Published 2022. 9. 17. 15:07

Spring MVC - @RequestParam

한글 필터

web.xml

	<!-- 한글 변환 필터 시작 -->
	<filter>
		<filter-name>encodingFilter</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>UTF-8</param-value>
		</init-param>
		<init-param>
			<param-name>forceEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	
	<filter-mapping>
		<filter-name>encodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	<!-- 한글 변환 필터 끝 -->

HomeController.java

package com.fastcampus.app;

import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;


import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class HomeController {

	@RequestMapping(value="/", method = RequestMethod.GET)
	public String main(Locale locale, Model model) {
		
		Date date = new Date();
		DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, locale);
		
		String formattedDate = dateFormat.format(date);
		
		model.addAttribute("serverTime", formattedDate);
		return "home";
	}
}

home.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page session="false" %>
<html>
<head>
	<title>Home</title>
</head>
<body>
<h1>
	Hello world!  
</h1>

<P>  The time on the server is ${serverTime}. </P>
</body>
</html>

RequestParamTest.java

package com.fastcampus.app;

import java.util.Date;

import javax.servlet.http.HttpServletRequest;

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

@Controller
public class RequestParamTest {
	@RequestMapping("/requestParam")
	public String main(HttpServletRequest request) {
		String year = request.getParameter("year");
//		http://localhost/ch2/requestParam         ---->> year=null
//		http://localhost/ch2/requestParam?year=   ---->> year=""
//		http://localhost/ch2/requestParam?year    ---->> year=""
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}

	@RequestMapping("/requestParam2")
//	public String main2(@RequestParam(name="year", required=false) String year) {   // 아래와 동일 
	public String main2(String year) {   
//		http://localhost/ch2/requestParam2         ---->> year=null
//		http://localhost/ch2/requestParam2?year    ---->> year=""
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}

	@RequestMapping("/requestParam3")
//		public String main3(@RequestParam(name="year", required=true) String year) {   // 아래와 동일 
		public String main3(@RequestParam String year) {   
//		http://localhost/ch2/requestParam3         ---->> year=null   400 Bad Request. required=true라서 
//		http://localhost/ch2/requestParam3?year    ---->> year=""
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";	
	}

	@RequestMapping("/requestParam4")
	public String main4(@RequestParam(required=false) String year) {   
//		http://localhost/ch2/requestParam4         ---->> year=null 
//		http://localhost/ch2/requestParam4?year    ---->> year=""   
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}

	@RequestMapping("/requestParam5")
	public String main5(@RequestParam(required=false, defaultValue="1") String year) {   
//		http://localhost/ch2/requestParam5         ---->> year=1   
//		http://localhost/ch2/requestParam5?year    ---->> year=1   
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}
	
// =======================================================================
	
	@RequestMapping("/requestParam6") 
	public String main6(int year) {   
//		http://localhost/ch2/requestParam6        ---->> 500 java.lang.IllegalStateException: Optional int parameter 'year' is present but cannot be translated into a null value due to being declared as a primitive type. Consider declaring it as object wrapper for the corresponding primitive type.
//		http://localhost/ch2/requestParam6?year   ---->> 400 Bad Request, nested exception is java.lang.NumberFormatException: For input string: "" 
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}
	
	@RequestMapping("/requestParam7") 
	public String main7(@RequestParam int year) {   
//		http://localhost/ch2/requestParam7        ---->> 400 Bad Request, Required int parameter 'year' is not present
//		http://localhost/ch2/requestParam7?year   ---->> 400 Bad Request, nested exception is java.lang.NumberFormatException: For input string: "" 
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}

	@RequestMapping("/requestParam8") 
	public String main8(@RequestParam(required=false) int year) {   
	//	http://localhost/ch2/requestParam8        ---->> 500 java.lang.IllegalStateException: Optional int parameter 'year' is present but cannot be translated into a null value due to being declared as a primitive type. Consider declaring it as object wrapper for the corresponding primitive type.
	//	http://localhost/ch2/requestParam8?year   ---->> 400 Bad Request, nested exception is java.lang.NumberFormatException: For input string: "" 
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}
	
	@RequestMapping("/requestParam9") 
	public String main9(@RequestParam(required=true) int year) {   
	//	http://localhost/ch2/requestParam9        ---->> 400 Bad Request, Required int parameter 'year' is not present
	//	http://localhost/ch2/requestParam9?year   ---->> 400 Bad Request, nested exception is java.lang.NumberFormatException: For input string: "" 
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}
	
