I'm developing java code that needs to simulate the following:
my_command < file.txt
I tested writing to STDIN but it doesn't seem to be the solution.
Has someone already developed it?
Note, in the below code,
source is an instance of java.io.File
String commandLine = "myCommand";
Process process = Runtime.getRuntime().exec(commandLine);
new Thread(() -> {
try (BufferedWriter stdin = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
Scanner scanner = new Scanner(source)
){
String line;
while (scanner.hasNext()) {
line = scanner.nextLine();
stdin.write(line);
System.out.print(line);
}
stdin.flush();
} catch (IOException e) {
e.printStackTrace();
}
}).start();
int ret = process.waitFor();
FYI my command is mysql
You should use class ProcessBuilder (rather than class Runtime).
I don't know what your my_command is, so the below code uses cleartool.
First I create the text file containing the cleartool subcommands that I wish to execute.
hostinfo
exit
(Note the empty last line of the file.)
I named this file exits_ct.txt
Now the java code that will run cleartool command, then enter the subcommands from the text file and print the command output to standard output.
import java.io.File;
import java.io.IOException;
public class PrcBldTs {
public static void main(String[] args) {
ProcessBuilder pb = new ProcessBuilder("cleartool");
pb.redirectInput(new File("exits_ct.txt"));
pb.redirectOutput(ProcessBuilder.Redirect.INHERIT);
pb.redirectError(ProcessBuilder.Redirect.INHERIT);
try {
Process proc = pb.start(); // throws java.io.IOException
int result = proc.waitFor(); // throws java.lang.InterruptedException
System.out.println("result: " + result);
}
catch (IOException | InterruptedException x) {
x.printStackTrace();
}
}
}
When I run the above code, I get the following output:
MY_COMP: ClearCase 9.0.0.0 (Windows NT 6.2 (build 9200) Pentium)
result: 0
I have a SQL script which I would like to execute from a Java class, running on Windows. I am currently trying to do this using ProcessBuilder in the following function:
public static boolean runSqlScript(String filename, String user, String password) {
ProcessBuilder pb = new ProcessBuilder("mysql", "-u"+user, "-p"+password, "< "+ filename);
try {
Process pr = pb.start();
BufferedReader errors = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
BufferedReader output = new BufferedReader(new InputStreamReader(pr.getInputStream()));
while (pr.isAlive()) {
try {
System.err.println(errors.readLine());
System.out.println(output.readLine());
Thread.sleep(10);
} catch (InterruptedException e) {
break;
}
}
System.err.println(errors.readLine());
System.out.println(output.readLine());
int status = pr.exitValue();
return (status == 0);
} catch (IOException e) {
System.err.println("Error running command: " + e.getMessage());
return false;
}
}
The filename is the absolute path to the script, and the user and password are verified correct. But when I run this, I get the error:
ERROR 1102 (42000): Incorrect database name '< c:/path/to/script.sql'
Why is it interpreting that as a database name rather than a command line argument? Can I use ProcessBuilder to run the script like this?
You need to add database name and it will work ProcessBuilder pb =
new ProcessBuilder("cmd", "/c", "mysql", "-u"+user, "-p"+password,"dbname", " < "+ filename);
Runtime.exec() can also be used to send commands, which doesn't seem to have the same issue as ProcessBuilder:
public static boolean runSqlScriptRuntime(String filename, String user, String password) {
Runtime rt = Runtime.getRuntime();
try {
String cmd = "cmd /c mysql -u " + user + " -p" + password + " < " + filename;
System.out.println(cmd);
Process pr = rt.exec(cmd);
BufferedReader errors = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
BufferedReader output = new BufferedReader(new InputStreamReader(pr.getInputStream()));
while (pr.isAlive()) {
try {
System.err.println(errors.readLine());
System.out.println(output.readLine());
Thread.sleep(10);
} catch (InterruptedException e) {
break;
}
}
System.err.println(errors.readLine());
System.out.println(output.readLine());
int status = pr.exitValue();
return (status == 0);
} catch (IOException e) {
System.err.println("Error running command: " + e.getMessage());
return false;
}
}
An alternative to trying to simulate command-line arguments is to call the SQL script from inside mysql, as described here.
public static boolean runSqlScript(String filename, String user, String password) {
ProcessBuilder pb = new ProcessBuilder("mysql", "-u"+user, "-p"+password);
try {
Process pr = pb.start();
BufferedReader errors = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
BufferedReader output = new BufferedReader(new InputStreamReader(pr.getInputStream()));
BufferedWriter input = new BufferedWriter(new OutputStreamWriter(pr.getOutputStream()));
input.write("source " + filename + ";");
input.flush();
input.write("quit;");
input.flush();
input.close();
while (pr.isAlive()) {
try {
System.err.println(errors.readLine());
System.out.println(output.readLine());
Thread.sleep(10);
} catch (InterruptedException e) {
break;
}
}
System.err.println(errors.readLine());
System.out.println(output.readLine());
int status = pr.exitValue();
return (status == 0);
} catch (IOException e) {
System.err.println("Error running command: " + e.getMessage());
return false;
}
}
This will run MySQL and then call the script. However, I originally was using ProcessBuilder because I thought the script could be handled in a single command line - with a solution like this, it probably makes more sense to just use JDBC.
