springboot请求参数的方法分享

转自:

http://www.java265.com/JavaFramework/SpringBoot/202206/3779.html

URL请求参数：
     是web客户端同服务器交流数据的一种方式
	 那么SpringBoot中如何从url中获取指定的参数值呢？
	 下文将一一道来,如下所示:

方式1:直接将参数写在Controller的形参中

    @RequestMapping("/addUser1")
    public String addUser1(String username,String password) {
        System.out.println("用户名:"+username);
        System.out.println("密码:"+password);
        return "index";
    }

http://localhost:8080/addUser1?username=chengcheng&password=87654321

方式2：使用HttpServletRequest的方式接收

    @RequestMapping("/addUser2")
    public String addUser2(HttpServletRequest request) {
        String username=request.getParameter("username");
        String password=request.getParameter("password");
        System.out.println("用户名:"+username);
        System.out.println("密码:"+password);
        return "index";
    }

方式3：使用bean对象接收参数

package demo.model;

public class UserModel {
    
    private String username;
    private String password;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    
}

    @RequestMapping("/addUser3")
    public String addUser3(UserModel user) {
        System.out.println("用户名:"+user.getUsername());
        System.out.println("密码:"+user.getPassword());
        return "index";
    }

方式4:使用@PathVariable获取路径中的参数

@RequestMapping(value="/addUser4/{username}/{password}",method=RequestMethod.GET)
public String addUser4(@PathVariable String username,@PathVariable String password) {
        System.out.println("用户名:"+username);
        System.out.println("密码:"+password);
        return "index";
    }
http://localhost:8080/addUser4/usernametest/pwd88888

方式5:使用@ModelAttribute注解获取POST请求的FORM表单数据

Jsp表单: 

 
     用户名: 

     密  码: 

      
      
 

    @RequestMapping(value="/addUser5",method=RequestMethod.POST)
    public String addUser5(@ModelAttribute("user") UserModel user) {
        System.out.println("username is:"+user.getUsername());
        System.out.println("password is:"+user.getPassword());
        return "demo/index";
    }

方式6:使用注解@RequestParam绑定请求参数到方法入参

当请求参数username不存在时会有异常发生
 可以通过设置属性required=false解决
  例
   @RequestParam(value="username", required=false)
  @RequestMapping(value="/addUser6",method=RequestMethod.GET)
    public String addUser6(@RequestParam("username") String username,@RequestParam("password") String password) {
        System.out.println("用户名:"+username);
        System.out.println("密码:"+password);
        return "demo/index";
    }