Spring4中的控制器缓存不起作用

Question

When I write the following code the cache doesn't work

@Cacheable("books")
@RequestMapping(method = RequestMethod.GET)
public String list(Model model) {
    System.out.println("Retrieving products");
    model.addAttribute("products", productDao.list());
    return "products/list";
}

But if I write the following the cache works

@Cacheable("books")
@RequestMapping(method = RequestMethod.GET)
public ModelAndView list() {
    ModelAndView modelAndView = new ModelAndView("products/list");
    System.out.println("Retrieving products");
    modelAndView.addObject("products", productDao.list());
    return modelAndView;
}

Can someone tell why the first code doesn't cache?

Answer 1

I guess I found the answer. Due to the argument, as the object can be different each time it's called, most of the time the value will be not equal.

Therefore, the cache will understand it as a different request and will not bring the cached value.