Context and Servlet Initialization Parameters

javax-servlet-init-params/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.javax-servlet-init-params</groupId>
+    <artifactId>javax-servlet-init-params</artifactId>
+    <version>1.0</version>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+   </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+         <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.9.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-core</artifactId>
+            <version>1.3</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>2.18.3</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>javax</groupId>
+            <artifactId>javaee-web-api</artifactId>
+            <version>7.0</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>jstl</groupId>
+            <artifactId>jstl</artifactId>
+            <version>1.2</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.el</groupId>
+            <artifactId>el-api</artifactId>
+            <version>2.2</version>
+        </dependency>
+    </dependencies>                        
+</project>

javax-servlet-init-params/src/main/java/com/baeldung/servlets/UserServlet.java

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+package com.baeldung.servlets;
+
+import java.io.IOException;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebInitParam;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(name = "UserServlet", urlPatterns = {"/userServlet"}, initParams={
+    @WebInitParam(name="name", value="Not provided"), 
+    @WebInitParam(name="email", value="Not provided")})
+public class UserServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+        processRequest(request, response);
+        forwardRequest(request, response, "/WEB-INF/jsp/result.jsp");
+    }
+
+    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+        request.setAttribute("name", getRequestParameter(request, "name"));
+        request.setAttribute("email", getRequestParameter(request, "email"));
+        request.setAttribute("province", getContextParameter("province"));
+        request.setAttribute("country", getContextParameter("country"));
+    }
+
+    protected String getRequestParameter(HttpServletRequest request, String name) {
+        String param = request.getParameter(name);
+        return !param.isEmpty() ? param : getInitParameter(name);
+    }
+
+    protected String getContextParameter(String name) {
+        return getServletContext().getInitParameter(name);
+    }
+
+    protected void forwardRequest(HttpServletRequest request, HttpServletResponse response, String path) 
+            throws ServletException, IOException {
+        request.getRequestDispatcher(path).forward(request, response);
+    }
+}

javax-servlet-init-params/src/main/webapp/WEB-INF/jsp/result.jsp

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+<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
+<%@ page contentType="text/html" pageEncoding="UTF-8"%>
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+        <title>User Data</title>
+    </head>
+    <body>
+        <h2>User Information</h2>
+        <p><strong>Name:</strong> ${name}</p>
+        <p><strong>Email:</strong> ${email}</p>
+        <p><strong>Province:</strong> ${province}</p>
+        <p><strong>Country:</strong> ${country}</p>
+    </body>
+</html>

javax-servlet-init-params/src/main/webapp/WEB-INF/web.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
+         version="3.1">
+    <context-param>
+        <param-name>province</param-name>
+        <param-value>Mendoza</param-value>
+    </context-param>
+    <context-param>
+        <param-name>country</param-name>
+        <param-value>Argentina</param-value>
+    </context-param>
+</web-app>

javax-servlet-init-params/src/main/webapp/index.jsp

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+<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
+<%@ page contentType="text/html" pageEncoding="UTF-8"%>
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Context and Initialization Servlet Parameters</title>
+        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    </head>
+    <body>
+        <h2>Please fill the form below:</h2>
+        <form action="${pageContext.request.contextPath}/userServlet" method="post">
+            <label for="name"><strong>Name:</strong></label>
+            <input type="text" name="name" id="name">
+            <label for="email"><strong>Email:</strong></label>
+            <input type="text" name="email" id="email">
+            <input type="submit" value="Send">
+        </form>
+    </body>
+</html>

javax-servlet-init-params/src/test/java/com/baeldung/test/UserServletUnitTest.java

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+package com.baeldung.test;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import static org.mockito.Mockito.atLeast;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class UserServletUnitTest {
+
+    private static HttpServletRequest request;
+    private static HttpServletResponse response;
+
+
+    @BeforeClass
+    public static void setUpHttpServletRequestMockInstance() {
+        request = mock(HttpServletRequest.class); 
+    }
+
+    @BeforeClass
+    public static void setUpHttpServletResponsetMockInstance() {
+        response = mock(HttpServletResponse.class); 
+    }
+
+    @Test
+    public void givenHttpServletRequestMockInstance_whenCalledgetParameter_thenCalledAtLeastOnce() {
+        request.getParameter("name");
+        verify(request, atLeast(1)).getParameter("name");
+    }
+
+    @Test
+    public void givenHttpServletRequestMockInstance_whenCalledgetParameter_thenOneAssertion() {  
+        when(request.getParameter("name")).thenReturn("username");
+        assertThat(request.getParameter("name")).isEqualTo("username");
+    }
+
+    @Test
+    public void givenHttpServletResponseMockInstance_whenCalledgetContentType_thenCalledAtLeastOnce() {
+        response.getContentType();
+        verify(response, atLeast(1)).getContentType();
+    }
+
+    @Test
+    public void givenHttpServletResponseMockInstance_whenCalledgetContentType_thenOneAssertion() {
+        when(response.getContentType()).thenReturn("text/html");
+        assertThat(response.getContentType()).isEqualTo("text/html");
+    }
+}