BAEL3771 Cache Headers in Spring MVC (#8682)

* BAEL3771: Cache Headers in Spring MVC

* BEAL3771: Cache Headers in Spring MVC

* BEAL3771: Cache Headers in Spring MVC

spring-mvc-java-2/src/main/java/com/baeldung/cache/CacheControlController.java

@@ -0,0 +1,55 @@
+package com.baeldung.cache;
+
+import org.springframework.http.CacheControl;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.context.request.WebRequest;
+
+import javax.servlet.http.HttpServletResponse;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.concurrent.TimeUnit;
+
+@Controller
+public class CacheControlController {
+
+    @RequestMapping(value = "/hello/{name}", method = RequestMethod.GET)
+    public ResponseEntity<String> helloWorld(@PathVariable String name) {
+        CacheControl cacheControl = CacheControl.maxAge(60, TimeUnit.SECONDS)
+                                      .noTransform()
+                                      .mustRevalidate();
+        return ResponseEntity.ok()
+                .cacheControl(cacheControl)
+                .body("Hello " + name);
+    }
+
+    @RequestMapping(value = "/home/{name}", method = RequestMethod.GET)
+    public String home(@PathVariable String name, final HttpServletResponse response) {
+        response.addHeader("Cache-Control", "max-age=60, must-revalidate, no-transform");
+        return "home";
+    }
+
+    @RequestMapping(value = "/cache/{name}", method = RequestMethod.GET)
+    public ResponseEntity<String> intercept(@PathVariable String name) {
+        return ResponseEntity.ok().body("Hello " + name);
+    }
+
+    @RequestMapping(value = "/validate/{name}", method = RequestMethod.GET)
+    public ResponseEntity<String> validate(@PathVariable String name, WebRequest request) {
+
+        ZoneId zoneId = ZoneId.of("GMT");
+        long lastModifiedTimestamp = LocalDateTime.of(2020, 02, 4, 19, 57, 45)
+          .atZone(zoneId).toInstant().toEpochMilli();
+
+        if (request.checkNotModified(lastModifiedTimestamp)) {
+            return ResponseEntity.status(304).build();
+        }
+
+        return ResponseEntity.ok().body("Hello " + name);
+    }
+
+
+}

spring-mvc-java-2/src/main/java/com/baeldung/cache/WebConfig.java

@@ -0,0 +1,41 @@
+package com.baeldung.cache;
+
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.CacheControl;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
+import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+import org.springframework.web.servlet.mvc.WebContentInterceptor;
+
+import java.util.concurrent.TimeUnit;
+
+@EnableWebMvc
+@Configuration
+@ComponentScan(basePackages = {"com.baeldung.cache"})
+public class WebConfig implements WebMvcConfigurer {
+
+    @Override
+    public void addViewControllers(final ViewControllerRegistry registry) {
+        registry.addViewController("/").setViewName("index");
+    }
+
+    @Override
+    public void addResourceHandlers(final ResourceHandlerRegistry registry) {
+        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/")
+          .setCacheControl(CacheControl.maxAge(60, TimeUnit.SECONDS)
+            .noTransform()
+            .mustRevalidate());
+    }
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        WebContentInterceptor interceptor = new WebContentInterceptor();
+        interceptor.addCacheMapping(CacheControl.maxAge(60, TimeUnit.SECONDS)
+          .noTransform()
+          .mustRevalidate(), "/cache/*");
+        registry.addInterceptor(interceptor);
+    }
+}