using application.properties values to create a SFTP connection

Question

my application.properties file look like this:

sftp.host=0.0.0.0
sftp.port=22
sftp.user=foo
sftp.password=pass

and my upload class with upload method looks like this:

public class UpAndDownLoad {

  @Value("${sftp.host}")
  private String sftpHost;
  @Value("${sftp.port}")
  private int sftpPort;
  @Value("${sftp.user}")
  private String sftpUser;
  @Value("${sftp.password}")
  private String sftpPasword;

  private DefaultSftpSessionFactory getSftpFactory() {
    DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory();
    factory.setHost(sftpHost);
    factory.setPort(sftpPort);
    factory.setAllowUnknownKeys(true);
    factory.setUser(sftpUser);
    factory.setPassword(sftpPasword);
    return factory;
  }

  public void upload() throws IOException {
    SftpSession session = getSftpFactory().getSession();
    InputStream resourceAsStream = UpAndDownLoad.class.getClassLoader().getResourceAsStream("mytextfile.txt");
    session.write(resourceAsStream, "upload/mynewfile" + LocalDateTime.now() + ".txt");
    session.close();
  }

Whenever I type out the values of sftp host, user, password the upload method works meticulously.

  private DefaultSftpSessionFactory getSftpFactory() {
    DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory();
    factory.setHost("0.0.0.0");
    factory.setPort(22);
    factory.setAllowUnknownKeys(true);
    factory.setUser("foo");
    factory.setPassword("passs");
    return factory;
  }

But as soon as i pass in the vlaues from the application properties, like shown at the second code block, it fails with: java.lang.IllegalStateException: failed to create SFTP Session

Answer 1

Simply you modify your applicationContext.xml by this adding <context:property-holder>.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

       <context:property-placeholder location="classpath:application.properties"/>

</beans>

or if Java based Config, then this :

@Configuration
@PropertySource("classpath:application.properties")
public class Config {

}

Make the class as component.

@Component
public class UpAndDownLoad {

  @Value("${sftp.host}")
  private String sftpHost;
  @Value("${sftp.port}")
  private int sftpPort;
  @Value("${sftp.user}")
  private String sftpUser;
  @Value("${sftp.password}")
  private String sftpPasword;

  private DefaultSftpSessionFactory getSftpFactory() {
    DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory();
    factory.setHost(sftpHost);
    factory.setPort(sftpPort);
    factory.setAllowUnknownKeys(true);
    factory.setUser(sftpUser);
    factory.setPassword(sftpPasword);
    return factory;
  }

  public void upload() throws IOException {
    SftpSession session = getSftpFactory().getSession();
    InputStream resourceAsStream = UpAndDownLoad.class.getClassLoader().getResourceAsStream("mytextfile.txt");
    session.write(resourceAsStream, "upload/mynewfile" + LocalDateTime.now() + ".txt");
    session.close();
  }

}