This might be an easy one - but it's driving me nuts at this point. I'm trying to run SoX from Processing which on my mac computer is running smoothly and with no problems. I need to migrate the code to a windows 7 machine but can't get it to work for some reason. Talking to the terminal from processing works fine. I'm in the right folder (sketch data folder where SoX is also intalled) since I can run commands like "dir" etc. and get the right content printed - but as soon as I try to run sox.exe nothing happens (getting an exit value 1). Running sox.exe straight from the cmd terminal works fine. Here is a sample of what I'm trying to do:
void playBackYear (){
soxPlay = "cmd /c sox.exe year.wav -d";
println (soxPlay);
try {
File workingDir = new File(sketchPath("data"));
Process p=Runtime.getRuntime().exec(soxPlay, null, workingDir);
p.waitFor();
BufferedReader reader=new BufferedReader(
new InputStreamReader(p.getInputStream())
);
String line;
while ( (line = reader.readLine ()) != null)
{
println(line);
}
int exitVal = p.waitFor();
System.out.println("Exited with error code "+exitVal);
}
catch(IOException e1) {
System.err.println("Caught IOException: " + e1.getMessage());
System.out.println( "error 1" );
}
catch(InterruptedException e2) {
System.err.println("Caught IOException: " + e2.getMessage());
System.out.println( "error 2" );
}
}
So the questions is what am I doing wrong here?
Any help is appreciated.
I have written a small wrapper application that wraps sox binary in java. If you are interested in the full project, check it out on GitHub: sox java wrapper project
This is, how i have solved the problem:
private List<String> arguments = new ArrayList<String>();
// add sox arguments to this list above
public void execute() throws IOException {
File soxBinary = new File(soXBinaryPath);
if (!soxBinary.exists()) {
throw new FileNotFoundException("Sox binary is not available under the following path: " + soXBinaryPath);
}
arguments.add(0, soXBinaryPath);
logger.debug("Sox arguments: {}", arguments);
ProcessBuilder processBuilder = new ProcessBuilder(arguments);
processBuilder.redirectErrorStream(true);
Process process = null;
IOException errorDuringExecution = null;
try {
process = processBuilder.start();
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
logger.debug(line);
}
} catch (IOException e) {
errorDuringExecution = e;
logger.error("Error while running Sox. {}", e.getMessage());
} finally {
arguments.clear();
if (process != null) {
process.destroy();
}
if (errorDuringExecution != null) {
throw errorDuringExecution;
}
}
}
It is quite simple to run a Unix command from Java.
Runtime.getRuntime().exec(myCommand);
But is it possible to run a Unix shell script from Java code? If yes, would it be a good practice to run a shell script from within Java code?
You should really look at Process Builder. It is really built for this kind of thing.
ProcessBuilder pb = new ProcessBuilder("myshellScript.sh", "myArg1", "myArg2");
Map<String, String> env = pb.environment();
env.put("VAR1", "myValue");
env.remove("OTHERVAR");
env.put("VAR2", env.get("VAR1") + "suffix");
pb.directory(new File("myDir"));
Process p = pb.start();
You can use Apache Commons exec library also.
Example :
package testShellScript;
import java.io.IOException;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;
public class TestScript {
int iExitValue;
String sCommandString;
public void runScript(String command){
sCommandString = command;
CommandLine oCmdLine = CommandLine.parse(sCommandString);
DefaultExecutor oDefaultExecutor = new DefaultExecutor();
oDefaultExecutor.setExitValue(0);
try {
iExitValue = oDefaultExecutor.execute(oCmdLine);
} catch (ExecuteException e) {
System.err.println("Execution failed.");
e.printStackTrace();
} catch (IOException e) {
System.err.println("permission denied.");
e.printStackTrace();
}
}
public static void main(String args[]){
TestScript testScript = new TestScript();
testScript.runScript("sh /root/Desktop/testScript.sh");
}
}
For further reference, An example is given on Apache Doc also.
I think you have answered your own question with
Runtime.getRuntime().exec(myShellScript);
As to whether it is good practice... what are you trying to do with a shell script that you cannot do with Java?
I would say that it is not in the spirit of Java to run a shell script from Java. Java is meant to be cross platform, and running a shell script would limit its use to just UNIX.
