spring boot 2.x静态资源会被拦截器拦截的原因分析及解决
作者：某某
这篇文章主要介绍了spring boot 2.x静态资源会被拦截器拦截的原因分析及解决，具有很好的参考价值，希望对大家有所帮助。如有错误或未考虑完全的地方，望不吝赐教
spring boot 2.x静态资源会被拦截器拦截的原因
在spring boot 1.5.x中，resources/static目录下的静态资源可以直接访问，并且访问路径上不用带static，比如静态资源放置位置如下图所示：
那么访问静态资源的路径可以是：
http://localhost:8080/views/demoindex.html
http://localhost:8080/res/js/jquery.min.js
当有配置自定义HandlerInterceptor拦截器时，请求以上静态资源路径不会被拦截。
自定义HandlerInterceptor拦截器源码如下
package com.itopener.demo.config;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
/**
* @author fuwei.deng
* @date 2018年4月13日 下午3:32:26
* @version 1.0.0
*/
public class LoginRequiredInterceptor extends HandlerInterceptorAdapter {
private final Logger logger = LoggerFactory.getLogger(LoginRequiredInterceptor.class);
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
logger.info(request.getRequestURI());
return super.preHandle(request, response, handler);
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
logger.info(request.getRequestURI());
super.afterCompletion(request, response, handler, ex);
}
}
配置如下
package com.itopener.demo.config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
/**
* @author fuwei.deng
* @date 2018年4月13日 下午3:32:54
* @version 1.0.0
*/
@Configuration
public class WebMvcConfiguration extends WebMvcConfigurerAdapter {
private final Logger logger = LoggerFactory.getLogger(WebMvcConfiguration.class);
@Override
public void addInterceptors(InterceptorRegistry registry) {
logger.info("add interceptors");
registry.addInterceptor(new LoginRequiredInterceptor());
}
}
访问静态资源时路径上不用加static目录
当spring boot版本升级为2.x时，访问静态资源就会被HandlerInterceptor拦截
这样对于利用HandlerInterceptor来处理访问权限或其他相关的功能就会受影响，跟踪源码查看原因，是因为spring boot 2.x依赖的spring 5.x版本，相对于spring boot 1.5.x依赖的spring 4.3.x版本而言，针对资源的拦截器初始化时有区别
具体源码在WebMvcConfigurationSupport中，spring 4.3.x源码如下：
/**
* Return a handler mapping ordered at Integer.MAX_VALUE-1 with mapped
* resource handlers. To configure resource handling, override
* {@link #addResourceHandlers}.
*/
@Bean
public HandlerMapping resourceHandlerMapping() {
ResourceHandlerRegistry registry = new ResourceHandlerRegistry(this.applicationContext,
this.servletContext, mvcContentNegotiationManager());
addResourceHandlers(registry);
AbstractHandlerMapping handlerMapping = registry.getHandlerMapping();
if (handlerMapping != null) {
handlerMapping.setPathMatcher(mvcPathMatcher());
handlerMapping.setUrlPathHelper(mvcUrlPathHelper());
// 此处固定添加了一个Interceptor
handlerMapping.setInterceptors(new ResourceUrlProviderExposingInterceptor(mvcResourceUrlProvider()));
handlerMapping.setCorsConfigurations(getCorsConfigurations());
}
else {
handlerMapping = new EmptyHandlerMapping();
}
return handlerMapping;
}
而spring 5.x的源码如下：
/**
* Return a handler mapping ordered at Integer.MAX_VALUE-1 with mapped
* resource handlers. To configure resource handling, override
* {@link #addResourceHandlers}.
*/
@Bean
public HandlerMapping resourceHandlerMapping() {
Assert.state(this.applicationContext != null, "No ApplicationContext set");
Assert.state(this.servletContext != null, "No ServletContext set");
ResourceHandlerRegistry registry = new ResourceHandlerRegistry(this.applicationContext,
this.servletContext, mvcContentNegotiationManager(), mvcUrlPathHelper());
addResourceHandlers(registry);
AbstractHandlerMapping handlerMapping = registry.getHandlerMapping();
if (handlerMapping != null) {
handlerMapping.setPathMatcher(mvcPathMatcher());
handlerMapping.setUrlPathHelper(mvcUrlPathHelper());
// 此处是将所有的HandlerInterceptor都添加了（包含自定义的HandlerInterceptor）
handlerMapping.setInterceptors(getInterceptors());
handlerMapping.setCorsConfigurations(getCorsConfigurations());
}
else {
handlerMapping = new EmptyHandlerMapping();
}
return handlerMapping;
}
/**
* Provide access to the shared handler interceptors used to configure
* {@link HandlerMapping} instances with. This method cannot be overridden,
* use {@link #addInterceptors(InterceptorRegistry)} instead.
*/
protected final Object[] getInterceptors() {
if (this.interceptors == null) {
InterceptorRegistry registry = new InterceptorRegistry();
// 此处传入新new的registry对象，在配置类当中设置自定义的HandlerInterceptor后即可获取到
addInterceptors(registry);
registry.addInterceptor(new ConversionServiceExposingInterceptor(mvcConversionService()));
registry.addInterceptor(new ResourceUrlProviderExposingInterceptor(mvcResourceUrlProvider()));
this.interceptors = registry.getInterceptors();
}
return this.interceptors.toArray();
}
从源码当中可以看出，使用spring 5.x时，静态资源也会执行自定义的拦截器，因此在配置拦截器的时候需要指定排除静态资源的访问路径，即配置改为如下即可：
package com.itopener.demo.config;
import java.util.Arrays;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/**
* @author fuwei.deng
* @date 2018年4月13日 下午3:32:54
* @version 1.0.0
*/
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
private final Logger logger = LoggerFactory.getLogger(WebMvcConfiguration.class);
@Override
public void addInterceptors(InterceptorRegistry registry) {
logger.info("add interceptors");
registry.addInterceptor(new LoginRequiredInterceptor()).excludePathPatterns(Arrays.asList("/views/**", "/res/**"));
}
}
这样就可以和spring boot 1.5.x一样的方式使用了。
不过从源码当中可以看出，每个静态资源的请求都会被自定义Interceptor拦截，只是通过访问路径判断后不会执行拦截器的内容，所以spring 5.x相对于spring 4.3.x而言，这部分处理的性能会更低一些
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。