Spring Boot bind @Value to Enum case insensitive

Question

Enum

public enum Property {
    A,
    AB,
    ABC;
}

Field

@Value("${custom.property}")
protected Property property;

application.properties (lower case)

custom.property=abc

When I'm running application I have an error:

Cannot convert value of type [java.lang.String] to required type [com.xxx.Property]: no matching editors or conversion strategy found.

Whereas (upper case):

custom.property=ABC

Works fine.

Is there a way to bind the value case insensitive? Like ABC, Abc, AbC, abc any pattern should work.

NOTE: I saw this question - Spring 3.0 MVC binding Enums Case Sensitive but in my case I have over 10 enums/values (and expect to have more) classes and to implement 10 different custom property binders would be painful, I need some generic solution.

Looks like a potential bug with relaxed binding. – chrylis -cautiouslyoptimistic- Feb 22 '16 at 23:12 — chrylis -cautiouslyoptimistic-, Feb 22 '16 at 23:12
Sorry, edited description. Value's case switched. – Mikhail Kholodkov Feb 22 '16 at 23:16 — Mikhail Kholodkov, Feb 22 '16 at 23:16

Stephane Nicoll · Accepted Answer · 2016-02-24T08:40:21.763

32

@Value and @ConfigurationProperties features do not match. I couldn't stress enough how @ConfigurationProperties is superior.

First, you get to design your configuration in a simple POJO that you can inject wherever you want (rather than having expressions in annotation that you can easily break with a typo). Second, the meta-data support means that you can very easily get auto-completion in your IDE for your own keys.

And finally, the relaxed binding described in the doc only applies to @ConfigurationProperties. @Value is a Spring Framework feature and is unaware of relaxed binding. We intend to make that more clear in the doc.

TL;DR abc works with @ConfigurationProperties but won't with @Value.

edited Feb 24 '16 at 08:40

answered Feb 23 '16 at 08:02

Stephane Nicoll

31,977
9
97
89

Makes sense. Thanks! – Mikhail Kholodkov Feb 24 '16 at 03:26
@Stephane Nicoll What is the recommendation for Spring 4.? – userit1985 Jun 19 '17 at 16:09
1

@Stephane Nicoll I thought the relaxed binding has to do with the key. I'm not sure where it is made clear that enum names in the value part will be mapped case-insensitively. It is pretty convenient though. – rougou Jan 29 '20 at 09:59

score 8 · Answer 2 · answered Dec 17 '18 at 07:49

A problem with ConfigurationPropertis (afaik) is that you cannot use constructor injection, and your class has to be mutable.

A workaround (or hack if you like) would be to use SpEL to uppercase the property before looking it up, like this:

@Value("#{'${custom.property}'.toUpperCase()}") Property property

This should work since enums instances are constants, and should always be defined in uppercase: https://docs.oracle.com/javase/tutorial/java/javaOO/enum.html

score 2 · Answer 3 · answered Jul 31 '23 at 13:44

Another option is setter injection:

protected Property property;

@Autowired
public void setProperty(@Value("${custom.property}") String propertyString) {
  this.property = Property.valueOf(propertyString.toUpperCase())
}

It is more verbose than SpEL but it allows you to do more complicated processing

You could also combine SpEL with a custom parsing function:

package com.example.enums

public enum Property {
  A,
  AB,
  ABC;

  public static Property parse(String name) {
    // you can do more complicated processing here
    return valueOf(name.toUpperCase());
  }

}

@Value("#( T(com.example.enums.Property).parse('${custom.property}') )")
protected Property property;

jonny.l · Answer 4 · 2017-08-30T10:24:55.547

-12

In a practical world, this works....

public enum Property {
    A, a
    AB, ab,
    ABC, abc,
    ABCD, abcd,
    ABCDE, abcde; 

    public boolean isA() {
        return this.equals(A) || this.equals(a);
    }

    public boolean isAB() {
        return this.equals(AB) || this.equals(ab);
    }

    ...etc...

}

..although this does break the principle of the enum!

edited Aug 30 '17 at 10:24

answered Aug 30 '17 at 08:20

jonny.l

105
1
11

Spring Boot bind @Value to Enum case insensitive

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