With that said, it's definitely possible to run a shell script from within Java. You'd use exactly the same syntax you listed (I haven't tried it myself, but try executing the shell script directly, and if that doesn't work, execute the shell itself, passing the script in as a command line parameter).
Yes it is possible to do so. This worked out for me.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import org.omg.CORBA.portable.InputStream;
public static void readBashScript() {
try {
Process proc = Runtime.getRuntime().exec("/home/destino/workspace/JavaProject/listing.sh /"); //Whatever you want to execute
BufferedReader read = new BufferedReader(new InputStreamReader(
proc.getInputStream()));
try {
proc.waitFor();
} catch (InterruptedException e) {
System.out.println(e.getMessage());
}
while (read.ready()) {
System.out.println(read.readLine());
}
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
Here is my example. Hope it make sense.
public static void excuteCommand(String filePath) throws IOException{
File file = new File(filePath);
if(!file.isFile()){
throw new IllegalArgumentException("The file " + filePath + " does not exist");
}
if(isLinux()){
Runtime.getRuntime().exec(new String[] {"/bin/sh", "-c", filePath}, null);
}else if(isWindows()){
Runtime.getRuntime().exec("cmd /c start " + filePath);
}
}
public static boolean isLinux(){
String os = System.getProperty("os.name");
return os.toLowerCase().indexOf("linux") >= 0;
}
public static boolean isWindows(){
String os = System.getProperty("os.name");
return os.toLowerCase().indexOf("windows") >= 0;
}
Yes, it is possible and you have answered it! About good practises, I think it is better to launch commands from files and not directly from your code. So you have to make Java execute the list of commands (or one command) in an existing .bat, .sh , .ksh ... files.
Here is an example of executing a list of commands in a file MyFile.sh:
String[] cmd = { "sh", "MyFile.sh", "\pathOfTheFile"};
Runtime.getRuntime().exec(cmd);
To avoid having to hardcode an absolute path, you can use the following method that will find and execute your script if it is in your root directory.
public static void runScript() throws IOException, InterruptedException {
ProcessBuilder processBuilder = new ProcessBuilder("./nameOfScript.sh");
//Sets the source and destination for subprocess standard I/O to be the same as those of the current Java process.
processBuilder.inheritIO();
Process process = processBuilder.start();
int exitValue = process.waitFor();
if (exitValue != 0) {
// check for errors
new BufferedInputStream(process.getErrorStream());
throw new RuntimeException("execution of script failed!");
}
}
As for me all things must be simple.
For running script just need to execute
new ProcessBuilder("pathToYourShellScript").start();
The ZT Process Executor library is an alternative to Apache Commons Exec. It has functionality to run commands, capturing their output, setting timeouts, etc.
I have not used it yet, but it looks reasonably well-documented.
An example from the documentation: Executing a command, pumping the stderr to a logger, returning the output as UTF8 string.
String output = new ProcessExecutor().command("java", "-version")
.redirectError(Slf4jStream.of(getClass()).asInfo())
.readOutput(true).execute()
.outputUTF8();
Its documentation lists the following advantages over Commons Exec:
Improved handling of streams
Reading/writing to streams
Redirecting stderr to stdout
Improved handling of timeouts
Improved checking of exit codes
Improved API
One liners for quite complex use cases
One liners to get process output into a String
Access to the Process object available
Support for async processes ( Future )
Improved logging with SLF4J API
Support for multiple processes
This is a late answer. However, I thought of putting the struggle I had to bear to get a shell script to be executed from a Spring-Boot application for future developers.
I was working in Spring-Boot and I was not able to find the file to be executed from my Java application and it was throwing FileNotFoundFoundException. I had to keep the file in the resources directory and had to set the file to be scanned in pom.xml while the application was being started like the following.
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
<includes>
<include>**/*.xml</include>
<include>**/*.properties</include>
<include>**/*.sh</include>
</includes>
</resource>
</resources>
After that I was having trouble executing the file and it was returning error code = 13, Permission Denied. Then I had to make the file executable by running this command - chmod u+x myShellScript.sh
Finally, I could execute the file using the following code snippet.
public void runScript() {
ProcessBuilder pb = new ProcessBuilder("src/main/resources/myFile.sh");
try {
Process p;
p = pb.start();
} catch (IOException e) {
e.printStackTrace();
}
}
Hope that solves someone's problem.
