Servlet / JSP #08 Submit과 배열 입력

underlier12·2020년 1월 24일

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SERVLET&JSP

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08. Submit과 배열 입력

여러개의 Submit

이번에는 덧셈 연산 뿐 아니라 뺄셈 연산도 가능하도록 Submit 버튼을 두개로 연동해본다.

소스 작성

calc.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Calculation</title>
</head>
<body>
	<div>
		<form action="calc" method="post">
			<div>
				<label>x : </label><input name="x" type="text">
			</div>
			<div>
				<label>y : </label><input name="y" type="text">
			</div>
			<div>
				<input type="submit" name="operator" value="덧셈"/>
				<input type="submit" name="operator" value="뺄셈"/>
				
			</div>
		</form>
	</div>
</body>
</html>

버튼 이름이 같더라도 선택되는 것에 따라 전달되는 value가 다름

Calc.java

package com.newlecture.web;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/calc")
public class Calc extends HttpServlet{
	@Override
	protected void service(HttpServletRequest request
			, HttpServletResponse response) 
					throws ServletException, IOException {
		
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html; charset=UTF-8");
		
		PrintWriter out = response.getWriter();
		
		String x_ = request.getParameter("x");
		String y_ = request.getParameter("y");
		String op = request.getParameter("operator");
		
		int x = 0;
		int y = 0;
		
		if(x_ != null && x_ != "") {
			x = Integer.parseInt(x_);
		}
		
		if(y_ != null && y_ != "") {
			y = Integer.parseInt(y_);
		}
		if(op.equals("덧셈")) {
			out.println("덧셈 결과 = " + (x + y));					
		} else {
			out.println("뺄셈 결과 = " + (x - y));
		}
		
	}
}

배열 입력

입력 사항 추가

변수의 이름을 같게 설정하면 배열로 값이 전달 됨

add2.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Registration</title>
</head>
<body>
	<div>
		<form action="add2" method="post">
			<div>
				<input name="num" type="text">
				<input name="num" type="text">
				<input name="num" type="text">
				<input name="num" type="text">
			</div>
			<div>
				<input type="submit" value="계산"/>
			</div>
		</form>
	</div>
</body>
</html>

Add2.java

package com.newlecture.web;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/add2")
public class Add2 extends HttpServlet{
	@Override
	protected void service(HttpServletRequest request
			, HttpServletResponse response) 
					throws ServletException, IOException {
		
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html; charset=UTF-8");
		
		PrintWriter out = response.getWriter();
		
		String[] num_ = request.getParameterValues("num");
		
		int result = 0;
		
		for(int i = 0; i < num_.length; i++) {
			int num = Integer.parseInt(num_[i]);
			result += num;
		}
		
		out.println("덧셈 결과 = " + result);		
		
	}
}