.getErrorStream()));
while ((line = is2.readLine()) != null) {
logger.warn(line);
}
}
The easiest way would be to use Runtime.getRuntime.exec().
For example, to get a registry value for the default browser on Windows:
String command = "REG QUERY HKEY_CLASSES_ROOT\\http\\shell\\open\\command";
try
{
Process process = Runtime.getRuntime().exec(command);
} catch (IOException e)
{
e.printStackTrace();
}
Then use a Scanner to get the output of the command, if necessary.
Scanner kb = new Scanner(process.getInputStream());
Note: the \ is an escape character in a String, and must be escaped to work properly (hence the \\).
However, there is no executable called cd, because it can't be implemented in a separate process.
The one case where the current working directory matters is executing an external process (using ProcessBuilder or Runtime.exec()). In those cases you can specify the working directory to use for the newly started process explicitly.
Easiest way for your command:
System.setProperty("user.dir", "C:\\Program Files\\Flowella");
Try this:
Process runtime = Runtime.getRuntime().exec("cmd /c start notepad++.exe");
Once you get the reference to Process, you can call getOutpuStream on it to get the standard input of the cmd prompt. Then you can send any command over the stream using write method as with any other stream.
Note that it is process.getOutputStream() which is connected to the stdin on the spawned process. Similarly, to get the output of any command, you will need to call getInputStream and then read over this as any other input stream.
Stopping and Disabling a service can be done via below code:
static void sdService() {
String[] cmd = {"cmd.exe", "/c", "net", "stop", "MSSQLSERVER"};
try {
Process process = new ProcessBuilder(cmd).start();
process.waitFor();
String line = null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
line = null;
bufferedReader = null;
Process p = Runtime.getRuntime().exec("sc config MSSQLSERVER start= disabled");
p.waitFor();
bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
Enabling and Starting a service can be done via below code
static void esService() {
String[] cmd = {"cmd.exe", "/c", "net", "start", "MSSQLSERVER"};
try {
Process p = Runtime.getRuntime().exec("sc config MSSQLSERVER start= auto");
//Process p = Runtime.getRuntime().exec("sc config MSSQLSERVER start= demand");
p.waitFor();
String line = null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
line = null;
bufferedReader = null;
Process process = new ProcessBuilder(cmd).start();
process.waitFor();
bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
Executing command from any folder can be done via below code.
static void runFromSpecificFolder() {
try {
ProcessBuilder processBuilder = new ProcessBuilder("cmd.exe", "/c", "cd \"C:\\Users\\himan\\Desktop\\Java_Test_Deployment\\jarfiles\" && dir");
//processBuilder.directory(new File("C://Users//himan//Desktop//Java_Test_Deployment//jarfiles"));
processBuilder.redirectErrorStream(true);
Process p = processBuilder.start();
p.waitFor();
String line = null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String args[]) {
sdService();
runFromSpecificFolder();
esService();
}
You can't run cd this way, because cd isn't a real program; it's a built-in part of the command-line, and all it does is change the command-line's environment. It doesn't make sense to run it in a subprocess, because then you're changing that subprocess's environment — but that subprocess closes immediately, discarding its environment.
To set the current working directory in your actual Java program, you should write:
System.setProperty("user.dir", "C:\\Program Files\\Flowella");
public class Demo {
public static void main(String args[]) throws IOException {
Process process = Runtime.getRuntime().exec("/Users/******/Library/Android/sdk/platform-tools/adb" + " shell dumpsys battery ");
BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
while (true) {
line = in.readLine();
if (line == null) { break; }
System.out.println(line);
}
}
}
The simplest and shortest way is to use CmdTool library.
new Cmd()
.configuring(new WorkDir("C:/Program Files/Flowella"))
.command("cmd.exe", "/c", "start")
.execute();
You can find more examples here.
one of the way to execute cmd from java !
public void executeCmd() {
String anyCommand="your command";
try {
Process process = Runtime.getRuntime().exec("cmd /c start cmd.exe /K " + anyCommand);
} catch (IOException e) {
e.printStackTrace();
}
}
Here the value adder is use of ampersands to batch commands and correct format for change drive with cd.
public class CmdCommander {
public static void main(String[] args) throws Exception {
//easyway to start native windows command prompt from Intellij
/*
Rules are:
1.baseStart must be dual start
2.first command must not have &.
