springboot之过滤器(filter)

springboot之过滤器(filter)

出于要对个别url路径进行限制访问，本来是想借由拦截器实现拦截url路径，但是简单的浏览器地址栏输入localhost:8080/hello.html无法拦截到，于是使用了比拦截器更为广泛的功能的过滤器来实现，权限限制，编码过滤，url重定向

package com.job;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 javax.servlet.annotation.WebFilter;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import com.job.controller.WebSecurityConfig;@WebFilter(filterName="myFilter",urlPatterns="/html/main.html")public class Myfilter implements Filter {    @Override    public void init(FilterConfig arg0) throws ServletException {        System.out.println("MyFilter init");    }    @Override    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)            throws IOException, ServletException {        System.out.println("MyFilter doFilter");        HttpServletRequest req = (HttpServletRequest) request;        HttpServletResponse resp =(HttpServletResponse) response;        HttpSession session = req.getSession();        System.out.println("过滤器执行");        if (session.getAttribute(WebSecurityConfig.SESSION_KEY) != null){            System.out.println("session不为空");             chain.doFilter(request, response);        }else{            resp.sendRedirect("/login");        }        ((HttpServletResponse) response).sendRedirect("/login");        chain.doFilter(request, response);    }    @Override    public void destroy() {        System.out.println("MyFilter destroy");    }}

这里只需在项目里新建一个myfilter类并添加注解，在项目启动时，自动会识别为过滤器，并执行一次初始化init（）方法

public void init(FilterConfig arg0) throws ServletException {        System.out.println("MyFilter init");    }

最后根据@WebFilter(filterName="myFilter",urlPatterns="/html/main.html")类名前写好的注解已经订好的过滤规则进行过滤；

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满足条件则执行dofilter（）方法

public void doFilte（）｛。。。。。。。。。。。此处省略若干字｝

至此，我们的过滤器就开始没日没夜的为我们工作了