常用注解元素

@Controller

标注在Bean的类定义处

@RequestMapping

真正让Bean具备Spring MVC Controller功能的是@RequestMapping这个注解

@RequestMapping可以标注在类定义处，将Controller和特定请求关联起来；

还可以标注在方法签名处，以便进一步对请求进行分流

配套的属性有：

value需要跳转的地址

method基于RestFul的跳转参数,有RequestMethod.getpost put delete等

params符合某个参数的时候才调用该方法

Headers符合头信息的时候才调用

@SessionAttributes

将结果放入session内

@ModelAttribute

存储在响应内容ModelMap或者ModelAndView进行保存值传到前台，当如果你需要保存值比较少

的时候可以采用这种方式进行保存值并且保存到前台显示

在默认情况下，ModelMap中的属性作用域是request 级别，相当于HttpServletRequest中的request.setAttribute()一样,在JSP视图页面中通过request.getAttribute(“attribute name”)或者通过

${ attribute name } EL表达式访问模型对象中的属性对象

如果希望在ModelMap 的作用域范围为 session，可以有选择地指定 ModelMap 中的哪些属性需要转存到 session 中，以便下一个请求属对应的 ModelMap 的属性列表中还能访问到这些属性。这一功能是通过类定义处标注 @SessionAttributes 注解来实现 如： 

@Controller

@RequestMapping("/login.do")

@SessionAttributes("currUser")

public class BbtForumController {。。。。。}

@ResponseBody

标注后返回String对象的结果为response内容体，不标注的话作为dispatcher url使用

@PathVariable

允许将请求路径的制定内容当做求情的参数使用

返回类型

请求处理方法入参的可选类型说明

void此时逻辑视图名由请求处理方法对应的URL确定，如以下的方法：

@RequestMapping("/welcome.do")

public void welcomeHandler() {

}

对应的逻辑视图名为“welcome”

String此时逻辑视图名为返回的字符，如以下的方法：

@RequestMapping(method = RequestMethod.GET)

public String setupForm(@RequestParam("ownerId") int ownerId, ModelMap model) {

Owner owner = this.clinic.loadOwner(ownerId);

model.addAttribute(owner);

return "ownerForm";

}

对应的逻辑视图名为“ownerForm”

ModelMap和返回类型为void一样，逻辑视图名取决于对应请求的URL，

如下面的例子：

@RequestMapping("/vets.do")

public ModelMap vetsHandler() {

return new ModelMap(this.clinic.getVets());

}

对应的逻辑视图名为“vets”，返回的ModelMap将被作为请求对应的模型对象，

可以在JSP视图页面中访问到。

ModelAndView

返回方式

1使用无返回方法跳转,如果使用返回方法进行跳转的话,则会通过视图解析器进行以

prefix(前缀)+方法名+suffix(后缀)组成的页面文件名称.

2使用一个返回的字符串方法作为跳转,使用字符串跳转的话好处就是在return的时候可

以自己指定返回的名字,JSP组成是prefix(前缀)+返回的字符串+suffix(后缀)

3返回一个ModelAndView类型,使用setViewName方法则可以跳转到指定的页面.

路径匹配形式

1、单一Controller对应 单一的请求路径

2、单一Controller对应多个请求路径

3、单一Controller对应多个请求路径，且路径内可以含有参数的形式

Demo code and UseCase

@Controller

@RequestMapping("/login.do")

publicclass SinglePathWithController {}

@Controller

@SessionAttributes(types = {UserBean.class,String.class},value=http://www.mamicode.com/{"currentUser","message"})

publicclass AdapterMultiPathController {}

@Controller

@RequestMapping(value =http://www.mamicode.com/"/rest")

publicclass RestWithController {}

无返回

//无返回值无参数返回的是根据prefix前缀+@RequestMapping value +suffix

后缀组成

@RequestMapping("/springmvc/common")

publicvoidnovoid(HttpServletRequest request) {

request.setAttribute("message","novoid方法被调用");

}

返回字符串

1、作为视图路径方式

//根据路径直接匹配

@RequestMapping("/springmvc/multiReqPath1.do")

publicString multiReqPath1(HttpServletRequest request){

request.setAttribute("message","multiReqPath1方法被调用");

return"springmvc/common";

}

@RequestMapping("/springmvc/multiReqPath2.do")

publicString multiReqPath2(HttpServletRequest request){

request.setAttribute("message","multiReqPath2方法被调用");

return"/springmvc/common";

}

//根据参数匹配

@RequestMapping(params = "m=method1",method = RequestMethod.GET)

publicString method1(){

return"login/success";

}

//有参数参数名和请求url内的变量名一致

@RequestMapping(params = "m=method2")

publicString method2(Stringname,Stringpwd){

returnname;

}

//有参数参数名和请求url内的变量名不一致

@RequestMapping(params = "m=method3",method = RequestMethod.GET)

publicString method3(@RequestParam("loginName")Stringname,@RequestParam("loginPwd")Stringpwd,HttpServletRequest request){

request.setAttribute("message",(name + " " + pwd));

return"login/"+name;

