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

javaspringspring-mvc

I involved in project where I found a mix of:

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

(with and without slash before method level annotation).

I perform search:

site:http://static.springsource.org/spring/docs/3.1.x  slash

and read these links:

But none of these sources answer why skipping slash allowed. Official Spring docs always shown examples with slashes…

Need point to official docs or to Spring sources.

Best Answer

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;
    }
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