从 yaml 文件中读取整数列表

Question

The current implementation is :-

public static final List<Integer> validCodes = Collections.unmodifiableList(Arrays.asList(110, 210, 310,510,610));

However, I am not happy with this approach as this of hard coded. I want to make it configurable instead of hard-coded. I suppose reading this values from the yaml file would solve my problem.

But how do I define a list of Integer in the yaml file and real it using @value. I can find a lot of example about reading list of strings but not integers.

Answer 1

Within the application.yml file, define the config variable as follows.

my_integers: 1231,12323,12321

then use the @Value annotation to make to an Integer list as follows.

@Value("#{'${my_integers}'.split(',')}")
private List<Integer> myIntegers;

Spring does the rest. You only need to use myIntegers with your need. Happy coding....

PS: I have used spring boot 2.0.*

Answer 2

One way:

Let's say if the properties file contains

intArr={1,2,3}

Then @Value can be used like:

@Value("#{${intArr}}")
Integer[] intArr;

Second way:

If the property contains comma separated values as: intArr: [1, 2, 3]

Then the annotation code would be:

@Value("${intArr}")
private int[] intArr;

Edit:

You can configure ConversionServiceFactoryBean which activates the new configuration service which supports converting String to Collection types.

By activating this, it will support following kind of conversion:

 intArray= 1, 2, 3, 4

And the following code:

@Value("${intArray}")
private List<Integer> myList;

Ref here

Answer 3

You can used following method for getting all available properties from YML file. When you used following method, you have to add following jar into your build script.

compile group: 'org.yaml', name: 'snakeyaml', version: '1.12'   

I think this will help you to continue your task.

private Map<String, Object> loadYMLData() {
        Map<String, Object> result = new HashMap<String, Object>();
        try {
            String fileName = "{{YAMAL FILE NAME}}.yml";
            Yaml yaml = new Yaml();
            ClassLoader classLoader = getClass().getClassLoader();
            File file = new File(classLoader.getResource(fileName).getFile());
            InputStream ios = new FileInputStream(file);

            // Parse the YAML file and return the output as a series of Maps and Lists
            result = (Map<String, Object>) yaml.load(ios);
            System.out.println(result.toString());

        } catch (Exception e) {
            logger.error("Error==>", e);
        }
        return result;
    }