3.subsequent commands must be prepended with &
4.drive change needs extra &
5.use quotes at start and end of command batch
*/
String startQuote = "\"";
String endQuote = "\"";
//String baseStart_not_taking_commands = " cmd /K start ";
String baseStart = " cmd /K start cmd /K ";//dual start is must
String first_command_chcp = " chcp 1251 ";
String dirList = " &dir ";//& in front of commands after first command means enter
//change drive....to yours
String changeDir = " &cd &I: ";//extra & makes changing drive happen
String javaLaunch = " &java ";//just another command
String javaClass = " Encodes ";//parameter for java needs no &
String javaCommand = javaLaunch + javaClass;
//build batch command
String totalCommand =
baseStart +
startQuote +
first_command_chcp +
//javaCommand +
changeDir +
dirList +
endQuote;
System.out.println(totalCommand);//prints into Intellij terminal
runCmd(totalCommand);
//Thread t = Thread.currentThread();
//t.sleep(3000);
System.out.println("loppu hep");//prints into Intellij terminal
}
public static void runCmd(String command) throws Exception {
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(command);
}
}
Each character should switch between upper and lower case. My issue is that I cannot get it to work properly. This is what I have so far:
oneLine = br.readLine();
while (oneLine != null){ // Until the line is not empty (will be when you reach End of file)
System.out.println (oneLine); // Print it in screen
bw.write(oneLine); // Write the line in the output file
oneLine = br.readLine(); // read the next line
}
int ch;
while ((ch = br.read()) != -1){
if (Character.isUpperCase(ch)){
Character.toLowerCase(ch);
}
bw.write(ch);
}
Here you go. You had a few problems:
You were never actually storing the result of the character case switch.
You needed to save the line return with each row
I broke out the case switch to make it easier to read
Here's the modified code:
public static void main(String args[]) {
String inputfileName = "input.txt"; // A file with some text in it
String outputfileName = "output.txt"; // File created by this program
String oneLine;
try {
// Open the input file
FileReader fr = new FileReader(inputfileName);
BufferedReader br = new BufferedReader(fr);
// Create the output file
FileWriter fw = new FileWriter(outputfileName);
BufferedWriter bw = new BufferedWriter(fw);
// Read the first line
oneLine = br.readLine();
while (oneLine != null) { // Until the line is not empty (will be when you reach End of file)
String switched = switchCase(oneLine); //switch case
System.out.println(oneLine + " > "+switched); // Print it in screen
bw.write(switched+"\n"); // Write the line in the output file
oneLine = br.readLine(); // read the next line
}
// Close the streams
br.close();
bw.close();
} catch (Exception e) {
System.err.println("Error: " + e.getMessage());
}
}
public static String switchCase(String string) {
String r = "";
for (char c : string.toCharArray()) {
if (Character.isUpperCase(c)) {
r += Character.toLowerCase(c);
} else {
r += Character.toUpperCase(c);
}
}
return r;
}
How can I get this program to read in the "lab13.txt" in the command line? I've been trying to figure this out for over an hour and nothing seemed to work.
The prompt is "Write a program that determines and displays the number of lines in the file whose name you specify on the command line. Test your program with lab13.txt."
