SpringBoot2.0以上静态资源会被拦截器拦截的原因和解决方法

项目结构图如下 SpringBoot2.0以上静态资源会被拦截器拦截的原因和解决方法 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.atguigu.springboot04.component;


import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginHandlerInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Object user = request.getSession().getAttribute("loginUser");
        if(user==null){
            //未登录
            request.setAttribute("msg","没有权限请先登陆");
            request.getRequestDispatcher("/index.html").forward(request,response);
            return false;
        }else {
            //登陆
            return true;
        }

    }
}

配置如下

package com.atguigu.springboot04.config;

import com.atguigu.springboot04.component.LoginHandlerInterceptor;
import com.atguigu.springboot04.component.MyLocaleResolver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/atguigu").setViewName("success");
    }
    //所有的webMvcConfigurerAdapter都会一起起作用
    @Bean
    public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
        WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {



            @Override
            public void addViewControllers(ViewControllerRegistry registry) {
                registry.addViewController("/").setViewName("login");
                registry.addViewController("/index.html").setViewName("login");
                registry.addViewController("/main.html").setViewName("dashboard");
            }

            @Override
            public void addInterceptors(InterceptorRegistry registry) {
                //super.addInterceptors(registry);
                registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
                        .excludePathPatterns("/index.html","/","/user/login","/asserts/**","/webjars/bootstrap/**");
            }
        };

        return  adapter;
    }
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();

    }


}

** 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.atguigu.springboot04.config;

import com.atguigu.springboot04.component.LoginHandlerInterceptor;
import com.atguigu.springboot04.component.MyLocaleResolver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/atguigu").setViewName("success");
    }
    //所有的webMvcConfigurerAdapter都会一起起作用
    @Bean
    public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
        WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {



            @Override
            public void addViewControllers(ViewControllerRegistry registry) {
                registry.addViewController("/").setViewName("login");
                registry.addViewController("/index.html").setViewName("login");
                registry.addViewController("/main.html").setViewName("dashboard");
            }

            @Override
            public void addInterceptors(InterceptorRegistry registry) {
                //super.addInterceptors(registry);
                registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
                        .excludePathPatterns("/index.html","/","/user/login","/asserts/**","/webjars/bootstrap/**");
            }
        };

        return  adapter;
    }
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();

    }


}

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

SpringBoot2.0以上静态资源会被拦截器拦截的原因和解决方法

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