SpringBoot2.1.X 自定义Filter

红太狼 2024-04-18 22:29 77阅读 0赞

**自定义Filter**

1）使用Servlet3.0的注解进行配置
    2）启动类里面增加 @ServletComponentScan，进行扫描
    3）新建一个Filter类，implements Filter，并实现对应的接口
    4) @WebFilter 标记一个类为filter，被spring进行扫描 urlPatterns：拦截规则，支持正则
    5）控制chain.doFilter的方法的调用，来实现是否通过放行不放行，web应用 
       resp.sendRedirect("/index.html");
    场景：权限控制、用户登录(非前端后端分离场景)等

1.MyFilter过滤类： （添加@WebFilter注解哦！）

/**
     * 注解
     */
    @WebFilter(urlPatterns = "/your/*",filterName = "LoginFilter")
    public class LoginFilter implements Filter {
    
        /**
         * 容器加载的时候调用
         * @param filterConfig
         * @throws ServletException
         */
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
            System.out.println("LoginFilter init!");
        }
    
        //请求被拦截的时候进行调用
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            System.out.println(" loginFilter  doFilter");
    
            //转换成协议对象
            HttpServletRequest req = (HttpServletRequest) servletRequest;
            HttpServletResponse resp = (HttpServletResponse) servletResponse;
    
            //获得请求数据
            String username = req.getParameter("username");
            //判断相等，则放行
            if ("hlx".equals(username)) {
                filterChain.doFilter(servletRequest,servletResponse);
            } else {
                //不等时，跳转到页面
                resp.sendRedirect("/index.html");
                return;
            }
        }
    
        /**
         * 容器被销毁的时候被调用
         */
        public void destroy() {
            System.out.println("LoginFilter destroy!");
        }
    }

2、Controller类

@RequestMapping(path = "/your/login1")
        public Object login1(){
              maps.put("id",100);
            return maps;
        }

3、在Application 启动类 添加 `@ServletComponentScan` 注解

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hseDIwMDgwODA4_size_16_color_FFFFFF_t_70][]

效果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hseDIwMDgwODA4_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hseDIwMDgwODA4_size_16_color_FFFFFF_t_70 2][]

如果访问[http://localhost:8089/your/login1][http_localhost_8089_your_login1]，那么就会直接跳转到index.html页面哦

![20190912180359529.png][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hseDIwMDgwODA4_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/d88207c44f5645f0a8a582edb1db4196.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hseDIwMDgwODA4_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/e028fa7682494bf7965efeabc8b62d70.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hseDIwMDgwODA4_size_16_color_FFFFFF_t_70 2]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/5dcde02bd3ad4cb686a2589387eb1507.png
[http_localhost_8089_your_login1]: http://localhost:8089/your/login1
[20190912180359529.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/468df2dcc65d42b8a6bd0bbf630b2534.png