Spring MVC redirect with variables - spring

Question

I have following Spring MVC 3.2.4 method:
#RequestMapping(value = "/products/{product}", method = RequestMethod.POST)
public String update(Product product, #Valid #ModelAttribute("productForm") ProductForm productForm, BindingResult bindingResult, Model model) {
if (bindingResult.hasErrors()) {
return "products/view";
}
mapper.map(productForm, product);
productService.saveProduct(product);
return "redirect:/products/{product}";
}
After success it should redirect back user to detail of product. Problem is that instead of redirecting to page "/products/1" I am redirected to page "/products/Product [code=1234567890, name=Nejaky]". It looks like placeholder {product} is replaced by product.toString() instead of original ID from URL.
I am using built-in Spring Data converter:
<mvc:annotation-driven conversion-service="conversionService">
<mvc:argument-resolvers>
<bean class="org.springframework.data.web.PageableHandlerMethodArgumentResolver" />
</mvc:argument-resolvers>
</mvc:annotation-driven>
<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean" />
<bean class="org.springframework.data.repository.support.DomainClassConverter">
<constructor-arg ref="conversionService" />
</bean>
What should I do to make it work correctly and redirect me back to "/products/1" without doing things like "redirect:/product" + product.getId()?

Answer 1

Our story starts in RedirectView source code, in the method replaceUriTemplateVariables.
protected StringBuilder replaceUriTemplateVariables(
String targetUrl, Map<String, Object> model, Map<String, String> currentUriVariables, String encodingScheme)
throws UnsupportedEncodingException {
StringBuilder result = new StringBuilder();
Matcher m = URI_TEMPLATE_VARIABLE_PATTERN.matcher(targetUrl);
int endLastMatch = 0;
while (m.find()) {
String name = m.group(1);
Object value = model.containsKey(name) ? model.remove(name) : currentUriVariables.get(name);
Assert.notNull(value, "Model has no value for '" + name + "'");
result.append(targetUrl.substring(endLastMatch, m.start()));
result.append(UriUtils.encodePathSegment(value.toString(), encodingScheme));
endLastMatch = m.end();
}
result.append(targetUrl.substring(endLastMatch, targetUrl.length()));
return result;
}
As you had predicted, the method uses value.toString() where value is your product object in the Model. No other component like a conversion system is involved here. Your options are as follows:
Use
"redirect:/product" + product.getId()
Add a model attribute called "productId" and use that in your view name
model.addAttribute("productId", product.getId());
"redirect:/product/{productId}"
Or use uri variables. I don't have information on those yet.

Answer 2

Ok, finally found reason for this. I had to annotate product param with #PathVariable. Wondering that it worked without it.

Answer 3

I know it's an old question but for anyone facing the same problem here is the answer
Just inject RedirectAttributes to your controller and use redirectAtrr.addAttribute([attrbuteName],[attributeValue])
#RequestMapping(value = "/products/{product}", method = RequestMethod.POST)
public String update(Product product,#Valid,#ModelAttribute("productForm") ProductForm productForm,BindingResult bindingResult,Model model,RedirectAttributes redirectAttr) {
if (bindingResult.hasErrors()) {
return "products/view";
}
mapper.map(productForm, product);
productService.saveProduct(product);
redirectAttr.addAttributte("productId",product.getId());
return "redirect:/products/{productId}";
}
Read documentation for more understanding.