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[study]이론정리/Spring Boot

Spring MVC - 요청파라미터얻기1 (단일값)

by yoon9i 2024. 7. 2.

4> 요청 파라미터 얻기1- 단일값( name 하나에 value 하나 )
- 이전 서블릿/jsp 의 request.getParameter("name") 역할 및 POST 요청시 한글처리 명시적으로 구현.
- POST 요청시에도 한글처리가 지원됨.

방법1:
      @PostMapping("/login")
      public String add(HttpServletRequest request) {
        String userid = request.getParameter("userid");
        String passwd = request.getParameter("passwd");
        logger.info("logger: userid = {}, passwd = {}", userid, passwd);
        
        return "redirect:xxx"; 
      }

      ==> 서블릿/jsp 에서는 "userid" 가 없으면 null 값을 반환.

방법2:
     @PostMapping("/login")
      public String Login1(@RequestParam("userid") String userid, @RequestParam("passwd") String passwd) {
        
        logger.info("logger: userid = {}, passwd = {}", userid, passwd);
        
        return "redirect:xxx"; 
      }

      * @RequestParam 는 필수사항으로 반드시 name 값에 해당되는 파라미터가 제공되어야 한다.
        따라서 name 값에 해당되는 값이 없으면 null 이 아닌 400(bad request) 에러가 발생한다.
        필수사항을 옵션으로 변경가능하다. (에러가 아닌 null 값이 저장됨.)
        추가로 null 값 대신에 기본값 설정도 가능하다.

방법3:
      @PostMapping("/login")
      public String Login(@RequestParam(name = "userid2", 
                        required = false, 
                        defaultValue = "aaa") String userid, 
          @RequestParam("passwd") String passwd) {
        // @RequestParam(name = "userid2", required = false) String userid 
        // >>> logger: userid = null, passwd = bbb
        
        // @RequestParam(name = "userid2", required = false, defaultValue = "aaa") String userid
        // >>> logger: userid = aaa, passwd = bbb
        
        
        logger.info("logger: userid = {}, passwd = {}", userid, passwd);
        
        return "redirect:xxx"; 
      }

방법4:
name 값과 저장할 파라미터 변수가 동일하면 name 값 생략가능.

     @PostMapping("/login")
      public String Login(@RequestParam String userid,  // name 값과 변수값이 일치하면 name 값 생략가능
                @RequestParam("passwd") String pw) {
        
        logger.info("logger: userid = {}, passwd = {}", userid, pw);
        
        return "redirect:xxx"; 
      }

방법5:
DTO 에 직접 저장(단, name 값과 DTO 의 변수명이 동일한 경우)

     @PostMapping("/login")
      public String Login(LoginDTO dto) {
        
        logger.info("logger: userid = {}, passwd = {}", dto.getUserid(), dto.getPasswd());
        
        return "redirect:xxx"; 
      }

방법6:
Map 계열로 저장.

     @PostMapping("/login")
      public String Login(@RequestParam Map<String, String> map) {
        
        logger.info("logger: Map = {}", map); // logger: Map = {userid=홍길동, passwd=1234}
        
        return "redirect:xxx"; 
      }

 

package com.exam;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;


@SpringBootApplication
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
}
package com.exam.controller;

import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

import com.exam.dto.LoginDTO;

@Controller
public class MainController {
	
	Logger logger = LoggerFactory.getLogger(getClass());
	
	// 화면 요청
	@GetMapping("/login")
	public String list() {
		return "loginForm"; 
	}
	
