BAEL3771: Cache Headers in Spring MVC

spring-mvc-java/src/main/java/com/baeldung/spring/web/config/WebConfig.java

@@ -2,6 +2,7 @@ package com.baeldung.spring.web.config;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 
 import org.springframework.context.MessageSource;
 import org.springframework.context.annotation.Bean;
@@ -9,15 +10,19 @@ import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Description;
 import org.springframework.context.support.ResourceBundleMessageSource;
+import org.springframework.http.CacheControl;
 import org.springframework.http.MediaType;
 import org.springframework.http.converter.ByteArrayHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
 import org.springframework.web.servlet.config.annotation.PathMatchConfigurer;
 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.handler.BeanNameUrlHandlerMapping;
+import org.springframework.web.servlet.mvc.WebContentInterceptor;
 import org.springframework.web.servlet.view.InternalResourceViewResolver;
 import org.springframework.web.servlet.view.JstlView;
 import org.springframework.web.util.UrlPathHelper;
@@ -30,14 +35,14 @@ import com.baeldung.excel.ExcelPOIHelper;
 
 @EnableWebMvc
 @Configuration
-@ComponentScan(basePackages = { "com.baeldung.web.controller" })
+@ComponentScan(basePackages = {"com.baeldung.web.controller"})
 public class WebConfig implements WebMvcConfigurer {
-	
+
     @Override
     public void addViewControllers(final ViewControllerRegistry registry) {
         registry.addViewController("/").setViewName("index");
     }
-    
+
     @Bean
     public ViewResolver thymeleafViewResolver() {
         final ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
@@ -84,7 +89,10 @@ public class WebConfig implements WebMvcConfigurer {
 
     @Override
     public void addResourceHandlers(final ResourceHandlerRegistry registry) {
-        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
+        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/")
+          .setCacheControl(CacheControl.maxAge(60, TimeUnit.SECONDS)
+                             .noTransform()
+                             .mustRevalidate());
     }
 
     @Override
@@ -121,4 +129,13 @@ public class WebConfig implements WebMvcConfigurer {
     public ExcelPOIHelper excelPOIHelper() {
         return new ExcelPOIHelper();
     }
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        WebContentInterceptor interceptor = new WebContentInterceptor();
+        interceptor.addCacheMapping(CacheControl.maxAge(60, TimeUnit.SECONDS)
+                                      .noTransform()
+                                      .mustRevalidate(), "/cache/*");
+        registry.addInterceptor(interceptor);
+    }
 }

spring-mvc-java/src/main/java/com/baeldung/web/controller/CacheControlController.java

@@ -0,0 +1,55 @@
+package com.baeldung.web.controller;
+
+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/src/test/java/com/baeldung/web/controller/CacheControlControllerIntegrationTest.java

@@ -0,0 +1,84 @@
+package com.baeldung.web.controller;
+
+import com.baeldung.spring.web.config.WebConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpHeaders;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
+import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.context.WebApplicationContext;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+
+import static org.springframework.http.HttpHeaders.IF_UNMODIFIED_SINCE;
+
+@ExtendWith(SpringExtension.class)
+@WebAppConfiguration
+@ContextConfiguration(classes = {WebConfig.class, WebConfig.class})
+public class CacheControlControllerIntegrationTest {
+
+    @Autowired
+    private WebApplicationContext wac;
+
+    private MockMvc mockMvc;
+
+    @BeforeEach
+    void setup() throws Exception {
+        this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build();
+    }
+
+    @Test
+    void whenResponseBody_thenReturnCacheHeader() throws Exception {
+        this.mockMvc.perform(MockMvcRequestBuilders.get("/hello/baeldung"))
+          .andDo(MockMvcResultHandlers.print())
+          .andExpect(MockMvcResultMatchers.status().isOk())
+          .andExpect(MockMvcResultMatchers.header().string("Cache-Control","max-age=60, must-revalidate, no-transform"));
+    }
+
+    @Test
+    void whenViewName_thenReturnCacheHeader() throws Exception {
+        this.mockMvc.perform(MockMvcRequestBuilders.get("/home/baeldung"))
+          .andDo(MockMvcResultHandlers.print())
+          .andExpect(MockMvcResultMatchers.status().isOk())
+          .andExpect(MockMvcResultMatchers.header().string("Cache-Control","max-age=60, must-revalidate, no-transform"))
+          .andExpect(MockMvcResultMatchers.view().name("home"));
+    }
+
+    @Test
+    void whenStaticResources_thenReturnCacheHeader() throws Exception {
+        this.mockMvc.perform(MockMvcRequestBuilders.get("/resources/hello.css"))
+          .andDo(MockMvcResultHandlers.print())
+          .andExpect(MockMvcResultMatchers.status().isOk())
+          .andExpect(MockMvcResultMatchers.header().string("Cache-Control","max-age=60, must-revalidate, no-transform"));
+    }
+
+    @Test
+    void whenInterceptor_thenReturnCacheHeader() throws Exception {
+        this.mockMvc.perform(MockMvcRequestBuilders.get("/cache/baeldung"))
+          .andDo(MockMvcResultHandlers.print())
+          .andExpect(MockMvcResultMatchers.status().isOk())
+          .andExpect(MockMvcResultMatchers.header().string("Cache-Control","max-age=60, must-revalidate, no-transform"));
+    }
+
+    @Test
+    void whenValidate_thenReturnCacheHeader() throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+        headers.add(IF_UNMODIFIED_SINCE, "Tue, 04 Feb 2020 19:57:25 GMT");
+        this.mockMvc.perform(MockMvcRequestBuilders.get("/validate/baeldung").headers(headers))
+          .andDo(MockMvcResultHandlers.print())
+          .andExpect(MockMvcResultMatchers.status().is(304));
+    }
+
+
+
+
+}