JSP/이론
form으로 데이터 빈공백으로 보내면 null체크여부
SEOKIHOUSE
2023. 7. 3. 14:14
1)텍스트박스는 null체크가 안되고 파라미터 이름이 다르면 null체크가 된다
2)라디오버튼은 null체크가 된다
3)체크박스
4)textarea는 not null뜬다
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="testServlet" method="POST">
<input type="text" name="name"><br>
여자<input type="radio" name="gender" value="woman"><br>
남자<input type="radio" name="gender" value="man"><br>
<input type="checkbox" name="hobby" value="독서">독서
<input type="checkbox" name="hobby" value="운동">운동
<input type="checkbox" name="hobby" value="코딩">코딩<br>
<textarea rows="5" cols="5" name="textarea"></textarea>
<input type="submit" value="전송">
</form>
</body>
</html>package servlets;
import java.io.IOException;
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("/testServlet")
public class TestServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String username = request.getParameter("name");
if(username != null) {
System.out.println("not null");
}else {
System.out.println("null");
}
System.out.println("-----------------------");
if(username.equals("")) {
System.out.println("빈문자열");
}else {
System.out.println("not null");
}
System.out.println("------------");
username = request.getParameter("name1");
if(username != null) {
System.out.println("not null");
}else {
System.out.println("null");
}
System.out.println("radio------------");
String gender = request.getParameter("gender");
if(gender != null) {
System.out.println("not null");
}else {
System.out.println("null");
}
System.out.println("----checkbox-----");
String[] checkBox = request.getParameterValues("hobby");
if(checkBox != null) {
System.out.println("not null");
}else {
System.out.println("null");
}
System.out.println("---textarea");
String textarea = request.getParameter("textarea");
if(textarea != null) {
System.out.println("not null");
}else {
System.out.println("null");
}
if(textarea.equals("")) {
System.out.println("not null");
}else {
System.out.println("null");
}
}
}