Spring过滤器和拦截器的区别
两者的作用
过滤器：
在javaweb上，您传递的request、response会预先过滤一些信息，预先设置一些参数，然后传递给servlet或struts操作进行业务逻辑。 例如，过滤不正确的URL (不是log in.do的地址请求，或者如果用户没有登录就进行过滤。
拦截器 ：
面向切面编程是拦截器的一个简单实现，在服务或方法之前调用方法，在方法之后调用方法，在调用方法之前打印字符串(或操作了其他业务逻辑)
从具体实现区分
1 .过滤器是servlet的
2 .拦截器是spring aop的
细节区别
拦截器基于Java的反射机制，滤波器基于函数回调。
拦截器不依赖于servlet容器，过滤器依赖于servlet容器。
拦截器只对action请求起作用，但过滤器几乎对所有请求起作用。
阻止程序可以访问action上下文、值堆栈中的对象，但不能访问过滤器。
在action的生命周期中，将多次调用阻止程序，但在容器初始化时只调用一次过滤器。
拦截器可以获取IOC容器中的各个bean，但不能进行过滤，这一点很重要。 向拦截器注入服务后，可以调用业务逻辑。
工作流程及顺序
应用场景
对于不使用bean的请求预处理和响应后处理，可以进行编码、酷睿等过滤
如果使用bean，或者逻辑复杂且需要特殊处理，请使用拦截器
3 .但是，也可以不怕麻烦，自己建APP
代码实现
拦截器：
继承spring的HandlerInterceptorAdapter
Java代码publicclassessioninterceptorextendshandl
erInterceptorAdapter { private static ThreadLocal<UserSessionVO> threadLocal = new ThreadLocal<UserSessionVO>(); private final Logger logger = LoggerFactory.getLogger(this.getClass()); @Autowired private UserSessionService userSessionService; @PostConstruct public void init() { logger.info("init"); } @PreDestroy public void destroy() { logger.info("destroy"); } @Override public boolean preHandle(final HttpServletRequest request, final HttpServletResponse response, final Object handler) throws Exception { logger.debug("SessionInterceptor.preHandle run...."); final URLAnalysis urlAnalysis = (URLAnalysis) request.getAttribute(Constants.URL_ANALYSIS); final String userIdString = urlAnalysis.getParam(Constants.USERID); final String accessToken = urlAnalysis.getParam(Constants.ACCESSTOKEN); if (!StringUtils.isNotEmpty(userIdString)) { throw new InvalidArgumentException("userId is required"); } if (!StringUtils.isNotEmpty(accessToken)) { throw new InvalidArgumentException("accessToken is required"); } if (!NumberUtils.isNumber(userIdString)) { throw new InvalidArgumentException("userId[" + userIdString + "] invalid"); } final boolean result = userSessionService.checkLogin(Long.valueOf(userIdString), accessToken); if (!result) { throw new InvalidUserSessionException("Invalid accessToken[" + accessToken + "]"); } final UserSessionVO userSessionVO = new UserSessionVO(); userSessionVO.setUserId(Long.valueOf(userIdString)); userSessionVO.setAccessToken(accessToken); threadLocal.set(userSessionVO); return result; } @Override public void afterCompletion(final HttpServletRequest request, final HttpServletResponse response, final Object handler, final Exception ex) throws Exception { logger.debug("SessionInterceptor.afterCompletion run...."); final UserSessionVO userSessionVO = threadLocal.get(); if (userSessionVO != null) { // renewal session userSessionService.renewalSessoin(userSessionVO.getUserId(), userSessionVO.getAccessToken()); } threadLocal.remove(); } }
过滤器：
继承java的Filter，其实现是servlet
Java代码 public class CorsFilter implements Filter { // private final Log logger = LogFactory.getLog(this.getClass()); private final String allowedOrigins; private final String allowCredentials; public CorsFilter(final String allowedOrigins, final String allowCredentials) { this.allowedOrigins = allowedOrigins; this.allowCredentials = allowCredentials; } @Override public void init(final FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(final ServletRequest req, final ServletResponse res, final FilterChain chain) throws IOException, ServletException { final HttpServletRequest request = (HttpServletRequest) req; final HttpServletResponse response = (HttpServletResponse) res; final String method = request.getMethod(); // this origin value could just as easily have come from a database response.setHeader("Access-Control-Allow-Origin", allowedOrigins); response.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, DELETE, OPTIONS"); response.setHeader("Access-Control-Max-Age", "3600"); response.setHeader("Access-Control-Allow-Credentials", allowCredentials); // "Content-Type, X-Requested-With, accept, Origin, Access-Control-Request-Method, Access-Control-Request-Headers" response.setHeader("Access-Control-Allow-Headers", "Origin,Accept,X-Requested-With,Content-Type,Access-Control-Request-Method,Access-Control-Request-Headers,Authorization," + Constants.SESSIONID + "," + Constants.CSRFTOKEN); if ("OPTIONS".equals(method)) { response.setStatus(HttpStatus.OK.value()); } else { chain.doFilter(req, res); } } @Override public void destroy() { } }