• DI method
• Factory

• @RequestMapping
• Autowiring Controller Services
• URI template
• Method arguments, ex: HttpSession, HttpServletRequest

• Single object

Parameter's names mapping to Model's properties name

• Composite objects, ex: One product belongs to a category
• Binding lists, ex: One person has a list of contacts (One-many relationship)

• Option 1: build list items of attribute in controller method

List<String> checks = new LinkedList<>(Array.asList(new String[]{
   "Lead Time", "Special Rate", "Requires Approval"
}));
model.addAttribute("checkOptions", checks);

• Option 2: Use annotation @ModelAttribute

@ModelAttribute("checkOptions")
public List<String> getChecks(){
   return new LinkedList<>(Array.asList(new String[]{
      "Lead Time", "Special Rate", "Requires Approval"
   }));
}

Use this option, we need to define model attribute only. When a request sent, all model attributes are populated for the model.

Allow we decide which model's attributes will be copied to HttpSession before render the view

@Controller
@SessionAttributes("myModelAttribute")
public class MyController {
   //...
   @ModelAttribute("myModelAttribute")
   public MyModel getMyModel(){
       //...
   }
}

The session attribute is removed only when sessionStatus.setComplete() was called

@RequestMapping(method = RequestMethod.POST)
public void doSomething(@ModelAttribute("myModel") MyModel model, SessionStatus sessionStatus){
   //...
   sessionStatus.setComplete();
}

• @ResponseBody: method returned value will be written to the http response automatically.
• @RequestBody: incoming request body will be converted to the parameter object.
  • HttpMessageConverter is used to convert request body string to parameter object. The string can be a serialized JSON object.

@RequestMapping("/request")
@ResponseBody
public String request(@RequestBody Resource resource) {
    System.out.println(resource);
    // Send out an email for request
    return "The request has been sent for approval";
}

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>

 <form:form method="post" modelAttribute="userForm" action="${userActionUrl}">
 	<form:input path="name" type="text" /> <!-- bind to user.name-->
 	<form:errors path="name" />
 </form:form>

Handling exceptions in specific handler classes or methods

  @ExceptionHandler(Exception.class)
  public String handleError(HttpServletRequest req) {
     return "controller_error";
  }

• Create a class that implements HandlerExceptionResolver

View name resolution is configurable through:

• File extension
• Accept header content type
• Bean names
• A properties file
• Custom ViewResolver implementation

View Resolvers