Allow JspServlet's init parameters to be configured via the environment

This commit adds support for configuring the JSP servlet’s init
parameters via the environment using server.jsp-servlet.init-parameters.*.
As part of this change the configuration of registerJspServlet and
jspServletClassName have been moved onto a new type, JspServlet, and the
existing setters on ConfigurableEmbeddedServletContainer have been 
deprecated. In addition to providing a model for configuring the JSP
servlet that’s consistent with the model for other configuration (SSL,
for example), this change also means that the class name and whether or
not the servlet is registered at all can now also be configured via the
environment.

Closes spring-projectsgh-2825

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -36,6 +36,7 @@
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.InitParameterConfiguringServletContextInitializer;
+import org.springframework.boot.context.embedded.JspServlet;
 import org.springframework.boot.context.embedded.Ssl;
 import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
 import org.springframework.boot.context.embedded.tomcat.TomcatContextCustomizer;
@@ -92,6 +93,9 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer, Ord
 
 	private final Undertow undertow = new Undertow();
 
+	@NestedConfigurationProperty
+	private JspServlet jspServlet;
+
 	/**
 	 * ServletContext parameters.
 	 */
@@ -110,6 +114,10 @@ public Undertow getUndertow() {
 		return this.undertow;
 	}
 
+	public JspServlet jspServlet() {
+		return this.jspServlet;
+	}
+
 	public String getContextPath() {
 		return this.contextPath;
 	}
@@ -182,6 +190,14 @@ public void setSsl(Ssl ssl) {
 		this.ssl = ssl;
 	}
 
+	public JspServlet getJspServlet() {
+		return this.jspServlet;
+	}
+
+	public void setJspServlet(JspServlet jspServlet) {
+		this.jspServlet = jspServlet;
+	}
+
 	public Map<String, String> getContextParameters() {
 		return this.contextParameters;
 	}
@@ -207,6 +223,9 @@ public void customize(ConfigurableEmbeddedServletContainer container) {
 		if (getSsl() != null) {
 			container.setSsl(getSsl());
 		}
+		if (getJspServlet() != null) {
+			container.setJspServlet(getJspServlet());
+		}
 		if (container instanceof TomcatEmbeddedServletContainerFactory) {
 			getTomcat()
 					.customizeTomcat((TomcatEmbeddedServletContainerFactory) container);
@@ -436,6 +455,13 @@ public void customize(Context context) {
 				}
 			});
 
+			factory.addContextCustomizers(new TomcatContextCustomizer() {
+				@Override
+				public void customize(Context context) {
+					context.setBackgroundProcessorDelay(Tomcat.this.backgroundProcessorDelay);
+				}
+			});
+
 			String remoteIpHeader = getRemoteIpHeader();
 			String protocolHeader = getProtocolHeader();
 			if (StringUtils.hasText(remoteIpHeader)

spring-boot/src/main/java/org/springframework/boot/context/embedded/AbstractConfigurableEmbeddedServletContainer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,12 +26,14 @@
 import java.util.concurrent.TimeUnit;
 
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 
 /**
  * Abstract base class for {@link ConfigurableEmbeddedServletContainer} implementations.
  *
  * @author Phillip Webb
  * @author Dave Syer
+ * @author Andy Wilkinson
  * @see AbstractEmbeddedServletContainerFactory
  */
 public abstract class AbstractConfigurableEmbeddedServletContainer implements
@@ -44,10 +46,6 @@ public abstract class AbstractConfigurableEmbeddedServletContainer implements
 
 	private boolean registerDefaultServlet = true;
 
-	private boolean registerJspServlet = true;
-
-	private String jspServletClassName = "org.apache.jasper.servlet.JspServlet";
-
 	private int port = 8080;
 
 	private List<ServletContextInitializer> initializers = new ArrayList<ServletContextInitializer>();
@@ -64,6 +62,8 @@ public abstract class AbstractConfigurableEmbeddedServletContainer implements
 
 	private Ssl ssl;
 
+	private JspServlet jspServlet = new JspServlet();
+
 	/**
 	 * Create a new {@link AbstractConfigurableEmbeddedServletContainer} instance.
 	 */
@@ -228,18 +228,10 @@ public void setRegisterDefaultServlet(boolean registerDefaultServlet) {
 		this.registerDefaultServlet = registerDefaultServlet;
 	}
 
-	/**
-	 * Flag to indicate that the JSP servlet should be registered if available on the
-	 * classpath.
-	 * @return true if the JSP servlet is to be registered
-	 */
-	public boolean isRegisterJspServlet() {
-		return this.registerJspServlet;
-	}
-
 	@Override
 	public void setRegisterJspServlet(boolean registerJspServlet) {
-		this.registerJspServlet = registerJspServlet;
+		Assert.notNull(this.jspServlet);
+		this.jspServlet.setRegistered(registerJspServlet);
 	}
 
