Spring Boot实现过滤器

1.过滤器

在SpringBoot中使用过滤器不需要在xml文件中配置filter，只需要添加注解@WebFilter同时实现Filter接口

注意：@WebFilter注解为声明此类为filter，第一个参数为该filter起一个名字，第二个参数为说明要拦截的请求地址。

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; @WebFilter(filterName = "test", urlPatterns = "/*")//可以省略 public class UrlFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { System.out.println("----------------------->过滤器被创建"); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest req = (HttpServletRequest) request; HttpServletResponse res = (HttpServletResponse) response; String requestURI = req.getRequestURI(); System.out.println("--------------------->过滤器：请求地址"+requestURI); if(!requestURI.contains("index")){ //contains判断是否包含 request.getRequestDispatcher("/noindex").forward(request, response); //转发。。。 }else{ chain.doFilter(request, response); } } @Override public void destroy() { System.out.println("----------------------->过滤器被销毁"); } }

2.在启动类上面添加@ServletComponentScan(basePackages = {“com.example.filter”})

@ServletComponentScan(basePackages = {"com.example.filter"}) @SpringBootApplication public class SpringbootfilterApplication { public static void main(String[] args) { SpringApplication.run(SpringbootfilterApplication.class, args); } }

3.测试controller层

@RestController public class ControllerFilter { @RequestMapping("/noindex") public Map<String, String> requestFailed(){ Map<String, String> map = new HashMap<>(); map.put("msg", "请求错误"); map.put("code", "-1"); return map; } @RequestMapping("/index") public Map<String, String> userIndex(){ Map<String, String> map = new HashMap<>(); map.put("1", "2"); map.put("2", "1"); return map; } }

4.测试结果

当地址不是index的时候 跳转到noindex

当地址是index时，跳转到index