spring boot: unable to bind yaml list objects

0
votes

I need to bind a list of POJO by yaml properties file but I was no luck to get it work. My application.yml has the following lines:

printer:
  printers:
    - deviceNo: abc
      key: 123

And PrinterProperties like this:

@Component
@ConfigurationProperties(prefix = "printer")
class PrinterProperties {
    var printers: List<Printer> = listOf()
}

But the field printers was not poputated with the application.ymlvalue.

There was a samilar problem

I pushed a demo to a github repository to demostrate this problem.

3
springspring-boot
I converted the POJO from kotlin to java and it works now – Guisong He
@Aymen, re. your suggested edit: Please, Spring Boot is not part of Java EE. It's part of Spring! – BalusC

3 Answers

1
votes

As described in the Spring Boot docs at Externalized Configuration page, you can bind properties like that in your example as long they accomplish one of this conditions:

1) The class property has a setter

2) It's initialized with a mutable value.

listOf() will give you an unmutable value therefore it won't work.

Hope it helped! :)

1
votes

From Andy Wilkinson's advice: the POJO should have a default constructor. So I changed the POJO with:

class Printer {
    var deviceNo: String? = null
    var key: String? = null
}

and it works now.

0
votes
printer:
  printers:
    - 
      deviceNo: abc
      key: 123

Your yaml file should like this.