 	/**
@@ -261,14 +253,17 @@ public Ssl getSsl() {
 
 	@Override
 	public void setJspServletClassName(String jspServletClassName) {
-		this.jspServletClassName = jspServletClassName;
+		Assert.notNull(this.jspServlet);
+		this.jspServlet.setClassName(jspServletClassName);
 	}
 
-	/**
-	 * @return the JSP servlet class name
-	 */
-	protected String getJspServletClassName() {
-		return this.jspServletClassName;
+	@Override
+	public void setJspServlet(JspServlet jspServlet) {
+		this.jspServlet = jspServlet;
+	}
+
+	public JspServlet getJspServlet() {
+		return this.jspServlet;
 	}
 
 	/**
@@ -287,4 +282,16 @@ protected final ServletContextInitializer[] mergeInitializers(
 				.toArray(new ServletContextInitializer[mergedInitializers.size()]);
 	}
 
+	/**
+	 * Returns whether or not he JSP servlet should be registered with the embedded
+	 * container.
+	 * @return {@code true} if the container should be registered, otherwise {@code false}
+	 */
+	protected boolean shouldRegisterJspServlet() {
+		return this.jspServlet != null
+				&& this.jspServlet.getRegistered()
+				&& ClassUtils.isPresent(this.jspServlet.getClassName(), getClass()
+						.getClassLoader());
+	}
+
 }

spring-boot/src/main/java/org/springframework/boot/context/embedded/ConfigurableEmbeddedServletContainer.java

@@ -27,6 +27,7 @@
  * {@link EmbeddedServletContainerFactory}.
  *
  * @author Dave Syer
+ * @author Andy Wilkinson
  * @see EmbeddedServletContainerFactory
  * @see EmbeddedServletContainerCustomizer
  */
@@ -76,15 +77,23 @@ public interface ConfigurableEmbeddedServletContainer {
 	 * Tomcat and Jetty use Jasper for their JSP implementation the default is
 	 * <code>org.apache.jasper.servlet.JspServlet</code>.
 	 * @param jspServletClassName the class name for the JSP servlet if used
+	 * @deprecated in 1.3.0 in favor of {@link JspServlet#setClassName(String)}
+	 * @see #setJspServlet
+	 * @see JspServlet#setClassName(String)
 	 */
+	@Deprecated
 	void setJspServletClassName(String jspServletClassName);
 
 	/**
 	 * Set if the JspServlet should be registered if it is on the classpath. Defaults to
 	 * {@code true} so that files from the {@link #setDocumentRoot(File) document root}
 	 * will be served.
 	 * @param registerJspServlet if the JSP servlet should be registered
+	 * @deprecated in 1.3.0 in favor of {@link JspServlet#setRegistered(boolean)}
+	 * @see #setJspServlet
+	 * @see JspServlet#setRegistered(boolean)
 	 */
+	@Deprecated
 	void setRegisterJspServlet(boolean registerJspServlet);
 
 	/**
@@ -146,4 +155,10 @@ public interface ConfigurableEmbeddedServletContainer {
 	 */
 	void setSsl(Ssl ssl);
 
+	/**
+	 * Sets the configuration that will be applied to the container's JSP servlet
+	 * @param jspServlet the JSP servlet configuration
+	 */
+	void setJspServlet(JspServlet jspServlet);
+
 }

spring-boot/src/main/java/org/springframework/boot/context/embedded/JspServlet.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2012-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.context.embedded;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Configuration for the container's JSP servlet.
+ *
+ * @author Andy Wilkinson
+ * @since 1.3.0
+ */
+public class JspServlet {
+
+	/**
+	 * The class name of the servlet to use for JSPs. If registered is true and this class
+	 * is on the classpath then it will be registered. Since both Tomcat and Jetty use
+	 * Jasper for their JSP implementation the default is
+	 * org.apache.jasper.servlet.JspServlet.
+	 */
+	private String className = "org.apache.jasper.servlet.JspServlet";
+
+	/**
+	 * Init parameters use to configure the JSP servlet.
+	 */
+	private Map<String, String> initParameters = new HashMap<String, String>();
+
+	/**
+	 * Whether or not the JSP servlet should be registered with the embedded servlet
+	 * container.
+	 */
+	private boolean registered = true;
+
+	public String getClassName() {
+		return this.className;
+	}
+
+	public void setClassName(String className) {
+		this.className = className;
+	}
+
+	public Map<String, String> getInitParameters() {
+		return this.initParameters;
+	}
+
+	public void setInitParameters(Map<String, String> initParameters) {
+		this.initParameters = initParameters;
+	}
+
+	public boolean getRegistered() {
+		return this.registered;
+	}
+
+	public void setRegistered(boolean registered) {
+		this.registered = registered;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactory.java

