Spring security用户URL权限FilterSecurityInterceptor使用解析

这篇文章主要介绍了Spring security用户URL权限FilterSecurityInterceptor使用解析,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
用户通过浏览器发送URL地址，由FilterSecurityInterceptor判断是否具有相应的访问权限。
对于用户请求的方法权限，例如注解@PreAuthorize("hasRole('ADMIN')")，由MethodSecurityInterceptor判断
两个拦截器都继承了AbstractSecurityInterceptor
代码如下
/*
 * Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.security.web.access.intercept;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
/**
 * Performs security handling of HTTP resources via a filter implementation.
 * 通过筛选器实现对HTTP资源的安全处理。
 * <p>
 * The <code>SecurityMetadataSource</code> required by this security interceptor is of
 * type {@link FilterInvocationSecurityMetadataSource}.
 * <p>
 *安全拦截器所需的SecurityMetadataSource类型是FilterInvocationSecurityMetadataSource
 *
 * Refer to {@link AbstractSecurityInterceptor} for details on the workflow.
 * </p>
 *
 * @author Ben Alex
 * @author Rob Winch
 */
public class FilterSecurityInterceptor extends AbstractSecurityInterceptor implements
  Filter {
 // ~ Static fields/initializers
 // =====================================================================================
 private static final String FILTER_APPLIED = "__spring_security_filterSecurityInterceptor_filterApplied";
 // ~ Instance fields
 // ================================================================================================
 /**
 *securityMetadataSource 中包含了一个HashMap，map中保存了用户请求的Http.Method和相应的URL地址
 *例如在Spring boot中，可能是如下的配置,参考图1
 *securityMetadataSource中的内容，参考图2
 */
 private FilterInvocationSecurityMetadataSource securityMetadataSource;
 private Boolean observeOncePerRequest = true;
 // ~ Methods
 // ========================================================================================================
 /**
  * Not used (we rely on IoC container lifecycle services instead)
  *
  * @param arg0 ignored
  *
  * @throws ServletException never thrown
  */
 public void init(FilterConfig arg0) throws ServletException {
 }
 /**
  * Not used (we rely on IoC container lifecycle services instead)
  */
 public void destroy() {
 }
 /**
  * Method that is actually called by the filter chain. Simply delegates to the
  * {@link #invoke(FilterInvocation)} method.
  *
  * @param request the servlet request
  * @param response the servlet response
  * @param chain the filter chain
  *
  * @throws IOException if the filter chain fails
  * @throws ServletException if the filter chain fails
  *
  *
  *通过责任链式调用，执行doFilter方法
  *FilterInvocation中保存了filter相关的信息，比如request，response，chain
  *通过invoke方法处理具体的url过滤
  */
 public void doFilter(ServletRequest request, ServletResponse response,
    FilterChain chain) throws IOException, ServletException {
  FilterInvocation fi = new FilterInvocation(request, response, chain);
  invoke(fi);
 }
 public FilterInvocationSecurityMetadataSource getSecurityMetadataSource() {
  return this.securityMetadataSource;
 }
 public SecurityMetadataSource obtainSecurityMetadataSource() {
  return this.securityMetadataSource;
 }
 public void setSecurityMetadataSource(FilterInvocationSecurityMetadataSource newSource) {
  this.securityMetadataSource = newSource;
 }
 public Class<?> getSecureObjectClass() {
  return FilterInvocation.class;
 }
 public void invoke(FilterInvocation fi) throws IOException, ServletException {
  //获取当前http请求的地址，比如说“/login”
  if ((fi.getRequest() != null)
      && (fi.getRequest().getAttribute(FILTER_APPLIED) != null)
      && observeOncePerRequest) {
   // filter already applied to this request and user wants us to observe
   // once-per-request handling, so don't re-do security checking
   fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
  } else {
   // first time this request being called, so perform security checking
   if (fi.getRequest() != null) {
    fi.getRequest().setAttribute(FILTER_APPLIED, Boolean.TRUE);
   }
   //这里做主要URL比对，将当前URL与securityMetadataSource(我们自己配置)中的URL过滤条件进行比对
   //首先判断当前URL是permit的还是需要验证的
   //若需要验证，尝试加载保存在SecurityContextHolder.getContext()中的已登录信息
   //调用AbstractSecurityInterceptor中的AccessDecisionManager对象的decide方法
   //如果对于配置中需要登录才可访问的URL，已经查找到登录信息，则执行下一个Filter
   InterceptorStatusToken token = super.beforeInvocation(fi);
   try {
    fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
   }
   finally {
    super.finallyInvocation(token);
   }
   super.afterInvocation(token, null);
  }
 }
 /**
  * Indicates whether once-per-request handling will be observed. By default this is
  * <code>true</code>, meaning the <code>FilterSecurityInterceptor</code> will only
  * execute once-per-request. Sometimes users may wish it to execute more than once per
  * request, such as when JSP forwards are being used and filter security is desired on
  * each included fragment of the HTTP request.
  *
  * @return <code>true</code> (the default) if once-per-request is honoured, otherwise
  * <code>false</code> if <code>FilterSecurityInterceptor</code> will enforce
  * authorizations for each and every fragment of the HTTP request.
  */
 public Boolean isObserveOncePerRequest() {
  return observeOncePerRequest;
 }
 public void setObserveOncePerRequest(Boolean observeOncePerRequest) {
  this.observeOncePerRequest = observeOncePerRequest;
 }
}
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