Primitive Types

Values such as int and boolean can be declared with defaults.

@Value("${taeng.test:1}")
private int value;

@Value("${taeng.test:true}")
private boolean value;

One important caveat is type casting failure. For example, the following code throws an exception and the application does not start. TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'int'; nested exception is java.lang.NumberFormatException: For input string: "true"

@Value("${taeng.test:true}")
private int value;

String

If no value exists for taeng.test, the string defaultMsg is used as the default.

@Value("${taeng.test:defaultMsg}")
private String msg;

You can also set an empty string as the default value.

@Value("${taeng.test:}")
private String msg;

For reference, if you omit :, the property must exist. Otherwise an exception occurs. (Could not resolve placeholder 'taeng.test' in value "${taeng.test}")

Array

You can assign default values to arrays as well. Separate items with commas.

@Value("${taeng.test:1,2,3}")
private int[] values;

@Value("${taeng.test:a,b,c}")
private String[] values;

SpEL (Spring Expression Language)

You can also set defaults in Spring Expression Language (SpEL). If the java.home system property does not exist, the string hello is used as the default.

@Value("#{systemProperties['java.home'] ?: 'hello'}")
private String values;