Spring Web Contexts (BAEL-82) (#2113)

* spring web contexts example

* applicationContext util added

* java based configuration added

* bean name fixed

spring-all/src/main/java/com/baeldung/contexts/Greeting.java

@@ -0,0 +1,19 @@
+package com.baeldung.contexts;
+
+public class Greeting {
+    
+    private String message;
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+    @Override
+    public String toString() {
+        return "Greeting [message=" + message + "]";
+    }
+}

spring-all/src/main/java/com/baeldung/contexts/config/ApplicationInitializer.java

@@ -0,0 +1,35 @@
+package com.baeldung.contexts.config;
+
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRegistration;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.WebApplicationInitializer;
+import org.springframework.web.context.ContextLoaderListener;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+import org.springframework.web.servlet.DispatcherServlet;
+
+@Configuration
+public class ApplicationInitializer implements WebApplicationInitializer {
+
+    @Override
+    public void onStartup(ServletContext servletContext) throws ServletException {
+        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
+        rootContext.register(RootApplicationConfig.class);
+        servletContext.addListener(new ContextLoaderListener(rootContext));
+        
+        AnnotationConfigWebApplicationContext normalWebAppContext = new AnnotationConfigWebApplicationContext();
+        normalWebAppContext.register(NormalWebAppConfig.class);
+        ServletRegistration.Dynamic normal = servletContext.addServlet("normal-webapp", new DispatcherServlet(normalWebAppContext));
+        normal.setLoadOnStartup(1);
+        normal.addMapping("/api/*");
+        
+        AnnotationConfigWebApplicationContext secureWebAppContext = new AnnotationConfigWebApplicationContext();
+        secureWebAppContext.register(SecureWebAppConfig.class);
+        ServletRegistration.Dynamic secure = servletContext.addServlet("secure-webapp", new DispatcherServlet(secureWebAppContext));
+        secure.setLoadOnStartup(1);
+        secure.addMapping("/s/api/*");
+    }
+
+}

spring-all/src/main/java/com/baeldung/contexts/config/NormalWebAppConfig.java

@@ -0,0 +1,25 @@
+package com.baeldung.contexts.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.ViewResolver;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
+import org.springframework.web.servlet.view.InternalResourceViewResolver;
+import org.springframework.web.servlet.view.JstlView;
+
+@Configuration
+@EnableWebMvc
+@ComponentScan(basePackages = { "com.baeldung.contexts.normal" })
+public class NormalWebAppConfig extends WebMvcConfigurerAdapter {
+
+    @Bean
+    public ViewResolver viewResolver() {
+        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
+        resolver.setPrefix("/WEB-INF/view/");
+        resolver.setSuffix(".jsp");
+        resolver.setViewClass(JstlView.class);
+        return resolver;
+    }
+}

spring-all/src/main/java/com/baeldung/contexts/config/RootApplicationConfig.java

@@ -0,0 +1,19 @@
+package com.baeldung.contexts.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+
+import com.baeldung.contexts.Greeting;
+
+@Configuration
+@ComponentScan(basePackages = { "com.baeldung.contexts.services" })
+public class RootApplicationConfig {
+
+    @Bean
+    public Greeting greeting() {
+        Greeting greeting = new Greeting();
+        greeting.setMessage("Hello World !!");
+        return greeting;
+    }
+}

spring-all/src/main/java/com/baeldung/contexts/config/SecureWebAppConfig.java

@@ -0,0 +1,25 @@
+package com.baeldung.contexts.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.ViewResolver;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
+import org.springframework.web.servlet.view.InternalResourceViewResolver;
+import org.springframework.web.servlet.view.JstlView;
+
+@Configuration
+@EnableWebMvc
+@ComponentScan(basePackages = { "com.baeldung.contexts.secure" })
+public class SecureWebAppConfig extends WebMvcConfigurerAdapter {
+        
+    @Bean
+    public ViewResolver viewResolver() {
+        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
+        resolver.setPrefix("/WEB-INF/secure/view/");
+        resolver.setSuffix(".jsp");
+        resolver.setViewClass(JstlView.class);
+        return resolver;
+    }
+}

