Merge pull request #10736 from wlesniak/master

BAEL-4564 - Difference between Interceptor and Filter in Spring MVC

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/FilterInterceptorApp.java

@@ -0,0 +1,11 @@
+package com.baeldung.filtersinterceptors;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication(scanBasePackages = "com.baeldung.filtersinterceptors")
+public class FilterInterceptorApp {
+    public static void main(String[] args) {
+        SpringApplication.run(FilterInterceptorApp.class, args);
+    }
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/HelloConroller.java

@@ -0,0 +1,19 @@
+package com.baeldung.filtersinterceptors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+@Controller
+public class HelloConroller {
+
+    private Logger logger = LoggerFactory.getLogger(HelloConroller.class);
+
+    @GetMapping("/hello")
+    public String hello() {
+        logger.info("Hello from the controller");
+        return "hello";
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/LogFilter.java

@@ -0,0 +1,26 @@
+package com.baeldung.filtersinterceptors;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class LogFilter implements Filter {
+
+    private Logger logger = LoggerFactory.getLogger(LogFilter.class);
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        logger.info("Hello from: " + request.getLocalAddr());
+        chain.doFilter(request, response);
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/LogInterceptor.java

@@ -0,0 +1,32 @@
+package com.baeldung.filtersinterceptors;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.servlet.ModelAndView;
+
+public class LogInterceptor implements HandlerInterceptor {
+
+    private Logger logger = LoggerFactory.getLogger(LogInterceptor.class);
+
+    @Override
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
+        logger.info("preHandle");
+        return true;
+    }
+
+    @Override
+    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
+        logger.info("postHandle");
+    }
+
+    @Override
+    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
+        logger.info("afterCompletion");
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/WebMvcConfig.java

@@ -0,0 +1,15 @@
+package com.baeldung.filtersinterceptors;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@Configuration
+public class WebMvcConfig implements WebMvcConfigurer {
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(new LogInterceptor());
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/resources/templates/hello.html

@@ -0,0 +1,10 @@
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Spring Filters vs Interceptors</title>
+</head>
+
+<body>
+	<h3>Hello</h3>
+</body>
+</html>