	
	////////////////////////////////////////////////////////////
	// id 와 pw 얻어오는 작업
	
	// 방법1
	// 로직 요청
	// userid=aaa, passwd=1234 가정
	@PostMapping("/login1")
	public String Login1(HttpServletRequest request) {
		String userid = request.getParameter("userid");
		String passwd = request.getParameter("passwd");
		logger.info("logger: userid = {}, passwd = {}", userid, passwd);
		
		return "redirect:xxx"; 
	}
	
	// 방법2
	@PostMapping("/login2")
	public String Login2(@RequestParam("userid") String userid, @RequestParam("passwd") String passwd) {
		// @RequestParam("userid2") String userid >>> 400(bad request) 에러 발생
		
		logger.info("logger: userid = {}, passwd = {}", userid, passwd);
		
		return "redirect:xxx"; 
	}
	
	// 방법3
	@PostMapping("/login3")
	public String Login3(@RequestParam(name = "userid2", 
									  required = false, 
									  defaultValue = "aaa") String userid, 
			@RequestParam("passwd") String passwd) {
		// @RequestParam(name = "userid2", required = false) String userid 
		// >>> logger: userid = null, passwd = bbb
		
		// @RequestParam(name = "userid2", required = false, defaultValue = "aaa") String userid
		// >>> logger: userid = aaa, passwd = bbb
		
		
		logger.info("logger: userid = {}, passwd = {}", userid, passwd);
		
		return "redirect:xxx"; 
	}
	
	// 방법4
	@PostMapping("/login4")
	public String Login4(@RequestParam String userid,  // name 값과 변수값이 일치하면 name 값 생략가능
						@RequestParam("passwd") String pw) {
		
		logger.info("logger: userid = {}, passwd = {}", userid, pw);
		
		return "redirect:xxx"; 
	}
	
	// 방법5
	@PostMapping("/login5")
	public String Login5(LoginDTO dto) {
		
		logger.info("logger: userid = {}, passwd = {}", dto.getUserid(), dto.getPasswd());
		
		return "redirect:xxx"; 
	}
	
	// 방법6
	@PostMapping("/login")
	public String Login(@RequestParam Map<String, String> map) {
		
		logger.info("logger: Map = {}", map); // logger: Map = {userid=홍길동, passwd=1234}
		
		return "redirect:xxx"; 
	}
	
	////////////////////////////////////////////////////////////
	
	// PRG 패턴적용
	@GetMapping("/xxx")
	public String hello() {
		return "hello"; 
	}

}
package com.exam.dto;

public class LoginDTO {
	
	String userid;
	String passwd;
	
	// 생성자
	public LoginDTO() {
		super();
		// TODO Auto-generated constructor stub
	}
	
	public LoginDTO(String userid, String passwd) {
		super();
		this.userid = userid;
		this.passwd = passwd;
	}
	
	// getter & setter
	
	public String getUserid() {
		return userid;
	}
	
	public void setUserid(String userid) {
		this.userid = userid;
	}
	
	public String getPasswd() {
		return passwd;
	}
	
	public void setPasswd(String passwd) {
		this.passwd = passwd;
	}
	
	// toString
	@Override
	public String toString() {
		return "LoginDTO [userid=" + userid + ", passwd=" + passwd + "]";
	}
}
<%@ page 
         contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"        
%>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<p>안녕하세요</p>
<p>Hello</p>
</body>
</html>
<%@ page 
         contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"        
%>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
	<title>Insert title here</title>
</head>
<body>
	<h2>로그인화면</h2>
	<form action="login"  method="post">
	아이디:<input type="text" name="userid"><br>
	비번:<input type="text" name="passwd"><br>
	<input type="submit" value="로그인">
</form>
</body>
</html>
# application.properties
logging.level.org.springframework=info

# tomcat port 번호 변경
server.port=8090

# context 명 변경
server.servlet.context-path=/app

# jsp의 경로와 확장자 지정
spring.mvc.view.prefix=/WEB-INF/views/
spring.mvc.view.suffix=.jsp


spring.mvc.pathmatch.matching-strategy=ant-path-matcher
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
	http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.7.18</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.exam</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>demo</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>11</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-devtools</artifactId>
		</dependency>
	<dependency>
		<groupId>org.apache.tomcat.embed</groupId>
		<artifactId>tomcat-embed-jasper</artifactId>
		<scope>provided</scope>
	</dependency> 
	<dependency>
		<groupId>javax.servlet</groupId>
		<artifactId>jstl</artifactId>
	</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

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