Use or not leading slash in value for @RequestMapping. Need official docs or point to Spring source?

Question

I involved in project where I found a mix of:

@RequestMapping(value = \"events/...\");
@RequestMapping(value = \"/events/...\");

(with and without slas

Answer 1

It does not matter: If the path does not start with an / then Spring (DefaultAnnotationHandlerMapping) will add it.

See method String[] determineUrlsForHandler(String beanName) of Class DefaultAnnotationHandlerMapping line 122 (Spring 3.1.2) (that is for the class level)

String[] methodLevelPatterns = determineUrlsForHandlerMethods(handlerType, true);
for (String typeLevelPattern : typeLevelPatterns) {
    if (!typeLevelPattern.startsWith("/")) {
            typeLevelPattern = "/" + typeLevelPattern;
    }

See method String[] determineUrlsForHandler(Class<?> handlerType, final boolean hasTypeLevelMapping)) of Class DefaultAnnotationHandlerMapping line 182 (Spring 3.1.2) (that is for the method level)

String[] mappedPatterns = mapping.value();
if (mappedPatterns.length > 0) {
for (String mappedPattern : mappedPatterns) {
    if (!hasTypeLevelMapping && !mappedPattern.startsWith("/")) {
        mappedPattern = "/" + mappedPattern;
    }