Run cmd commands through Java
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
How to execute cmd commands through java
You can try below code
Process process = Runtime.getRuntime().exec("cmd /c start cmd.exe /K java -jar selenium-server-standalone-2.44.0.jar -role hub");
However this will run executable jar from your current directory, where you .class file exist.
How to execute cmd commands via Java
The code you posted starts three different processes each with it's own command. To open a command prompt and then run a command try the following (never tried it myself):
try {
// Execute command
String command = "cmd /c start cmd.exe";
Process child = Runtime.getRuntime().exec(command);
// Get output stream to write from it
OutputStream out = child.getOutputStream();
out.write("cd C:/ /r/n".getBytes());
out.flush();
out.write("dir /r/n".getBytes());
out.close();
} catch (IOException e) {
}
How to execute cmd command in Java class?
what's the problem with this code. It's perfectly working. opens and shows content of the file 111.txt
try {
String str ="C:/uploaded_files/111.txt";
Process process = Runtime.getRuntime().exec(new String[]{"cmd.exe", "/c",str});
System.out.println(str);
} catch (Exception ex) {}
please check whether the path is correct and whether the directories and files are not missed or spelled
Running Command Line in Java
Runtime rt = Runtime.getRuntime();
Process pr = rt.exec("java -jar map.jar time.rel test.txt debug");
http://docs.oracle.com/javase/7/docs/api/java/lang/Runtime.html
Execute CMD command through JSP file
Method exec
(in class java.lang.Runtime
) does not serve as the equivalent of a command prompt window. The method arguments are the name of an executable that you wish to run – which in your case is schtasks – together with any options required by that command. Again, in your case the command options are:
/query /tn "\\dummy\\file" /v /fo list
However, as stated in the javadoc for class java.lang.Process
As of 1.5,
ProcessBuilder.start()
is the preferred way to create aProcess
.
Therefore you should rather use class java.lang.ProcessBuilder.
Also, since you are launching the command from Java code, you should use Java code to handle the output of the schtasks
command.
The below code is a stand-alone, console application that demonstrates executing schtasks
, locating the Last Run Time
line from the command output and saving that line in a file.
Note that if file schtasks.exe
is not in any of the folders of the System
property java.library.path
then you need to supply the full path to schtasks.exe
.
(More notes after the code.)
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
public class SchTasks {
public static void main(String args[]) {
ProcessBuilder pb = new ProcessBuilder("schtasks.exe",
"/QUERY",
"/FO",
"LIST",
"/V",
"/TN",
"\\dummy\\file");
String result = null;
try {
Process p = pb.start(); // throws java.io.IOException
BufferedReader out = p.inputReader();
String output = out.readLine();
while (output != null) {
if (output.startsWith("Last Run Time:")) {
result = output;
}
output = out.readLine();
}
int status = p.waitFor(); // throws java.lang.InterruptedException
if (status == 0 && result != null) {
try (PrintWriter pw = new PrintWriter("C:\\Users\\me\\Desktop\\lastRunTime.txt")) {
pw.println(result);
}
}
}
catch (InterruptedException | IOException x) {
x.printStackTrace();
}
}
}
- Method
inputReader
was added to classProcess
in JDK 17 so if you are using an earlier version, you can use method getInputStream instead.
Here are the contents of file lastRunTime.txt
after I ran the above code.
Last Run Time: 30/11/1999 00:00:00
I assume that you actually need to do something with the actual last run time (of task \\dummy\\file
) so rather than save it to a file, you can convert it to a timestamp in Java code. The below code replaces the part of the above code that saves the result to a file.
if (status == 0 && result != null) {
String[] parts = result.split(":\\s{2,}", 2);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss",
Locale.ENGLISH);
LocalDateTime lastRunTime = LocalDateTime.parse(parts[1], formatter);
System.out.println("Last Run Time: " + lastRunTime);
}
Refer to the following:
- javadoc for method split (in class
java.lang.String
) - Regular Expressions lesson in Oracle's Java tutorials.
- Date Time trail in Oracle's Java tutorials.
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