spring-all/src/main/java/com/baeldung/contexts/normal/HelloWorldController.java

@@ -0,0 +1,41 @@
+package com.baeldung.contexts.normal;
+
+import java.util.Arrays;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.context.ContextLoader;
+import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.servlet.ModelAndView;
+
+import com.baeldung.contexts.services.ApplicationContextUtilService;
+import com.baeldung.contexts.services.GreeterService;
+
+@Controller
+public class HelloWorldController {
+
+    @Autowired
+    WebApplicationContext webApplicationContext;
+
+    @Autowired
+    private GreeterService greeterService;
+    
+    private void processContext() {
+        WebApplicationContext rootContext = ContextLoader.getCurrentWebApplicationContext();
+        
+        System.out.println("root context : " + rootContext);
+        System.out.println("root context Beans: " + Arrays.asList(rootContext.getBeanDefinitionNames()));
+
+        System.out.println("context : " + webApplicationContext);
+        System.out.println("context Beans: " + Arrays.asList(webApplicationContext.getBeanDefinitionNames()));
+    }
+
+    @RequestMapping(path = "/welcome")
+    public ModelAndView helloWorld() {
+        processContext();
+        String message = "<br><div style='text-align:center;'>" + "<h3> " + greeterService.greet() + "</h3></div>";
+        return new ModelAndView("welcome", "message", message);
+    }
+}

spring-all/src/main/java/com/baeldung/contexts/secure/HelloWorldSecureController.java

@@ -0,0 +1,49 @@
+package com.baeldung.contexts.secure;
+
+import java.util.Arrays;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.context.ApplicationContext;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.context.ContextLoader;
+import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.servlet.ModelAndView;
+
+import com.baeldung.contexts.services.ApplicationContextUtilService;
+import com.baeldung.contexts.services.GreeterService;
+
+@Controller
+public class HelloWorldSecureController {
+
+    @Autowired
+    WebApplicationContext webApplicationContext;
+
+    @Autowired
+    private GreeterService greeterService;
+    
+    @Autowired
+    @Qualifier("contextAware")
+    private ApplicationContextUtilService contextUtilService; 
+
+    private void processContext() {
+        ApplicationContext context = contextUtilService.getApplicationContext();
+        System.out.println("application context : " + context);
+        System.out.println("application context Beans: " + Arrays.asList(context.getBeanDefinitionNames()));
+        
+        WebApplicationContext rootContext = ContextLoader.getCurrentWebApplicationContext();
+        System.out.println("context : " + rootContext);
+        System.out.println("context Beans: " + Arrays.asList(rootContext.getBeanDefinitionNames()));
+
+        System.out.println("context : " + webApplicationContext);
+        System.out.println("context Beans: " + Arrays.asList(webApplicationContext.getBeanDefinitionNames()));
+    }
+
+    @RequestMapping(path = "/welcome")
+    public ModelAndView helloWorld() {
+        processContext();
+        String message = "<br><div style='text-align:center;'>" + "<h3> " + greeterService.greet() + "</h3></div>";
+        return new ModelAndView("welcome", "message", message);
+    }
+}

spring-all/src/main/java/com/baeldung/contexts/services/ApplicationContextUtilService.java

@@ -0,0 +1,21 @@
+package com.baeldung.contexts.services;
+
+import org.springframework.beans.BeansException;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.stereotype.Service;
+
+@Service(value="contextAware")
+public class ApplicationContextUtilService implements ApplicationContextAware {
+    
+    private ApplicationContext applicationContext;
+    
+    @Override
+    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+        this.applicationContext = applicationContext;
+    }
+
+    public ApplicationContext getApplicationContext() {
+        return applicationContext;
+    }    
+}

spring-all/src/main/java/com/baeldung/contexts/services/GreeterService.java

@@ -0,0 +1,19 @@
+package com.baeldung.contexts.services;
+
+import javax.annotation.Resource;
+
+import org.springframework.stereotype.Service;
+
+import com.baeldung.contexts.Greeting;
+
+@Service
+public class GreeterService {
+    
+    @Resource
+    private Greeting greeting;
+    
+    public String greet(){
+        return greeting.getMessage();
+    }
+    
+}

spring-all/src/main/webapp/WEB-INF/index.jsp

@@ -0,0 +1,5 @@
+<html>
+<body>
+<h2>Hello World!</h2>
+</body>
+</html>

spring-all/src/main/webapp/WEB-INF/normal-webapp-servlet.xml

@@ -0,0 +1,19 @@
+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="
+        http://www.springframework.org/schema/beans     
+        http://www.springframework.org/schema/beans/spring-beans.xsd
+        http://www.springframework.org/schema/mvc 
+        http://www.springframework.org/schema/mvc/spring-mvc.xsd
+        http://www.springframework.org/schema/context 
+        http://www.springframework.org/schema/context/spring-context.xsd">
+
+	<context:component-scan base-package="com.baeldung.contexts.normal" />
+
+	<bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
+		<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
+		<property name="prefix" value="/WEB-INF/view/" />
+		<property name="suffix" value=".jsp" />
+	</bean>
+</beans>

