@ModelAttribute批注，何时使用？

您不需要仅使用Bean作为参数的

@ModelAttribute

例如，这些处理程序方法可以很好地处理以下请求：

@RequestMapping("/a")void pathA(SomeBean someBean) {  assertEquals("neil", someBean.getName());}GET /a?name=neil@RequestMapping(value="/a", method=RequestMethod.POST)void pathAPost(SomeBean someBean) {  assertEquals("neil", someBean.getName());}POST /aname=neil

使用

@ModelAttribute

@SessionAttributes

Controller

ControllerAdvice

@Controller@RequestMapping("/foos")public class FooController {  @ModelAttribute("foo")  String getFoo() {    return "bar";  // set modelMap["foo"] = "bar" on every request  }}

由

FooController

${foo} //=bar

要么

@ControllerAdvicepublic class MyGlobalData {  @ModelAttribute("foo")  String getFoo() {    return "bar";  // set modelMap["foo"] = "bar" on every request  }}

任何JSP：

${foo} //=bar

如果要使用（ 方法* ）的结果作为 默认值， 请使用

@ModelAttribute

@ModelAttribute

@ModelAttribute("attrib1")SomeBean getSomeBean() {  return new SomeBean("neil");  // set modelMap["attrib1"] = SomeBean("neil") on every request}@RequestMapping("/a")void pathA(@ModelAttribute("attrib1") SomeBean someBean) {  assertEquals("neil", someBean.getName());}GET /a

使用

@ModelAttribute

@RequestMapping("/a")String pathA(RedirectAttributes redirectAttributes) {  redirectAttributes.addFlashAttribute("attrib1", new SomeBean("from flash"));  return "redirect:/b";}@RequestMapping("/b")void pathB(@ModelAttribute("attrib1") SomeBean someBean) {  assertEquals("from flash", someBean.getName());}GET /a

使用

@ModelAttribute

@SessionAttributes

@Controller@SessionAttributes("attrib1")public class Controller1 {    @RequestMapping("/a")    void pathA(Model model) {        model.addAttribute("attrib1", new SomeBean("neil")); //this ends up in session due to @SessionAttributes on controller    }    @RequestMapping("/b")    void pathB(@ModelAttribute("attrib1") SomeBean someBean) {        assertEquals("neil", someBean.getName());    }}GET /aGET /b