java如何在SpringMVC中设置缓存头？

Question

在基于注释的SpringMVC控制器中，为特定路径设置缓存头的首选方法是什么

Answer 1

org.springframework.web.servlet.support.WebContentGenerator是所有Spring控制器的基类，它有许多处理缓存头的方法：

/* Set whether to use the HTTP 1.1 cache-control header. Default is "true".
 * <p>Note: Cache headers will only get applied if caching is enabled
 * (or explicitly prevented) for the current request. */
public final void setUseCacheControlHeader();

/* Return whether the HTTP 1.1 cache-control header is used. */
public final boolean isUseCacheControlHeader();

/* Set whether to use the HTTP 1.1 cache-control header value "no-store"
 * when preventing caching. Default is "true". */
public final void setUseCacheControlNoStore(boolean useCacheControlNoStore);

/* Cache content for the given number of seconds. Default is -1,
 * indicating no generation of cache-related headers.
 * Only if this is set to 0 (no cache) or a positive value (cache for
 * this many seconds) will this class generate cache headers.
 * The headers can be overwritten by subclasses, before content is generated. */
public final void setCacheSeconds(int seconds);

它们可以在生成内容之前在控制器内调用，也可以在Spring上下文中指定为bean属性

Answer 2

您可以使用处理程序拦截器并使用它提供的postHandle方法：

http://static.springsource.org/spring/docs/2.0.x/api/org/springframework/web/servlet/HandlerInterceptor.html

postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) 

然后只需在方法中添加一个标题，如下所示：

response.setHeader("Cache-Control", "no-cache");

Answer 3

您可以为此定义一个地址：@CacheControl(isPublic = true, maxAge = 300, sMaxAge = 300)，然后使用Spring MVC拦截器将此地址呈现到HTTP头。或者做动态的：

int age = calculateLeftTiming();
String cacheControlValue = CacheControlHeader.newBuilder()
      .setCacheType(CacheType.PUBLIC)
      .setMaxAge(age)
      .setsMaxAge(age).build().stringValue();
if (StringUtils.isNotBlank(cacheControlValue)) {
    response.addHeader("Cache-Control", cacheControlValue);
}

可在此处找到含义：优雅的Builder模式

顺便说一句：我刚刚发现Spring MVC内置了对缓存控制的支持： Google WebContent Interceptor或CacheControlHandlerInterceptor或CacheControl，您将找到它

Answer 4

答案很简单：

^{pr1}$ 上面的代码正好显示了您想要实现的目标。你必须做两件事。添加“final HttpServletResponse”作为参数。然后将标头缓存控制设置为无缓存。

Answer 5

我只是遇到了同样的问题，并且找到了框架已经提供的一个很好的解决方案。org.springframework.web.servlet.mvc.WebContentInterceptor类允许您定义默认缓存行为，以及特定于路径的重写（与其他地方使用的路径匹配器行为相同）。我的步骤是：

1. 确保我的org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter实例未设置“cacheSeconds”属性

2. 添加WebContentInterceptor的实例：

   <mvc:interceptors>
   ...
   <bean class="org.springframework.web.servlet.mvc.WebContentInterceptor" p:cacheSeconds="0" p:alwaysUseFullPath="true" >
       <property name="cacheMappings">
           <props>
               <!-- cache for one month -->
               <prop key="/cache/me/**">2592000</prop>
               <!-- don't set cache headers -->
               <prop key="/cache/agnostic/**">-1</prop>
           </props>
       </property>
   </bean>
   ...
   </mvc:interceptors>
   

在这些更改之后，/foo下的响应包含阻止缓存的标题，/cache/me下的响应包含鼓励缓存的标题，/cache/agnostic下的响应不包含与缓存相关的标题

---

如果使用纯Java配置：

@EnableWebMvc
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
  /* Time, in seconds, to have the browser cache static resources (one week). */
  private static final int BROWSER_CACHE_CONTROL = 604800;

  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
    registry
     .addResourceHandler("/images/**")
     .addResourceLocations("/images/")
     .setCachePeriod(BROWSER_CACHE_CONTROL);
  }
}

另见：http://docs.spring.io/spring-security/site/docs/current/reference/html/headers.html

Answer 6

从Spring 4.2开始，您可以执行以下操作：

import org.springframework.http.CacheControl;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.util.concurrent.TimeUnit;

@RestController
public class CachingController {
    @RequestMapping(method = RequestMethod.GET, path = "/cachedapi")
    public ResponseEntity<MyDto> getPermissions() {

        MyDto body = new MyDto();

        return ResponseEntity.ok()
            .cacheControl(CacheControl.maxAge(20, TimeUnit.SECONDS))
            .body(body);
    }
}

CacheControl对象是一个具有许多配置选项的构建器，请参见JavaDoc