	@RequestMapping("/requestParam10")   
	public String main10(@RequestParam(required=true, defaultValue="1") int year) {   
	//	http://localhost/ch2/requestParam10        ---->> year=1   
	//	http://localhost/ch2/requestParam10?year   ---->> year=1   
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}

	@RequestMapping("/requestParam11")   
	public String main11(@RequestParam(required=false, defaultValue="1") int year) {   
//		http://localhost/ch2/requestParam11        ---->> year=1   
//		http://localhost/ch2/requestParam11?year   ---->> year=1   
		System.out.printf("[%s]year=[%s]%n", new Date(), year);
		return "yoil";
	}
} // class

예외 처리

	@ExceptionHandler(Exception.class)
	public String cather(Exception e) {
		return "yoilError";
	}

log4j.xml 에서 로깅 레벨 trace 로

	<logger name="org.springframework.web">
		<level value="trace" />
	</logger>

MVC1

package com.fastcampus.app;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Calendar;

@Controller
public class YoilTellerMVC {
	
	@ExceptionHandler(Exception.class)
	public String catcher(Exception ex) {
		ex.printStackTrace();
		return "yoilError";
		
	}
	
    @RequestMapping("/getYoilMVC") // http://localhost/app/getYaoilMVC?year=2021&month=10&day=1
    public String main(int year, int month, int day, Model model) throws IOException {

    	if(!isValid(year, month, day)) {
    		return "yoilError";
    	}
    	
        // 2. 처리
        char yoil = getYoil(year, month, day);
        
        model.addAttribute("year", year);
        model.addAttribute("month", month);
        model.addAttribute("day", day);
        model.addAttribute("yoil", yoil);
        return "yoil";

        
    }

	    private boolean isValid(int year, int month, int day) {    
    	if(year==-1 || month==-1 || day==-1) 
    		return false;
    	
    	return (1<=month && month<=12) && (1<=day && day<=31); // 간단히 체크 
    }

	private char getYoil(int year, int month, int day) {
		Calendar cal = Calendar.getInstance();
        cal.set(year, month - 1, day);

        int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
        return " 일월화수목금토".charAt(dayOfWeek);
	}
}

MVC2

파라미터에 @ReqeustParam 사용

package com.fastcampus.app;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Calendar;

@Controller
public class YoilTellerMVC2 {
	
	@ExceptionHandler(Exception.class)
	public String catcher(Exception ex) {
		ex.printStackTrace();
		return "yoilError";
		
	}
	
    @RequestMapping("/getYoilMVC2") // http://localhost/app/getYoilMVC2?year=2021&month=10&day=1
    public String main(@RequestParam(required=true) int year,
    		@RequestParam(required=true) int month,
    		@RequestParam(required=true) int day, Model model) throws IOException {

    	if(!isValid(year, month, day)) {
    		return "yoilError";
    	}
    	
        // 2. 처리
        char yoil = getYoil(year, month, day);
        
        model.addAttribute("year", year);
        model.addAttribute("month", month);
        model.addAttribute("day", day);
        model.addAttribute("yoil", yoil);
        return "yoil";

        
    }

    private boolean isValid(int year, int month, int day) {    
    	if(year==-1 || month==-1 || day==-1) 
    		return false;
    	
    	return (1<=month && month<=12) && (1<=day && day<=31); // 간단히 체크 
    }

	private char getYoil(int year, int month, int day) {
		Calendar cal = Calendar.getInstance();
        cal.set(year, month - 1, day);

        int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
        return " 일월화수목금토".charAt(dayOfWeek);
	}
}

MVC4

year, month, day 매개변수를 하나로 합치자

package com.fastcampus.app;

import java.io.IOException;
import java.util.Calendar;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class YoilTellerMVC4 {
	
	@ExceptionHandler(Exception.class)
	public String catcher(Exception ex) {
		ex.printStackTrace();
		return "yoilError";
		
	}
	
    @RequestMapping("/getYoilMVC4") // http://localhost/app/getYoilMVC4?year=2021&month=10&day=1
    public String main(Mydate date, Model model) throws IOException {

    	if(!isValid(date)) {
    		return "yoilError";
    	}
    	
        // 2. 처리
        char yoil = getYoil(date);
        
        model.addAttribute("myDate", date);

        model.addAttribute("yoil", yoil);
        return "yoil";

