[RUBY] Comparison of WEB application development with Rails and Java Servlet + JSP

Comparison of WEB application development with Rails and Java Servlet + JSP

How to specify the routing

Rails Specified in routes.rb

routes.rb

Rails.application.routes.draw do
 get '/sample' => 'Controller name#Action name' 
 post '/sample' => 'Controller name#Action name' 
end 

Java Servlet + JSP Specified in XXXServlet.java annotation

XXXSerblet.java

package src;

import java.io.IOException;

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


@WebServlet("/sample")
public class XXXServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;


	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		RequestDispatcher dispatcher = request.getRequestDispatcher("Transition destination file");
		dispatcher.forward(request, response);
	}


	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");

		RequestDispatcher dispatcher = request.getRequestDispatcher("Transition destination file");
		dispatcher.forward(request, response);

	}

}

WEB application development with Java Servlet + JSP

Example: Login / log-off function

--You can access the ** INDEX page ** by typing http: // localhost: 8080 / SampleApp in your browser -Click the to INDEX PAGE link on the ** INDEX page ** to jump to the ** LOGIN page ** -Enter any name in the name field of ** LOGIN page ** and 1234 in the password field, and click the submit button to jump to the ** MAIN page **. --Even if you enter characters other than 1234 in the password field and click the submit button, you will not be taken to the ** MAIN page **. -Click the to LOG OUT link on the ** MAIN page ** to log out and return to the ** LOG IN page **

INDEX page

LOGIN page

MAIN page

Development environment

Code example

Model to hold user information

User.java

package model;
import java.io.Serializable;

public class User implements Serializable {
	private String name;
	private String password;

	public User() {};

	public User(String name,String password){
		this.name = name;
		this.password = password;
	}

	public String getName() {
		return name;
	}

	public String getPassword() {
		return password;
	}
}

Class that processes login information

LoginLogic.java

package model;

public class LoginLogic {
	public boolean execute(User user) {
		if(user.getPassword().equals("1234")){
			return true;
		}
		return false;
	}
}

Controller to handle login

Login.java

package src;

import java.io.IOException;

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

import model.LoginLogic;
import model.User;



@WebServlet("/Login")
public class Login extends HttpServlet {
	private static final long serialVersionUID = 1L;


	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/login.jsp");
		dispatcher.forward(request, response);
	}


	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");

		String userName = request.getParameter("name");
		String password = request.getParameter("password");
		User user = new User(userName,password);
		LoginLogic loginLogic = new LoginLogic();

		boolean isLogin = loginLogic.execute(user);

		if(isLogin==true) {
			HttpSession session = request.getSession();
			session.setAttribute("loginUser",user);
			response.sendRedirect("/SampleApp/Main");
		} else {
			response.sendRedirect("/SampleApp/Login");
		}
	}
}

Controller to handle logout

Logout.java

package src;

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;
import javax.servlet.http.HttpSession;

@WebServlet("/Logout")
public class Logout extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		HttpSession session = request.getSession();
		session.invalidate();
		response.sendRedirect("/SampleApp/Login");
	}
}

View to display ** INDEX page **

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>INDEX PAGE ｜ SAMPLE APP</title>
</head>
<body>
<h1>SAMPLE APP</h1>
<h2>INDEX PAGE</h2>
<a href="/SampleApp/Login">to LOGIN PAGE</a>
</body>
</html>

View to display ** LOGIN page **

login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>LOGIN FORM | SAMPLE APP</title>
</head>
<body>
<h1>SAMPLE APP</h1>
<h2>LOGIN FORM</h2>
<form action="/SampleApp/Login" method="post">
<p>Name:</p>
<input type="text" name="name">
<p>PassWord:</p>
<input type="password" name="password"><br>
<input type="submit" value="submit"><br>
<br>
</form>
<br>
<a href="/SampleApp/">to INDEX PAGE</a>
</body>
</html>

View to display ** MAIN page **

main.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="model.User" %>
<%
User loginUser = (User)session.getAttribute("loginUser");
%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title><%= loginUser.getName() %> | SAMPLE APP</title>
</head>
<body>
<h1>SAMPLE APP</h1>
<p>Hello,<%= loginUser.getName() %>!</p>
<h2>Articles posted by <%= loginUser.getName() %></h2>
<a href="/SampleApp/Logout">to LOG OUT</a>
</body>
</html>

Reference material

-[Introduction to Servlet & JSP (Refreshing Series)](https://www.amazon.co.jp/%E3%82%B9%E3%83%83%E3%82%AD%E3%83%AA% E3% 82% 8F% E3% 81% 8B% E3% 82% 8B-% E3% 82% B5% E3% 83% BC% E3% 83% 96% E3% 83% AC% E3% 83% 83% E3 % 83% 88-JSP% E5% 85% A5% E9% 96% 80-% E3% 82% B9% E3% 83% 83% E3% 82% AD% E3% 83% AA% E3% 82% B7% E3% 83% AA% E3% 83% BC% E3% 82% BA-% E5% 9B% BD% E6% 9C% AC / dp / 4844335804)]

• GitHub - tanakadaichi1989