Here is an example how to run an Unix bash or Windows bat/cmd script from Java. Arguments can be passed on the script and output received from the script. The method accepts arbitrary number of arguments.
public static void runScript(String path, String... args) {
try {
String[] cmd = new String[args.length + 1];
cmd[0] = path;
int count = 0;
for (String s : args) {
cmd[++count] = args[count - 1];
}
Process process = Runtime.getRuntime().exec(cmd);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
try {
process.waitFor();
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
while (bufferedReader.ready()) {
System.out.println("Received from script: " + bufferedReader.readLine());
}
} catch (Exception ex) {
System.out.println(ex.getMessage());
System.exit(1);
}
}
When running on Unix/Linux, the path must be Unix-like (with '/' as separator), when running on Windows - use '\'. Hier is an example of a bash script (test.sh) that receives arbitrary number of arguments and doubles every argument:
#!/bin/bash
counter=0
while [ $# -gt 0 ]
do
echo argument $((counter +=1)): $1
echo doubling argument $((counter)): $(($1+$1))
shift
done
When calling
runScript("path_to_script/test.sh", "1", "2")
on Unix/Linux, the output is:
Received from script: argument 1: 1
Received from script: doubling argument 1: 2
Received from script: argument 2: 2
Received from script: doubling argument 2: 4
Hier is a simple cmd Windows script test.cmd that counts number of input arguments:
#echo off
set a=0
for %%x in (%*) do Set /A a+=1
echo %a% arguments received
When calling the script on Windows
runScript("path_to_script\\test.cmd", "1", "2", "3")
The output is
Received from script: 3 arguments received
It is possible, just exec it as any other program. Just make sure your script has the proper #! (she-bang) line as the first line of the script, and make sure there are execute permissions on the file.
For example, if it is a bash script put #!/bin/bash at the top of the script, also chmod +x .
Also as for if it's good practice, no it's not, especially for Java, but if it saves you a lot of time porting a large script over, and you're not getting paid extra to do it ;) save your time, exec the script, and put the porting to Java on your long-term todo list.
I think with
System.getProperty("os.name");
Checking the operating system on can manage the shell/bash scrips if such are supported.
if there is need to make the code portable.
String scriptName = PATH+"/myScript.sh";
String commands[] = new String[]{scriptName,"myArg1", "myArg2"};
Runtime rt = Runtime.getRuntime();
Process process = null;
try{
process = rt.exec(commands);
process.waitFor();
}catch(Exception e){
e.printStackTrace();
}
Just the same thing that Solaris 5.10 it works like this ./batchstart.sh there is a trick I don´t know if your OS accept it use \\. batchstart.sh instead. This double slash may help.
for linux use
public static void runShell(String directory, String command, String[] args, Map<String, String> environment)
{
try
{
if(directory.trim().equals(""))
directory = "/";
String[] cmd = new String[args.length + 1];
cmd[0] = command;
int count = 1;
for(String s : args)
{
cmd[count] = s;
count++;
}
ProcessBuilder pb = new ProcessBuilder(cmd);
Map<String, String> env = pb.environment();
for(String s : environment.keySet())
env.put(s, environment.get(s));
pb.directory(new File(directory));
Process process = pb.start();
BufferedReader inputReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
BufferedWriter outputReader = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
BufferedReader errReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
int exitValue = process.waitFor();
if(exitValue != 0) // has errors
{
while(errReader.ready())
{
LogClass.log("ErrShell: " + errReader.readLine(), LogClass.LogMode.LogAll);
}
}
else
{
while(inputReader.ready())
{
LogClass.log("Shell Result : " + inputReader.readLine(), LogClass.LogMode.LogAll);
}
}
}
catch(Exception e)
{
LogClass.log("Err: RunShell, " + e.toString(), LogClass.LogMode.LogAll);
}
}
public static void runShell(String path, String command, String[] args)
{
try
{
String[] cmd = new String[args.length + 1];
if(!path.trim().isEmpty())
cmd[0] = path + "/" + command;
else
cmd[0] = command;
int count = 1;
for(String s : args)
{
cmd[count] = s;
count++;
}
Process process = Runtime.getRuntime().exec(cmd);
BufferedReader inputReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
BufferedWriter outputReader = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
BufferedReader errReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
int exitValue = process.waitFor();
if(exitValue != 0) // has errors
{
while(errReader.ready())
{
LogClass.log("ErrShell: " + errReader.readLine(), LogClass.LogMode.LogAll);
}
}
else
{
while(inputReader.ready())
{
LogClass.log("Shell Result: " + inputReader.readLine(), LogClass.LogMode.LogAll);
}
}
}
catch(Exception e)
{
LogClass.log("Err: RunShell, " + e.toString(), LogClass.LogMode.LogAll);
}
}
and for usage;
ShellAssistance.runShell("", "pg_dump", new String[]{"-U", "aliAdmin", "-f", "/home/Backup.sql", "StoresAssistanceDB"});
OR
ShellAssistance.runShell("", "pg_dump", new String[]{"-U", "aliAdmin", "-f", "/home/Backup.sql", "StoresAssistanceDB"}, new Hashmap<>());