}

2、作为Response内容方式

//无参数

@ResponseBody

@RequestMapping(params = "m=method4")

publicString method4(){

return"hello,guys";

}

//处理方法入参如何绑定URL 参数

@ResponseBody

@RequestMapping(params = "m=method5",method = RequestMethod.GET)

publicString method5(Stringname,Stringpwd,intdelay){

return"name:"+name+","+"pwd:"+pwd+","+"delay:"+delay;

}

@ResponseBody

@RequestMapping(params = "m=method6",method = RequestMethod.GET)

publicString method6(@RequestParam("userName")Stringname,DnTesttest){

return"DnTest:"+test.toString();

}

URL参数: userName参数将绑定到name上其他与DnTest类内属性名称一致的参数将绑定到test的对应的属性上，如果参数不全也不会报错

返回ModelAndView

@RequestMapping("/springmvc/modelAndView")

publicModelAndView modelAndView(){

ModelAndViewmav = newModelAndView();

mav.setViewName("/springmvc/common");

mav.addObject("message","modelAndView 方法被调用");

returnmav;

}

返回ModelMap

@RequestMapping("/springmvc/modelMap")

publicModelMap modelMap(ModelMapmodMap){

List<String> names = newArrayList<String>();

names.add("Rick");

names.add("Austin");

modMap.put("names", names);

modMap.put("message","hello guys");

modMap.put("comment","hello guys");

returnmodMap;

}

返回ModelMap

@RequestMapping("/springmvc/modelMap")

publicModelMap modelAndView(ModelMapmodMap){

List<String> names = newArrayList<String>();

names.add("Rick");

names.add("Austin");

modMap.put("hello","hello guys");

modMap.put("names", names);

returnmodMap;

}

@SessionAttribute & ModMap

//注解方式

@Controller

@SessionAttributes(types = {UserBean.class,String.class},value=http://www.mamicode.com/{"currentUser","message"})

publicclass AdapterMultiPathController {}

//方法体

@RequestMapping("/springmvc/modelMap2")

publicModelMap modelMapWithSession(ModelMapmodMap,HttpServletRequest request){

List<String> names = newArrayList<String>();

names.add("Rick");

names.add("Austin");

modMap.put("names",names);

modMap.put("message","hello guys");

modMap.put("comment","hello guys");

UserBeanuser = newUserBean();

user.setName("Rick");

user.setMobile("18938900256");

user.setTelephone(request.getParameter("userPhone"));

user.setNumber(request.getParameter("userNumber"));

modMap.put("currentUser", user);

returnmodMap;

}

//初次请求

spring mvc & reverse ajax

@ResponseBody

@RequestMapping(params = "m=method7",method = RequestMethod.GET)

publicString method7(Stringname,Stringpwd,intdelay,HttpServletRequest req){

req.startAsync();

DatestartTime = newDate();

try{

Thread.currentThread().sleep(delay);

}catch(InterruptedExceptione) {

e.printStackTrace();

}

DateentTime = newDate();

return"name:"+name+","+"pwd:"+pwd+","+"delay:"+delay+",startTime:"+

DateUtils.formatDate(startTime,"yyyy-MM-dd HH:mm:ss:SSS")+",endTime:"+

DateUtils.formatDate(entTime,"yyyy-MM-dd HH:mm:ss:SSS");

}

RestFull

@Controller

@RequestMapping(value =http://www.mamicode.com/"/rest")

publicclass RestWithController {}

@ResponseBody

@RequestMapping(value =http://www.mamicode.com/ "/{msg}", method = RequestMethod.GET)

publicString restString(@PathVariableString msg) {

returnmsg;

}

@ResponseBody

@RequestMapping(value =http://www.mamicode.com/ "/{path}/{value}", method = RequestMethod.GET)

publicString restXml(@PathVariableString path,@PathVariableString value) {

return"path:"+path+",value:"+value;

}

@ResponseBody

@RequestMapping(value =http://www.mamicode.com/ "/xml/{filename}", method = RequestMethod.GET)

publicString restFile(@PathVariableString filename) {

if(filename!=null) {

ProjectInitsinit = ProjectInits.getInstance();

Stringdir = init.get("resource.dir","C:/Projects/VoyagerWeb/resources");

FileUtilityfUtil = newFileUtility();

Stringcontent = fUtil.readFile(dir+"/"+filename+".xml");

returncontent;

}

else

return"Invalid xml file name ["+filename+"]";

}

验证 是否支持Overload

方式一

//验证是否支持Overload

@ResponseBody

@RequestMapping(value =http://www.mamicode.com/ "/validate/overload1", method = RequestMethod.GET)

publicString overloadMethod(Stringname){

returnname;

}

@ResponseBody

@RequestMapping(value =http://www.mamicode.com/ "/validate/overload2", method = RequestMethod.GET)

publicString overloadMethod(Stringname,DnTesttest){

return"DnTest:"+test.toString();

}

方式二

/验证是否支持Overload

@ResponseBody

@RequestMapping(params = "m=method11")

publicString method11(Stringname){

returnname;

}

@ResponseBody

@RequestMapping(params = "m=method11")

publicString method11(intage,DnTesttest){

return"DnTest:"+test.toString();

}