From e577b2cb78dcc219d69e02ad1b11e20deeb76850 Mon Sep 17 00:00:00 2001
From: Manfred <77407079+manfred106@users.noreply.github.com>
Date: Sun, 9 Jul 2023 04:24:38 +0100
Subject: [PATCH] BAEL-6670: Reading a JSP variable from JavaScript (#14337)

---
 spring-boot-modules/spring-boot-jsp/pom.xml   | 11 +++++++
 .../jsp/controller/JSPVariableController.java | 31 +++++++++++++++++++
 .../main/webapp/WEB-INF/jsp/jsp-var/by-el.jsp | 18 +++++++++++
 .../webapp/WEB-INF/jsp/jsp-var/by-jsp.jsp     | 16 ++++++++++
 .../webapp/WEB-INF/jsp/jsp-var/by-jstl.jsp    | 19 ++++++++++++
 .../webapp/WEB-INF/jsp/jsp-var/to-dom.jsp     | 19 ++++++++++++
 6 files changed, 114 insertions(+)
 create mode 100644 spring-boot-modules/spring-boot-jsp/src/main/java/com/baeldung/boot/jsp/controller/JSPVariableController.java
 create mode 100644 spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-el.jsp
 create mode 100644 spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jsp.jsp
 create mode 100644 spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jstl.jsp
 create mode 100644 spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/to-dom.jsp

diff --git a/spring-boot-modules/spring-boot-jsp/pom.xml b/spring-boot-modules/spring-boot-jsp/pom.xml
index ab81d65cc6..9c6d0fcc0b 100644
--- a/spring-boot-modules/spring-boot-jsp/pom.xml
+++ b/spring-boot-modules/spring-boot-jsp/pom.xml
@@ -46,12 +46,22 @@
             <artifactId>jstl</artifactId>
             <version>${jstl.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-text</artifactId>
+            <version>${commons-text.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.apache.tomcat.embed</groupId>
             <artifactId>tomcat-embed-jasper</artifactId>
             <!--uncomment below if deploying in web container -->
             <!--<scope>provided</scope> -->
         </dependency>
+        <!-- devtools enables code hotswap in embedded server -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-devtools</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
@@ -100,6 +110,7 @@
         <jstl.version>1.2</jstl.version>
         <spring-boot.version>2.4.4</spring-boot.version>
         <log4j2.version>2.17.1</log4j2.version>
+        <commons-text.version>1.10.0</commons-text.version>
     </properties>
 
 </project>
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-jsp/src/main/java/com/baeldung/boot/jsp/controller/JSPVariableController.java b/spring-boot-modules/spring-boot-jsp/src/main/java/com/baeldung/boot/jsp/controller/JSPVariableController.java
new file mode 100644
index 0000000000..c85d588c07
--- /dev/null
+++ b/spring-boot-modules/spring-boot-jsp/src/main/java/com/baeldung/boot/jsp/controller/JSPVariableController.java
@@ -0,0 +1,31 @@
+package com.baeldung.boot.jsp.controller;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Controller
+@RequestMapping("/jsp-var")
+public class JSPVariableController {
+
+    @GetMapping("/by-jsp")
+    public String byJsp() {
+        return "/jsp-var/by-jsp";
+    }
+
+    @GetMapping("/by-el")
+    public String byEl() {
+        return "/jsp-var/by-el";
+    }
+
+    @GetMapping("/by-jstl")
+    public String byJstl() {
+        return "/jsp-var/by-jstl";
+    }
+
+    @GetMapping("/to-dom")
+    public String byDom() {
+        return "/jsp-var/to-dom";
+    }
+
+}
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-el.jsp b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-el.jsp
new file mode 100644
index 0000000000..381df4f5eb
--- /dev/null
+++ b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-el.jsp
@@ -0,0 +1,18 @@
+<%@ page import="org.apache.commons.text.StringEscapeUtils" %>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<%
+    String jspMsg = StringEscapeUtils.escapeEcmaScript("Hello! This is Sam's page.");
+    request.setAttribute("jspMsg", jspMsg);
+%>
+<html>
+    <head>
+        <title>Conversion by JSP EL</title>
+        <script type="text/javascript">
+            var jsMsg = '${requestScope.jspMsg}';
+            console.info(jsMsg);
+        </script>
+    </head>
+    <body>
+       <div>Open the browser console to see the message.</div>
+    </body>
+</html>
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jsp.jsp b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jsp.jsp
new file mode 100644
index 0000000000..84c1f0db29
--- /dev/null
+++ b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jsp.jsp
@@ -0,0 +1,16 @@
+<%@ page import="org.apache.commons.text.StringEscapeUtils" %>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<%
+    String jspMsg = StringEscapeUtils.escapeEcmaScript("Hello! This is Sam's page.");
+%>
+<html>
+    <head>
+        <title>Conversion by JSP expression tag</title>
+            var jsMsg = '<%=jspMsg%>';
+            console.info(jsMsg);
+        </script>
+    </head>
+    <body>
+       <div>Open the browser console to see the message.</div>
+    </body>
+</html>
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jstl.jsp b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jstl.jsp
new file mode 100644
index 0000000000..5ac4bc8daa
--- /dev/null
+++ b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/by-jstl.jsp
@@ -0,0 +1,19 @@
+<%@ page import="org.apache.commons.text.StringEscapeUtils" %>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<%
+    String jspMsg = StringEscapeUtils.escapeEcmaScript("Hello! This is Sam's page.");
+    request.setAttribute("scopedMsg", jspMsg);
+%>
+<html>
+    <head>
+        <title>Conversion by JSTL</title>
+        <script type="text/javascript">
+            var jsMsg = '<c:out value="${scopedMsg}" escapeXml="false"/>';
+            console.info(jsMsg);
+        </script>
+    </head>
+    <body>
+       <div>Open the browser console to see the message.</div>
+    </body>
+</html>
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/to-dom.jsp b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/to-dom.jsp
new file mode 100644
index 0000000000..2f44e5e664
--- /dev/null
+++ b/spring-boot-modules/spring-boot-jsp/src/main/webapp/WEB-INF/jsp/jsp-var/to-dom.jsp
@@ -0,0 +1,19 @@
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<%
+    String jspTag = "<h1>Hello</h1>";
+%>
+<html>
+    <head>
+        <title>Convert to an HTML tag</title>
+        <script type="text/javascript">
+            function printTag() {
+                var tags = document.getElementById("fromJspTag").innerHTML;
+                console.info(tags);
+            }
+        </script>
+    </head>
+    <body onLoad="printTag()">
+       <div id="fromJspTag"><%=jspTag%></div>
+       <div>Open the browser console to see the tags.</div>
+    </body>
+</html>
\ No newline at end of file