springmvc之获取参数的方法(必看)

  springDispatcherServlet
  org.springframework.web.servlet.DispatcherServlet
  
   contextConfigLocation
   classpath:springmvc.xml
  
  1
 

  
 
  springDispatcherServlet
  /
 
 
   
  
   CharacterEncodingFilter
  org.springframework.web.filter.CharacterEncodingFilter
  
  
   encoding
   utf-8
  
  
  
   forceEncoding
   true
  
  
  
   CharacterEncodingFilter
   /
  
   
  
   HiddenHttpMethodFilter
  org.springframework.web.filter.HiddenHttpMethodFilter
   
  
   HiddenHttpMethodFilter
   /*
  

 hello

 获取请求参数

 获取请求头

 

  图书id

  图书name

  图书author

  图书price

  图书sales

  图书stock

  

  
  作者name;

  作者address;

  
 
 

 
给页面携带数据
 output01

 
成功！
 ${msg}===${reMsg}
　

 
测试数据带在了哪个scope
 request:${requestScope.msg }
 
 session:${sessionScope.msg }
 
 application:${applicationScope.msg}

public class Author {
  private String name;
  private String address;　　　Book.java：　

public class Book {
 private int id;
 private String name;
 private double price;
 private int sales;
 private int stock;
 private Author person;
 private String imgPath = "static/img/default.jpg";
 private String author;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {
 
 @RequestMapping("/hello") //连接地址必须加上"/hello"
 public String hello(){
  return "success";
  
 }
}　　

@Controller
public class TestParamController {
 
 /**
  * 1、直接给方法的参数位置写上一个和请求带来的参数的名字相同的变量
  * 2、这个变量就封装的是带来的参数的值
  * user = request.getParameter("user")
  * 3、如果没有就是null
  * 
  * @RequestParam("user")：指定获取哪个参数的值
  * 1、默认发送请求必须带上这个参数；
  *   否则：HTTP Status 400 - Required String parameter 'user' is not present
  * 2、required=false可以设置不是必须的；没带null
  * 3、defaultValue="未命名"指定没带时的默认值；
  *   user = request.getParameter("user");
  */
 
 @RequestMapping("/handle01")
 public String handle01(
   @RequestParam(value = "user", required = false, defaultValue = "未命名") String user) {
  System.out.println("获取的User:" + user);
  return "success";
 }
 
 /**
  * 获取请求头；
  *   request.getHeader("User-Agent")
  * 注解做了下面这些事情
  * @RequestHeader("User-Agent")String userAgent;
  *   userAgent = request.getHeader("User-Agent");*/
 @RequestMapping("/handle02")
 public String handle02(
   @RequestHeader(value = "User-Agent", required = false, defaultValue = "没有的") String userAgent) {
  System.out.println("User-Agent:" + userAgent);
  return "success";
 }
 
 /**
  * 获取某个cookie的值;
  * JSESSIONID=B05C018F82AA1B0BD3845831FADFE49A
  * @CookieValue("JSESSIONID")String jid
  * 注解做了下面这些事情
  * Cookie[] cookies = request.getCookies();
  * for(Cookie c:cookies){
  *  if(c.getName().equals("JSESSIONID")){
  *   jid = c.getValue();
  *  }
  * }*/
 @RequestMapping("/handle03")
 public String handle03(
   @CookieValue(value = "JSESSIONID", required = false, defaultValue = "hhhhh") String jid) {
  System.out.println("jid：" + jid);
  return "success";
 }

 /*传入POJO；直接帮我们封装页面的值； 方便简单，少写很多代码，实现代码分离，解耦和
  * 1、book = new Book();
  * 2、把book对象中的每一个属性的值查出来,request.getParameter(属性)；
  * 3、把这个值设置进去
  * 注意：因为SpringMVC会进行类型转换，所以提交的数据一定要是合法的，否则400错误*/
 @RequestMapping("/saveBook")
 public String handle04(Book book) {
  System.out.println("book的值：" + book);
  return "success";
 }

 @RequestMapping("/handle05")
 // pringMVC还允许我们在请求参数上使用原生的ServletAPI HttpServletRequest HttpServletResponse
 // HttpSession
 public String handle05(HttpSession session, HttpServletRequest request,
   HttpServletResponse response) {
  session.setAttribute("msg", "哈哈哈");

  request.setAttribute("reqMsg", "嘿嘿嘿");

  return "success";
 }

}

@Controller //给页面携带数据
public class DataOutPutController {

 /**
  * 1、返回值改为ModelAndView（包含模型数据（Model）和要去的页面地址（View））；
  *   数据放在请求域中；
  * 2、在请求参数上传入Model、Map、ModelMap都行；给他们里面保存的数据会放在请求域中
  * Model、Map、ModelMap最终其实都是再有用BindingAwareModelMap；
  * 相当于给BindingAwareModelMap中保存数据就是给请求域中保存
  * Model   Map
  *  ||   ||
  *  ||   \/
  *  ||  ModelMap
  *  \/   \/
  *  ExtendedModelMap【隐含模型】 extends ModelMap implements Model
  *   \/
  *  BindingAwareModelMap
  * @return
  */
 @RequestMapping("/output04")
 public String output04(ModelMap model){
  //视图解析器会对视图名进行拼串
  model.addAttribute("msg","output04");
  System.out.println(model.getClass());
  return "testScope";
  
 }
 @RequestMapping("/output03")
 public String output03(Model model){
  model.addAttribute("msg", "output03");
  System.out.println(model.getClass());
  return "testScope";
 }
 @RequestMapping("/output02")
 public String output02(Mapmap){
  //视图解析器会对视图名进行拼串
  map.put("msg", "output02");
  System.out.println(map.getClass());
  return "testScope";
 }
 @RequestMapping("/output01")
 public ModelAndView output01(){
  //视图解析器会对视图名进行拼串
  ModelAndView modelAndView = new ModelAndView();
  modelAndView.setViewName("testScope");
  modelAndView.addObject("msg", "output01");
  return modelAndView;
  
 }
}