spring-all/src/main/webapp/WEB-INF/rootApplicationContext.xml

@@ -0,0 +1,16 @@
+<?xml version = "1.0" encoding = "UTF-8"?>
+
+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+	xmlns:context="http://www.springframework.org/schema/context"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans
+   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
+   http://www.springframework.org/schema/context
+   http://www.springframework.org/schema/context/spring-context-3.0.xsd">
+
+	<context:component-scan base-package="com.baeldung.contexts.services" />
+	
+	<bean id="greeting" class="ccom.baeldung.contexts.Greeting">
+		<property name="message" value="Hello World !!" />
+	</bean>
+</beans>

spring-all/src/main/webapp/WEB-INF/secure-webapp-servlet.xml

@@ -0,0 +1,19 @@
+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="
+        http://www.springframework.org/schema/beans     
+        http://www.springframework.org/schema/beans/spring-beans.xsd
+        http://www.springframework.org/schema/mvc 
+        http://www.springframework.org/schema/mvc/spring-mvc.xsd
+        http://www.springframework.org/schema/context 
+        http://www.springframework.org/schema/context/spring-context.xsd">
+
+	<context:component-scan base-package="com.baeldung.contexts.secure" />
+
+	<bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
+		<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
+		<property name="prefix" value="/WEB-INF/secure/view/" />
+		<property name="suffix" value=".jsp" />
+	</bean>
+</beans>

spring-all/src/main/webapp/WEB-INF/secure/view/welcome.jsp

@@ -0,0 +1,11 @@
+<html>
+<head>
+	<title>Spring Web Contexts</title>
+</head>
+<body>
+	<br>
+	<div style="padding: 10px; border-radius: 10px; font-size: 30px; text-align: center;">
+		Secure Web Application : ${message}
+	</div>
+</body>
+</html>

spring-all/src/main/webapp/WEB-INF/view/welcome.jsp

@@ -0,0 +1,11 @@
+<html>
+<head>
+	<title>Spring Web Contexts</title>
+</head>
+<body>
+	<br>
+	<div style="padding: 10px; border-radius: 10px; font-size: 30px; text-align: center;">
+		Normal Web Application : ${message}
+	</div>
+</body>
+</html>

spring-all/src/main/webapp/WEB-INF/web.xml

@@ -4,6 +4,47 @@
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">
 	
+	 <!-- load root application context -->
+  	<context-param>
+    	<param-name>contextConfigLocation</param-name>
+    	<param-value>/WEB-INF/rootApplicationContext.xml</param-value>
+	</context-param>
+	<listener>
+   		<listener-class>
+        	org.springframework.web.context.ContextLoaderListener
+   		</listener-class>
+	</listener> 
+	
+	<!-- secure web app context -->
+    <servlet>
+        <servlet-name>secure-webapp</servlet-name>
+        	<servlet-class>
+            	org.springframework.web.servlet.DispatcherServlet
+        	</servlet-class>
+		    <load-on-startup>1</load-on-startup>
+			<init-param>
+				<param-name>contextConfigLocation</param-name>
+				<param-value>/WEB-INF/secure-webapp-servlet.xml</param-value>
+			</init-param>
+    </servlet>
+    <servlet-mapping>
+        <servlet-name>secure-webapp</servlet-name>
+        <url-pattern>/s/api/*</url-pattern>
+    </servlet-mapping>
+    
+    <!-- normal web app context -->
+    <servlet>
+        <servlet-name>normal-webapp</servlet-name>
+        <servlet-class>
+            org.springframework.web.servlet.DispatcherServlet
+        </servlet-class>
+        <load-on-startup>1</load-on-startup>
+    </servlet>
+    <servlet-mapping>
+        <servlet-name>normal-webapp</servlet-name>
+        <url-pattern>/api/*</url-pattern>
+    </servlet-mapping>
+	
     <servlet>
         <servlet-name>test-mvc</servlet-name>
         <servlet-class>

spring-all/src/main/webapp/index.jsp

@@ -0,0 +1,5 @@
+<html>
+<body>
+<h2>Hello World!</h2>
+</body>
+</html>