默认值 ${变量:默认值}

			
@Value("${server.name:Windows}") 如果application.properties没有配置server.name那么默认值将是 Windows
private String name;
				
@Value("${some.key:my default value}")
private String stringWithDefaultValue;
			
@Value("${some.key:true}")
private boolean booleanWithDefaultValue;

@Value("${some.key:42}")
private int intWithDefaultValue;			

@Value("${some.key:one,two,three}")
private String[] stringArrayWithDefaults;
 
@Value("${some.key:1,2,3}")
private int[] intArrayWithDefaults;

// Using SpEL
@Value("#{systemProperties['some.key'] ?: 'my default system property value'}")
private String spelWithDefaultValue;
			
		

Null 默认值

			
	@Value("${app.name:@null}") // app.name = null
 	private String name;