java - 如何在 Spring Boot 中将 Cache-Control header 添加到静态资源？

Question

如何在 Spring Boot 中为静态资源添加 Cache-Control HTTP header ？

尝试在应用程序中使用过滤器组件，该组件正确写入 header ，但 Cache-Control header 被覆盖。

@Component
public class CacheBustingFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) 
                                              throws IOException, ServletException {

        HttpServletResponse httpResp = (HttpServletResponse) resp;
        httpResp.setHeader("Cache-Control", "no-cache, no-store, must-revalidate");
        httpResp.setHeader("This-Header-Is-Set", "no-cache, no-store, must-revalidate");
        httpResp.setHeader("Expires", "0");

        chain.doFilter(req, resp);
    }

我在浏览器中得到的是:

Cache-Control:no-store
This-Header-Is-Set:no-cache, no-store, must-revalidate
Expires:0

我想要的是:

Cache-Control:no-cache, no-store, must-revalidate
This-Header-Is-Set:no-cache, no-store, must-revalidate
Expires:0

Answer 1

这是因为 Spring Security:它重写了所有缓存头以完全禁用缓存。所以我们需要做两件事:

1. 为静态资源禁用 Spring Security
2. 启用静态资源缓存处理

在当前版本的 Spring Boot 中，我们可以在 application.properties 配置中更改此行为。

对某些资源禁用 spring 安全性:

# Comma-separated list of paths to exclude from the default secured 
security.ignored=/myAssets/**

为静态资源启用发送缓存头:

# Enable HTML5 application cache manifest rewriting.
spring.resources.chain.html-application-cache=true

# Enable the Spring Resource Handling chain. Disabled by default unless at least one strategy has been enabled.
spring.resources.chain.enabled=true
# Enable the content Version Strategy.
spring.resources.chain.strategy.content.enabled=true 
# Comma-separated list of patterns to apply to the Version Strategy.
spring.resources.chain.strategy.content.paths=/** 

# Locations of static resources.
spring.resources.static-locations=classpath:/META-INF/resources/,classpath:/resources/,classpath:/static/,classpath:/public/

就是这样。现在 Spring 将检查您的静态文件是否已更改，并可以发送更智能的响应(If-Modiffied-Since 等)并重写您的应用缓存。

此外，如果有理由不为某些资源使用基于内容的版本 - 您可以使用备用 FixedVersion 策略并在配置中明确设置版本:

#Enable the fixed Version Strategy.
spring.resources.chain.strategy.fixed.enabled=false 
# Comma-separated list of patterns to apply to the Version Strategy.
spring.resources.chain.strategy.fixed.paths= 
# Version string to use for the Version Strategy.
spring.resources.chain.strategy.fixed.version= 

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