@@ -235,9 +235,7 @@ protected final void configureWebAppContext(WebAppContext context,
 		if (isRegisterDefaultServlet()) {
 			addDefaultServlet(context);
 		}
-		if (isRegisterJspServlet()
-				&& ClassUtils.isPresent(getJspServletClassName(), getClass()
-						.getClassLoader())) {
+		if (shouldRegisterJspServlet()) {
 			addJspServlet(context);
 		}
 		ServletContextInitializer[] initializersToUse = mergeInitializers(initializers);
@@ -297,8 +295,9 @@ protected final void addJspServlet(WebAppContext context) {
 		Assert.notNull(context, "Context must not be null");
 		ServletHolder holder = new ServletHolder();
 		holder.setName("jsp");
-		holder.setClassName(getJspServletClassName());
+		holder.setClassName(getJspServlet().getClassName());
 		holder.setInitParameter("fork", "false");
+		holder.setInitParameters(getJspServlet().getInitParameters());
 		holder.setInitOrder(3);
 		context.getServletHandler().addServlet(holder);
 		ServletMapping mapping = new ServletMapping();
@@ -378,7 +377,7 @@ protected void postProcessWebAppContext(WebAppContext webAppContext) {
 	}
 
 	/**
-	 * Factory method called to create the {@link JettyEmbeddedServletContainer}.
+	 * Factory method called to create the {@link JettyEmbeddedServletContainer} .
 	 * Subclasses can override this method to return a different
 	 * {@link JettyEmbeddedServletContainer} or apply additional processing to the Jetty
 	 * server.

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactory.java

@@ -27,6 +27,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
@@ -173,9 +174,7 @@ protected void prepareContext(Host host, ServletContextInitializer[] initializer
 		if (isRegisterDefaultServlet()) {
 			addDefaultServlet(context);
 		}
-		if (isRegisterJspServlet()
-				&& ClassUtils.isPresent(getJspServletClassName(), getClass()
-						.getClassLoader())) {
+		if (shouldRegisterJspServlet()) {
 			addJspServlet(context);
 			addJasperInitializer(context);
 			context.addLifecycleListener(new StoreMergedWebXmlListener());
@@ -202,8 +201,12 @@ private void addDefaultServlet(Context context) {
 	private void addJspServlet(Context context) {
 		Wrapper jspServlet = context.createWrapper();
 		jspServlet.setName("jsp");
-		jspServlet.setServletClass(getJspServletClassName());
+		jspServlet.setServletClass(getJspServlet().getClassName());
 		jspServlet.addInitParameter("fork", "false");
+		for (Entry<String, String> initParameter : getJspServlet().getInitParameters()
+				.entrySet()) {
+			jspServlet.addInitParameter(initParameter.getKey(), initParameter.getValue());
+		}
 		jspServlet.setLoadOnStartup(3);
 		context.addChild(jspServlet);
 		context.addServletMapping("*.jsp", "jsp");

spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainerFactory.java

@@ -110,7 +110,7 @@ public class UndertowEmbeddedServletContainerFactory extends
 	 */
 	public UndertowEmbeddedServletContainerFactory() {
 		super();
-		setRegisterJspServlet(false);
+		getJspServlet().setRegistered(false);
 	}
 
 	/**
@@ -120,7 +120,7 @@ public UndertowEmbeddedServletContainerFactory() {
 	 */
 	public UndertowEmbeddedServletContainerFactory(int port) {
 		super(port);
-		setRegisterJspServlet(false);
+		getJspServlet().setRegistered(false);
 	}
 
 	/**
@@ -131,7 +131,7 @@ public UndertowEmbeddedServletContainerFactory(int port) {
 	 */
 	public UndertowEmbeddedServletContainerFactory(String contextPath, int port) {
 		super(contextPath, port);
-		setRegisterJspServlet(false);
+		getJspServlet().setRegistered(false);
 	}
 
 	/**
@@ -441,12 +441,6 @@ public void setDirectBuffers(Boolean directBuffers) {
 		this.directBuffers = directBuffers;
 	}
 
-	@Override
-	public void setRegisterJspServlet(boolean registerJspServlet) {
-		Assert.isTrue(!registerJspServlet, "Undertow does not support JSPs");
-		super.setRegisterJspServlet(registerJspServlet);
-	}
-
 	/**
 	 * Undertow {@link ResourceManager} for JAR resources.
 	 */