SpringMVC - 获取请求参数，作用域

一、获取请求参数

1.原生serveltAPI

@Controller
public class TestController{

    @RequestMapping("/test01") 
    public String test01(HttpServletRequest request) {
   
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        System.out.println("username : " + username + ", password : " + password);
        return "success";
    }
  
}

2.控制器参数列表

@Controller
public class TestController{

    // 当请求参数与参数列表名一致时，会自动给形参赋值。
    @RequestMapping("/test01") 
    public String test01(String username,String password) {
        System.out.println("username : " + username + ", password : " + password);
        return "success";
    }
  
}

3.@Requestparam

@Controller
public class TestController{

    // 当请求参数与形参列表名不一致时，使用@Requestparam注解
    @RequestMapping("/test01") 
    public String test01(@RequestParam("username") String user_name, @Requestparam("password") String pass_word) {
        System.out.println("username : " + user_name + ", password : " + pass_word);
        return "success";
    }
  
}

4.@RequestHeader  获取请求头

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public String test01(@RequestHader("Host") String location) {
            System.out.println("Host : " + locaiont);
        return "success";
    }
  
}

5.@CookieValue   获取cookie存储的值

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public String test01(@CookieValue("JSESSIONID") String JSESSIONID) {
            System.out.println("JSESSIONID : " + JSESSIONID);
        return "success";
    }
  
}

6.实体类

@Controller
public class TestController{
    
    // 当请求参数与java实体类的属性一致，会将请求参数自动生成实体类
    @RequestMapping("/test01") 
    public String test01(User user) {
            System.out.println(user);
        return "success";
    }
  
}

二、作用域

四大作用域 ：

1.page  (淘汰)

2.request

3.session

4.application

向request域中存放数据

1.使用原生servletAPI

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public String test01(HttpServeltRequest request) {
        request.setAttribute("msg","servlet");
        return "success";
    }
  
}

2.使用ModelAndView

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public ModelAndView test01() {
        ModelAndView mv = new ModelAndView();
        mv.addObject("msg","ModelAndView");
        mv.setViewName("success");
        return mv;
    }
  
}

3.使用Model

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public String test01(Model model) {
             model.addAttribute("msg","model");
        return "success";
    }
  
}

4.使用ModelMap

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public String test01(ModelMap map) {
            map.addAttribute("msg","ModelMap");
        return "success";
    }
  
}

5.使用Map

@Controller
public class TestController{
    
    @RequestMapping("/test01") 
    public String test01(Map<String,String> map) {
            map.put("msg","map");
        return "success";
    }
  
}

     向session作用域存放数据

1.原生servlet

@Controller
public class TestController{
    
    @RequestMapping("/test03")
    public String test03(HttpServletRequest request) {
        HttpSession session = request.getSession();
        session.setAttribute("msg","session");
        return "success";
    }
  
}

      向application作用域存放数据

1.原生servlet

@Controller
public class TestController{
    
     @RequestMapping("/test03")
    public String test04(HttpServletRequest request) {
        HttpSession session = request.getSession();
        ServletContext application = session.getServletContext();
        application.setAttribute("msg","application");
        return "success";
    }
  
}