9个SpringBoot中的自带实用过滤器使用详解

# application.properties
server.servlet.encoding.charset=UTF-8
server.servlet.encoding.force=true
server.servlet.encoding.enabled=true

@Bean
public FilterRegistrationBean<CharacterEncodingFilter> characterEncodingFilter() {
    CharacterEncodingFilter filter = new CharacterEncodingFilter();
    filter.setEncoding("UTF-8");
    filter.setForceEncoding(true);
    
    FilterRegistrationBean<CharacterEncodingFilter> registrationBean = new FilterRegistrationBean<>();
    registrationBean.setFilter(filter);
    registrationBean.addUrlPatterns("/*");
    registrationBean.setOrder(Ordered.HIGHEST_PRECEDENCE);
    return registrationBean;
}

# 默认是开启的，如需禁用可设置为false
spring.mvc.hiddenmethod.filter.enabled=true

<form action="/users/123" method="post">
    <input type="hidden" name="_method" value="DELETE"/>
    <button type="submit">删除用户</button>
</form>

@DeleteMapping("/users/{id}")
public String deleteUser(@PathVariable Long id) {
    userService.deleteUser(id);
    return "redirect:/users";
}

spring.mvc.formcontent.filter.enabled=true

@PutMapping("/users/{id}")
public String updateUser(@PathVariable Long id, UserForm form) {
    // 没有FormContentFilter时，form对象的属性将无法被正确填充
    userService.updateUser(id, form);
    return "redirect:/users";
}

@Component
public class RequestInfoService {
    
    public String getClientInfo() {
        ServletRequestAttributes attributes = 
            (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        
        return String.format("Client IP: %s, User-Agent: %s", 
                             request.getRemoteAddr(), 
                             request.getHeader("User-Agent"));
    }
}

@Bean
public CorsFilter corsFilter() {
    CorsConfiguration config = new CorsConfiguration();
    config.setAllowCredentials(true);
    config.addAllowedOrigin("https://example.com");
    config.addAllowedHeader("*");
    config.addAllowedMethod("*");
    
    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    source.registerCorsConfiguration("/api/**", config);
    
    return new CorsFilter(source);
}

spring.web.cors.allowed-origins=https://example.com
spring.web.cors.allowed-methods=GET,POST,PUT,DELETE
spring.web.cors.allowed-headers=Authorization,Content-Type
spring.web.cors.allow-credentials=true

@Bean
public FilterRegistrationBean<ShallowEtagHeaderFilter> shallowEtagHeaderFilter() {
    FilterRegistrationBean<ShallowEtagHeaderFilter> registration = new FilterRegistrationBean<>();
    registration.setFilter(new ShallowEtagHeaderFilter());
    registration.addUrlPatterns("/api/*");
    registration.setName("shallowEtagHeaderFilter");
    return registration;
}

@Bean
public FilterRegistrationBean<ForwardedHeaderFilter> forwardedHeaderFilter() {
    FilterRegistrationBean<ForwardedHeaderFilter> registration = new FilterRegistrationBean<>();
    registration.setFilter(new ForwardedHeaderFilter());
    registration.setOrder(Ordered.HIGHEST_PRECEDENCE);
    return registration;
}

@Configuration
public class WebConfig implements WebMvcConfigurer {
    
    @Bean
    public ResourceUrlEncodingFilter resourceUrlEncodingFilter() {
        return new ResourceUrlEncodingFilter();
    }
    
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**")
                .addResourceLocations("classpath:/static/")
                .setCachePeriod(3600)
                .resourceChain(true)
                .addResolver(new VersionResourceResolver()
                        .addContentVersionStrategy("/**"));
    }
}

<!-- Thymeleaf -->
<link rel="stylesheet" th:href="@{/resources/css/main.css}" rel="external nofollow" />

<!-- 渲染后可能变为 -->
<link rel="stylesheet" href="/resources/css/main-d41d8cd98f00b204e9800998ecf8427e.css" rel="external nofollow" />