        
    }

	private boolean isValid(Mydate date) {
	
		return isValid(date.getYear(), date.getMonth(), date.getDay());
	}

	private char getYoil(Mydate date) {
		// TODO Auto-generated method stub
		return getYoil(date.getYear(), date.getMonth(), date.getDay());
	}

    private boolean isValid(int year, int month, int day) {    
    	if(year==-1 || month==-1 || day==-1) 
    		return false;
    	
    	return (1<=month && month<=12) && (1<=day && day<=31); // 간단히 체크 
    }

	private char getYoil(int year, int month, int day) {
		Calendar cal = Calendar.getInstance();
        cal.set(year, month - 1, day);

        int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
        return " 일월화수목금토".charAt(dayOfWeek);
	}
}

yoil.jsp

<%@ page contentType="text/html;charset=utf-8" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page session="false" %>
<html>
<head>
	<title>Home</title>
</head>
<body>
<P>  ${myDate.year }년 ${myDate.month }월 ${myDate.day }일은 ${yoil }입니다. </P>
</body>
</html>

원리

package com.fastcampus.app;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.springframework.util.StringUtils;

public class SetterCall {
	public static void main(String[] args) throws Exception{
		Map<String, String> map = new HashMap<>();
		map.put("year", "2021");
		map.put("month", "10");
		map.put("day", "1");
		
		Class<?> type = Class.forName("com.fastcampus.ch2.MyDate");

		// MyDate인스턴스를 생성하고, map의 값으로 초기화한다. 
		Object obj = dataBind(map, type);
		System.out.println("obj="+obj); // obj=[year=2021, month=10, day=1]
	} // main

	private static Object dataBind(Map<String, String> map, Class<?> clazz) throws Exception {
		// 1. MyDate인스턴스 생성
//		Object obj = clazz.newInstance(); // deprecated method
		Object obj = clazz.getDeclaredConstructor().newInstance(new Object[0]);

		// 2. MyDate인스턴스의 setter를 호출해서, map의 값으로 MyDate를 초기화
		// 	 2-1. MyDate의 모든 iv를 돌면서 map에 있는지 찾는다.
		// 	 2-2. 찾으면, 찾은 값을 setter로 객체에 저장한다.
		Field[] ivArr = clazz.getDeclaredFields();
		
		for(int i=0;i<ivArr.length;i++) {
			String name = ivArr[i].getName();
			Class<?>  type = ivArr[i].getType();
			
			// map에 같은 이름의 key가 있으면 가져와서 setter호출 
			Object value = map.get(name); // 못찾으면 value의 값은 null
			Method method = null;
			
			try {   // map에 iv와 일치하는 키가 있을 때만, setter를 호출
				if(value==null) continue;
				
				method = clazz.getDeclaredMethod(getSetterName(name), type); // setter의 정보 얻기	
				System.out.println("method="+method);
				method.invoke(obj, convertTo(value, type)); // obj의 setter를 호출
			} catch(Exception e) {
				e.printStackTrace();
			}
		}
		
		System.out.println(Arrays.toString(ivArr));
		
		return obj;
	}

	private static Object convertTo(Object value, Class<?> type) {
		// value의 타입과 type의 타입이 같으면 그대로 반환
		if(value==null || type==null || type.isInstance(value))
			return value;
		
		// value의 타입과 type이 다르면, 변환해서 반환
		if(String.class.isInstance(value) && type==int.class) // String -> int
			return Integer.valueOf(""+value);

		return value;
	}

	// iv의 이름으로 setter의 이름을 만들어서 반환하는 메서드("day" -> "setDay")
	private static String getSetterName(String name) {
//		return "set"+name.substring(0,1).toUpperCase()+name.substring(1);
		return "set" + StringUtils.capitalize(name); // org.springframework.util.StringUtils
	}
}

/*
[실행결과]
method=public void com.fastcampus.ch2.MyDate.setYear(int)
method=public void com.fastcampus.ch2.MyDate.setMonth(int)
method=public void com.fastcampus.ch2.MyDate.setDay(int)
[private int com.fastcampus.ch2.MyDate.year, private int com.fastcampus.ch2.MyDate.month, private int com.fastcampus.ch2.MyDate.day]
obj=[year=2021, month=10, day=1]
 */

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Spring MVC - @RequestParam

한글 필터

MVC1

MVC2

MVC4

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