import java.util.Scanner;
import java.io.*;
class homework
{
public static void main(String[] args) throws IOException
{
Scanner inFile= new Scanner(new File("lab13.txt"));
int count=0;
String s;
while (inFile.hasNextLine())
{
s = inFile.nextLine();
count++;
}
System.out.println(count + " Lines in lab13.txt");
inFile.close();
}
}
If you want the user to be able to input the filename from command line or console in eclipse try using this
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Please enter filename : ");
String filename = null;
try {
filename = reader.readLine();
} catch (IOException e) {
e.printStackTrace();
}
You can then plug the filename into your Scanner object
http://docs.oracle.com/javase/tutorial/essential/environment/cmdLineArgs.html
The stuff you add to the command-line after the program name go in the args array, so:
Scanner inFile= new Scanner(new File(args[0]));
Try this
In your code you need to replace new File("lab13.txt") with new File(args[0])
For command line
public static void main(String[] args) {
File inFile =null;
if (0 < args.length) {
File inFile = new File(args[0]);
}
BufferedReader br = null;
try {
String sCurrentLine;
br = new BufferedReader(new FileReader(inFile));
while ((sCurrentLine = br.readLine()) != null) {
System.out.println(sCurrentLine);
}
}
catch (IOException e) {
e.printStackTrace();
}
finally {
try {
if (br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
For a particular location
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class BufferedReaderExample {
public static void main(String[] args) {
BufferedReader br = null;
try {
String sCurrentLine;
br = new BufferedReader(new FileReader("C:\\lab13.txt"));
while ((sCurrentLine = br.readLine()) != null) {
System.out.println(sCurrentLine);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (isMultipart) {
System.out.println("multipart2");
// Create a factory for disk-based file items
FileItemFactory factory = new DiskFileItemFactory();
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
try {
// Parse the request
List /* FileItem */ items = upload.parseRequest(request);
Iterator iterator = items.iterator();
while (iterator.hasNext()) {
FileItem item = (FileItem) iterator.next();
if (item.isFormField()) //your code for getting form fields
{
if (item.getFieldName().equals("btn")) {
if (item.getString().equals("Submit")) {
String name = item.getFieldName();
String value = item.getString();
System.out.println("test2" + name + value);
}
if (item.getString().equals("Save as Draft")) {
System.out.println("hii hii2");
String name = item.getFieldName();
String value = item.getString();
}
}
} if (!item.isFormField()) {
String fileName = item.getName();
System.out.println("File Upload Named : " + fileName);
String root = getServletContext().getRealPath("/");
File path = new File(root + "/uploads");
if (!path.exists()) {
boolean status = path.mkdirs();
}
File uploadedFile = new File(path + "/" + fileName);
// System.out.println(uploadedFile.getAbsolutePath());
item.write(uploadedFile);
}
}
} catch (FileUploadException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
response.sendRedirect("/EventCalendar-war/pages/user_pages/user_create_event.jsp");
}
This is my code.When there is no file to upload I got java.io.FileNotFoundException .If file is upload with form data it's work fine.What is wrong with my code?
I need help on this one, I am trying to read a text file stored in sdcard and store the result in an ArrayList for subsequent usage, but the code is crashing.
public class Mytextreader extends Activity {
final ArrayList> dataList = new ArrayList>();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
loadData();
String text = "";
for (int i = 0; i < dataList.size(); i++) {
text = text + dataList.get(i).get("name") + ":"
+ dataList.get(i).get("image") + ":"
+ dataList.get(i).get("price") + ":"
+ dataList.get(i).get("barcode") + "\n";
}
TextView txv = (TextView) findViewById(R.id.textView01);
txv.setText(text);
}
private void loadData() {
File sdcardDir = Environment.getExternalStorageDirectory();
String sdcard = sdcardDir.getAbsolutePath();
File file = new File(sdcard + "/Downloads/data/data.txt");
// For each entry the following lines are repeated
HashMap<String, String> hmap = new HashMap<String, String>();
String text = "", line = "";
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(file));
while ((line = br.readLine()) != null) {
text = text + line + "\n";
}
br.close();
} catch (IOException e) {
Log.d("File Read test: Error= ", e.getMessage());
}
while (true) {
line = text.substring(0, text.indexOf('\n'));
text = text.substring(text.indexOf('\n') + 1);
hmap.put("name", line.substring(0, line.indexOf(';')));
line = line.substring(line.indexOf(';') + 1);
// Toast.makeText(this, line, Toast.LENGTH_LONG).show();
hmap.put("image", line.substring(0, line.indexOf(';')));
line = line.substring(line.indexOf(';') + 1);
// Toast.makeText(this, line, Toast.LENGTH_LONG).show();
hmap.put("price", line.substring(0, line.indexOf(';')));
line = line.substring(line.indexOf(';') + 1);
// Toast.makeText(this, line, Toast.LENGTH_LONG).show();
hmap.put("barcode", line);
dataList.add(hmap);
hmap.clear();
if (text.length() == 0)
break;
}
}
}
Ok fixed, the text file has an empty line, removed that line and the code is ok now