Is it possible to read console input just before the embedded tomcat on the spring boot starts? The supposedly application flow is, request username and password from the user, and that will be used to be able to start the application. It works when using the java -jar command, the problem is when I close the console(SSH on linux) the process stops. I tried searching about it and found out that the process is tied to the console, so I tried using nohup, the problem is I cannot request for console input when using that. Is there any other way?
4 Answers
Answers 1
I think this can help you.
public static void main(String[] args) { Scanner scanner = new Scanner(System.in); // prompt for the user's name System.out.print("Enter your name: "); // get their input as a String String username = scanner.next(); System.out.println(username); SpringApplication.run(Application.class, args); } Answers 2
You can use nohup to start the jar with the parameters, they just won't be prompted for them on new lines in the terminal. The User could add them as parameters when starting the jar. See details below.
Example:
Main Class
public static void main(String[] args) { String username = args[0]; String password = args[1]; if(username.equals("admin") && password.equals("password")) { SpringApplication.run(NohupApplication.class, args); } else { System.out.println("You are not authorized to start this application."); } } With Invalid Credentials
Command
nohup java -jar example.jar user password nohup.out
You are not authorized to start this application. With Valid Credentials
Command
nohup java -jar example.jar admin password nohup.out
. ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v1.5.2.RELEASE) Answers 3
Get username and password in shell script before executing your java program and pass those as argument to your application.
#!/bin/bash # Ask login details read -p 'user: ' uservar read -sp 'password: ' passvar echo Now you have user and password you can run java command with nohup and pass user password as jvm properties. You can also pass user and password as program arguments as suggested in other answer.
Like nohup java -jar abc.jar -Duser=$user -Dpassword=$password
And fetch these properties using
String user = System.getProperty("String"); String password = System.getProperty("password"); Answers 4
If you want to full log with console input like logger + System.out.println() outputs, then you have to use
nohup java -jar yourJarFile.jar admin password >> fullLogOutput.log & Another issue:
the problem is when I close the console(SSH on linux) the process stops.
So you want to run your jar file as background process. You can't stop it with your console closing. Just add & symbol after full command, it will not stop. You can use the following command.
nohup java -jar yourJarFile.jar & For taking full log with console output
nohup java -jar yourJarFile.jar >> fullLogOutput.log & The & symbol is used to run the program in the background.
The nohup utility makes the command passed as an argument run in the background even after you log out.
Stopping/Killing the back-end process:
For stopping the background process, use ps -aux to get the id and then kill (id number)
ps -aux | grep yourJarFile.jar You will get the id number. To kill that
sudo kill -9 <pid> Resource Link: http://stackoverflow.com/a/12108646/2293534
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