Servlet 기초 - 실습, '==' / .equals 차이

줘니(•̀ᴗ•́)و 2023. 1. 26. 19:15

728x90

1. HTML 파일 코드

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	<form action="Operation">
    
	<input type="text" name="num1">
	<select name="oper">
	<option>+</option>
	<option>-</option>
	<option>*</option>
	<option>/</option>
	</select>
	<input type="text" name="num2">
	<input type="submit" value="계산">
	
	</form>

</body>
</html>

2. Servlet 파일 코드

package Servlet0126;

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("/Operation")
public class Ex05Operation extends HttpServlet {
	private static final long serialVersionUID = 1L;


	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		// 1. 데이터 가져와 형변환하기
		int num1 = Integer.parseInt(request.getParameter("num1"));
		int num2 = Integer.parseInt(request.getParameter("num2"));
		String oper = request.getParameter("oper");

		// 2. if문 사용해 출력하기
		response.setContentType("text/html; charset=UTF-8");
		
		PrintWriter out = response.getWriter();

		if(oper.equals("+")) {
			out.print(num1+"+"+num2+"="+(num1+num2));
		}else if(oper.equals("-")) {
			out.print(num1+"-"+num2+"="+(num1-num2));
		}else if(oper.equals("*")) {
			out.print(num1+"*"+num2+"="+(num1*num2));
		}else if(oper.equals("/")) {
			out.print(num1+"/"+num2+"="+(num1/num2));
		}
	
	}

}