spring boot实现过滤器Filter

spring boot实现过滤器Filter 1 . 创建两个controller

访问helloservlet时判断是否带token，如果不带token会被拦截，跳转到logout

helloservlet 类

@Slf4j
@WebServlet (value = {"/hello"})

public class helloservelt extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        resp.setContentType("text/html;charset=utf-8");
        resp.getWriter().write("hello-servlet");
        log.info("aoligei");
    }
}

logout类

 @RestController
public class logoutservlet {
    @GetMapping("/logout")
    public String logout(){
        return "拦住你了";
    }

    }

2 . 1 注解实现 2 . 1 .1 创建过滤类

//加入过滤器注解，拦截以“/api”开头的地址
@WebFilter("/api/*")
@Slf4j
public class tokenfilter implements Filter {

//重写 doFilter 方法
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //强转为  HttpServlet
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        //获取token
        String token = request.getParameter("token");
        //日志输入token到控制台
        log.info("token:{}", token);
        //判断是否带有token
        if (token == null) {
        //如果不带token 重定向到logout
            response.sendRedirect("/logout");
        }
        //执行拦截
        filterChain.doFilter(request, response);
    }
}

2. 1 . 2 执行结果 2. 1 . 2 . 1 不带token

启动浏览器访问 http://localhost:8080/api/hello
不带token被拦截到了，并且跳转到了 logou 下图是控制台输出

2. 1 . 2 . 2 带token

启动浏览器访问http://localhost:8080/api/hello?token=123456 这里token 随意输入一串字符串即可

2 . 2 注解实现 2 . 2 .1 创建过滤器类

和2.1.1中的过滤器类区别就是少了@WebFilter("/api/*")注解

@Slf4j
public class tokenfilter implements Filter {

//重写 doFilter 方法
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //强转为  HttpServlet
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        //获取token
        String token = request.getParameter("token");
        //日志输入token到控制台
        log.info("token:{}", token);
        //判断是否带有token
        if (token == null) {
        //如果不带token 重定向到logout
            response.sendRedirect("/logout");
        }
        //执行拦截
        filterChain.doFilter(request, response);
    }
}

2 . 2 .2 创建配置类

//spring boot 中配置类需要加这个注解
@Configuration
public class myconfig {
     @Bean
     public FilterRegistrationBean filterRegistrationBean(){

         FilterRegistrationBean filter = new FilterRegistrationBean();
         //把拦截类加进去
         filter.setFilter(new tokenfilter());
         filter.addUrlPatterns("/api/*");
         return filter;
     }
}

执行结果与上相同就不贴了

spring boot实现过滤器Filter

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