Spring Boot 过滤器、监听器和拦截器使用

1、过滤器和监听器
Spring Boot中对于过滤器和监听器的使用跟一般web工程中使用方式没什么不同,使用注解方式就可以快速创建,只是要使用注解方式需要在Application类加上 @ServletComponentScan 注解表明开启servlet的注解
创建一个监听器

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@WebListener
public class FirstListener implements ServletContextListener{

private static Logger LOG = LoggerFactory.getLogger(FirstListener.class);

@Override
public void contextInitialized(ServletContextEvent sce) {
LOG.info("FirstListener 初始化...");
}

@Override
public void contextDestroyed(ServletContextEvent sce) {
LOG.info("FirstListener 销毁...");
}

}

创建一个过滤器,过滤test和hello下文的所有路径

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@WebFilter(filterName="firstFilter", urlPatterns = {
"/test/*",
"/hello/*"
})
public class FirsrtFilter implements Filter{

private static Logger LOG = LoggerFactory.getLogger(FirsrtFilter.class);

@Override
public void init(FilterConfig filterConfig) throws ServletException {

}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) request;
String requestURI = req.getRequestURI();
LOG.info("过滤到的请求--->"+requestURI);
}

@Override
public void destroy() {

}
}

运行 application 类可看到日志输出
2017-06-08 17:14:55.252 INFO 7552 --- [ost-startStop-1] com.fyft.test.web.FirstListener : FirstListener 初始化...

写一个请求路径为 test 的 controller 并访问,可看到
2017-06-08 17:15:50.799 INFO 7552 --- [nio-8003-exec-1] com.fyft.test.web.FirsrtFilter : 过滤到的请求--->/test

2、拦截器

实现 HandlerInterceptor 接口创建一个拦截器类

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public class MyInterceptor implements HandlerInterceptor {

@Override
public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
throws Exception {
// TODO Auto-generated method stub
//在整个请求结束之后被调用,也就是在DispatcherServlet 渲染了对应的视图之后执行,主要是用于进行资源清理工作
}

@Override
public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
throws Exception {
// TODO Auto-generated method stub
//请求处理之后进行调用,但是在视图被渲染之前,即Controller方法调用之后
}

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object object) throws Exception {
// TODO Auto-generated method stub
//controller方法调用之前
return true;
}

}

然后在初始化配置类中注册拦截器

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@Configuration
public class MyWebAppConfigurer extends WebMvcConfigurerAdapter {

/**
* 添加拦截器
*/
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new MyInterceptor()).addPathPatterns("/*");
//registry.addInterceptor(new MyInterceptor_copy()).addPathPatterns("/*");//有多个拦截器继续add进去
super.addInterceptors(registry);
}

}

这里的拦截器只有经过DispatcherServlet 的请求,才会走拦截器链,默认不拦截静态资源,Spring Boot中默认的静态资源路径有 classpath:/META-INF/resources/,classpath:/resources/,classpath:/static/,classpath:/public/ ,在拦截器中我们可以处理一些我们需要的业务,比如防xss攻击,在调用controller前对提交内容进行过滤等等。

参考博客 http://blog.csdn.net/catoop/article/details/50501696