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BAEL-1567 use optional (#3849) 

* BAEL-1412 add java 8 spring data features

* BAEL-21 new HTTP API overview

* BAEL-21 fix executor

* BAEL-1432 add custom gradle task

* BAEL-1567 add samples of cookie and session in serlvet

* BAEL-1567 use stream api

* BAEL-1567 fix optional
This commit is contained in:
abialas 2018-03-18 21:02:16 +01:00 committed by maibin
parent e6024bfdd0
commit b2eaf0af58
3 changed files with 17 additions and 14 deletions
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8
javax-servlets/src/main/java/com/baeldung/servlets/CookieReader.java
View File

@ -3,6 +3,7 @@ package com.baeldung.servlets;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;
import java.util.Optional;
/**
* Created by adam.
@ -26,14 +27,13 @@ public class CookieReader {
* Reads cookie by key from request.
*
* @param key the key of a cookie
* @return returns cookie value (or null if cookie with given key does not exist)
* @return returns cookie value
*/
public String readCookie(String key) {
public Optional<String> readCookie(String key) {
return Arrays.stream(request.getCookies())
.filter(c -> key.equals(c.getName()))
.map(Cookie::getValue)
.findFirst()
.orElse(null);
.findFirst();
}
}

9
javax-servlets/src/main/java/com/baeldung/servlets/LoginServlet.java
View File

@ -5,6 +5,7 @@ import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
import java.util.Optional;
/**
* Created by adam.
@ -15,12 +16,12 @@ public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
CookieReader cookieReader = new CookieReader(request);
String uiColor = cookieReader.readCookie("uiColor");
String userName = cookieReader.readCookie("userName");
Optional<String> uiColor = cookieReader.readCookie("uiColor");
Optional<String> userName = cookieReader.readCookie("userName");
request.setAttribute("uiColor", uiColor != null ? uiColor : "blue");
request.setAttribute("uiColor", uiColor.isPresent() ? uiColor.get() : "blue");
if (userName == null || userName.isEmpty()) {
if (!userName.isPresent()) {
RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/login.jsp");
dispatcher.forward(request, response);
} else {

14
javax-servlets/src/main/java/com/baeldung/servlets/WelcomeServlet.java
View File

@ -8,6 +8,7 @@ import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Optional;
/**
* Created by adam.
@ -18,15 +19,16 @@ public class WelcomeServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
CookieReader cookieReader = new CookieReader(request);
String uiColor = cookieReader.readCookie("uiColor");
String userName = cookieReader.readCookie("userName");
Optional<String> uiColor = cookieReader.readCookie("uiColor");
Optional<String> userName = cookieReader.readCookie("userName");
if (userName == null || userName.isEmpty()) {
if (!userName.isPresent()) {
response.sendRedirect("/login");
} else {
request.setAttribute("uiColor", uiColor != null ? uiColor : "blue");
request.setAttribute("userName", userName);
request.setAttribute("sessionAttribute", request.getSession().getAttribute("sampleKey"));
request.setAttribute("uiColor", uiColor.isPresent() ? uiColor.get() : "blue");
request.setAttribute("userName", userName.get());
request.setAttribute("sessionAttribute", request.getSession()
.getAttribute("sampleKey"));
RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/welcome.jsp");
dispatcher.forward(request, response);