add exception handler

Author: destan

pom.xml

@@ -2,9 +2,9 @@
          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.kodgemisi</groupId>
+    <groupId>com.github.kodgemisi</groupId>
     <artifactId>servlet-url-mapper</artifactId>
-    <version>1.0.1</version>
+    <version>1.1.0</version>
     <packaging>jar</packaging>
 
     <organization>

src/main/java/com/kodgemisi/servlet_url_mapping/ExceptionHandler.java

@@ -0,0 +1,17 @@
+package com.kodgemisi.servlet_url_mapping;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Handles any exception during doXXX methods of {@link MappingServlet}. {@link MappingServlet} uses
+ * {@link LoggingExceptionHandler} as default implementation.
+ *
+ * @see LoggingExceptionHandler
+ */
+@FunctionalInterface
+public interface ExceptionHandler {
+
+    void handleException(HttpServletRequest request, HttpServletResponse response, Exception e);
+
+}

src/main/java/com/kodgemisi/servlet_url_mapping/LoggingExceptionHandler.java

@@ -0,0 +1,21 @@
+package com.kodgemisi.servlet_url_mapping;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Logs and rethrows any uncaught exception wrapped in a RuntimeException.
+ */
+public class LoggingExceptionHandler implements ExceptionHandler {
+
+    private static final Logger log = LoggerFactory.getLogger(LoggingExceptionHandler.class);
+
+    @Override
+    public void handleException(HttpServletRequest request, HttpServletResponse response, Exception e) {
+        log.error(e.getMessage(), e);
+        throw new RuntimeException(e);
+    }
+}

src/main/java/com/kodgemisi/servlet_url_mapping/MappingServlet.java

@@ -64,6 +64,11 @@ public class MappingServlet extends HttpServlet {
 	 */
 	protected final ServletUrlPatternRegistrar urlMappingRegistrar;
 
+	/**
+	 * Default is {@link LoggingExceptionHandler}
+	 */
+	protected final ExceptionHandler exceptionHandler;
+
 	public MappingServlet() {
 		this(true);
 	}
@@ -75,70 +80,62 @@ public MappingServlet() {
 	 *                              <a href="http://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.html#setUseTrailingSlashMatch-boolean-">Spring API</a>
 	 */
 	public MappingServlet(boolean useTrailingSlashMatch) {
+		this(new LoggingExceptionHandler(), useTrailingSlashMatch);
+	}
+
+	public MappingServlet(ExceptionHandler exceptionHandler, boolean useTrailingSlashMatch) {
 		this.urlMappingRegistrar = new ServletUrlPatternRegistrar(useTrailingSlashMatch);
+		this.exceptionHandler = exceptionHandler;
 	}
 
 	@Override
 	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
-
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
-		}
+		doCommon(request, response);
 	}
 
 	@Override
 	protected void doHead(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
-
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
-		}
+		doCommon(request, response);
 	}
 
 	@Override
 	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
-
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
-		}
+		doCommon(request, response);
 	}
 
 	@Override
 	protected void doPut(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
-
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
-		}
+		doCommon(request, response);
 	}
 
 	@Override
 	protected void doDelete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
-
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
-		}
+		doCommon(request, response);
 	}
 
 	@Override
 	protected void doOptions(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
-
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
-		}
+		doCommon(request, response);
 	}
 
 	@Override
 	protected void doTrace(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		final ServletUrl servletUrl = urlMappingRegistrar.handle(request, response);
+		doCommon(request, response);
+	}
+
+	private void doCommon(HttpServletRequest request, HttpServletResponse response) {
+		final ServletUrl servletUrl;
+		try {
+			servletUrl = urlMappingRegistrar.handle(request, response);
 
-		if (servletUrl.is404()) {
-			response.sendError(HttpServletResponse.SC_NOT_FOUND);
+			if (servletUrl.is404()) {
+				response.sendError(HttpServletResponse.SC_NOT_FOUND);
+			}
 		}
+		catch (Exception e) {
+			this.exceptionHandler.handleException(request, response, e);
+		}
+
 	}
 
 }