Spring MVC_⯐

package com.example.demo;

@Controller // 将UserController变成一个Handler
@RequestMapping("/user") // 指定控制器映射的URL
public class UserController {

  @RequestMapping(value = "/register") // 处理方法对应的URL，相对于类的URL
  public String register() {
    return "user/register"; // 返回逻辑视图名
  }
}

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>

@RequestMapping("/{userId}")
public ModelAndView showDetail(@PathVariable("userId") String userId){
    ModelAndView mav = new ModelAndView();
    mav.setViewName("user/showDetail");
    mav.addObject("user", userService.getUserById(userId));
    return mav;
}

@Controller
@RequestMapping("/owners/{ownerId}")
public class RelativePathUriTemplateController {

   @RequestMapping("/pets/{petId}")
   public void findPet(@PathVariable String ownerId, 
                                 @PathVariable String petId, Model model) {
     …
   }
}

@RequestMapping(value="/delete", params="userId") 
public String test1(@RequestParam("userId") String userId){
}

@RequestMapping(value="/show",headers="content-type=text/*")②
public String test2(@RequestParam("userId") String userId){}

@RequestMapping(value="/handle1")
public String handle1(@RequestParam("userName") String userName,
              @RequestParam("password") String password,
              @RequestParam("realName") String realName){
    ...
}

@RequestMapping(value="/handle2")
public String handle2(@CookieValue("JSESSIONID") String sessionId,
       @RequestHeader("Accept-Language") String accpetLanguage){
  ...
}

@RequestMapping(value = "/handle14")
public String handle14(User user) {
    //…
}

@RequestMapping(value = "/handle21")
public void handle21(HttpServletRequest request,HttpServletResponse response) {
  String userName = WebUtils.findParameterValue(request, "userName");
  response.addCookie(new Cookie("userName", userName));
}

public String handle23(HttpSession session) {
  session.setAttribute("sessionId", 1234);
  return "success";     
}

public String handle24(HttpServletRequest request,
                                    @RequestParam("userName")String userName) {
  //…
  return "success";
}

@RequestMapping(value = "/handle25")
public String handle25(WebRequest request) {
    String userName = request.getParameter("userName");
    return "success";
}

@RequestMapping(value = "/handle31")
public void handle31(OutputStream os) throws IOException{
       Resource res = new ClassPathResource("/image.jpg");//读取类路径下的图片文件
       FileCopyUtils.copy(res.getInputStream(), os);//将图片写到输出流中
}

@RequestMapping(value = "/handle32")
public void handle31(Locale locale) throws IOException{
  //...
}

@RequestMapping(value = "/handle41")
public String handle41(@RequestBody  String requestBody ) {
      System.out.println(requestBody);
      return "success";
}

@ResponseBody
@RequestMapping(value = "/handle42/{imageId}")
public byte[] handle42(@PathVariable("imageId") String imageId) throws IOException {
       System.out.println("load image of "+imageId);
       Resource res = new ClassPathResource("/image.jpg");
       byte[] fileData =FileCopyUtils.copyToByteArray(res.getInputStream());
       return fileData;
}

@RequestMapping(value = "/handle43")
public String handle43(HttpEntity<String> httpEntity){                             
     long contentLen = httpEntity.getHeaders().getContentLength();  
     System.out.println(httpEntity.getBody());
      return "success";
}

@RequestMapping(params = "method=login")   
public ResponseEntity<String> doFirst(){   
    HttpHeaders headers = new HttpHeaders();   
    MediaType mt=new MediaType("text","html",Charset.forName(“UTF-8"));   
    headers.setContentType(mt);   
    ResponseEntity<String> re=null;   
    String return = new String("test");   
    re=new ResponseEntity<String>(return,headers, HttpStatus.OK);   
    return re;   
}

public class User {
  @DateTimeFormat(pattern="yyyy-MM-dd")
  private Date birthday;
}

public class User {   
  @Pattern(regexp="w{4,30}")
  private String userName;

  @Length(min=2,max=100)
  private String realName;

  @Past 
  @DateTimeFormat(pattern="yyyy-MM-dd")
  private Date birthday;

  @DecimalMin(value="1000.00")
  @DecimalMax(value="100000.00") 
  @NumberFormat(pattern="#,###.##")
  private long salary;
}

@Controller
@RequestMapping("/user")
public class UserController {
  @RequestMapping(value = "/handle91")
  public String handle91(@Valid  User user,
    BindingResult bindingResult){       if(bindingResult.hasErrors()){
      return "/user/register3";
    }else{
          return "/user/showUser";
    }
  }
}

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"      uri="http://java.sun.com/jsp/jstl/core" %>   
<%@ taglib prefix="form"   uri="http://www.springframework.org/tags/form" %>
<html>
<head>
<title>注册用户</title>
  <style>.errorClass{color:red}</style>
</head>
<body> 
  <form:form modelAttribute="user"  action="user/handle91.html">
    <form:errors path="*"/>
    <table>
      <tr>
        <td>用户名：</td>
        <td>
          <form:errors path="userName" cssClass="errorClass"/>
          <form:input path="userName" />
        </td>
      </tr>
            …       
    </table>
  </form:form>
</body>
</html>

public class User {   
      @Pattern(regexp="w{4,30}")->假设发生错误
      private String userName;
}

@RequestMapping(method = RequestMethod.POST)
public ModelAndView createUser(User user) {
    userService.createUser(user);
    ModelAndView mav = new ModelAndView();
    mav.setViewName("user/createSuccess");
    mav.addObject("user", user);
    return mav;
}

//访问UserController中任何一个请求处理方法前，Spring MVC先执行该方法，并将返回值以user为键添加到模型中
@ModelAttribute("user")
public User getUser(){
    User user = new User();
    user.setUserId("1001"); 
    return user;
}

@RequestMapping(value = "/handle62")  
public String  handle62(@ModelAttribute("user") User user){
  //在此，模型数据会赋给User的入参，然后再根据HTTP请求消息进一步填充覆盖user对象
    user.setUserName("tom");
    return "/user/showUser";
}

@RequestMapping(value = "/handle63")
public String  handle63(ModelMap modelMap){
     modelMap.addAttribute("testAttr","value1");
     User user = (User)modelMap.get("user");
     user.setUserName("tom");       
     return "/user/showUser";
}

@Controller
@RequestMapping("/user")
@SessionAttributes(“user”)  //①将②处的模型属性自动保存到HttpSession中
public class UserController {

    @RequestMapping(value = "/handle71")
    public String  handle71(@ModelAttribute(“user”) User user){ //②
        user.setUserName("John");
        return "redirect:/user/handle72.html";
    }

    @RequestMapping(value = "/handle72")
    public String  handle72(ModelMap modelMap,SessionStatus sessionStatus){
        User user = (User)modelMap.get(“user”); //③读取模型中的数据
        if(user != null){
            user.setUserName("Jetty");
            sessionStatus.setComplete();  //④让Spring MVC清除本处理器对应的会话属性

        }
        return "/user/showUser";
    }       
}