SpringBoot 之Filter 常用配置方式

淩亂°似流年 2024-04-19 15:50 76阅读 0赞

SpringBoot 配置Filter过滤器方式一：

### 1、通过 @WebFilter 注解来配置 ###

建立UrlFilter类，此例我们模拟判断用户请求地址是否有误：UrlFilter代码如下

@WebFilter(filterName = "urlFilter", urlPatterns = "/*")
    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 servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
     
            HttpServletRequest req = (HttpServletRequest) servletRequest;
            String requestURI = req.getRequestURI();
            System.out.println("--------------------->过滤器：请求地址"+requestURI);
            if(!requestURI.contains("info")){
                servletRequest.getRequestDispatcher("/failed").forward(servletRequest, servletResponse);
            }else{
                filterChain.doFilter(servletRequest, servletResponse);
            }
        }
     
        @Override
        public void destroy() {
     
            System.out.println("----------------------->过滤器被销毁");
        }
    }

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。该类实现了Filter接口，里面有三个方法，分别为过滤器创建、过滤方法和过滤器销毁。

**main函数类上添加@ServletComponentScan（basePackages = "此处写明Filter地址，格式为包名+类名（如com.digipowert.ucas.filter）"）**

### 2、通过 @Bean 注解来配置 ###

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 servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
     
            HttpServletRequest req = (HttpServletRequest) servletRequest;
            String requestURI = req.getRequestURI();
            System.out.println("--------------------->过滤器：请求地址"+requestURI);
            if(!requestURI.contains("info")){
                servletRequest.getRequestDispatcher("/failed").forward(servletRequest, servletResponse);
            }else{
                filterChain.doFilter(servletRequest, servletResponse);
            }
        }
     
        @Override
        public void destroy() {
     
            System.out.println("----------------------->过滤器被销毁");
        }
    }

### 在 @SpringBootApplication 注解的类中，添加自定义Filter。 ###

package com.digipower;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.builder.SpringApplicationBuilder;
    import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.boot.web.servlet.ServletComponentScan;
    import org.springframework.boot.web.support.SpringBootServletInitializer;
    import org.springframework.context.annotation.Bean;
    
    @SpringBootApplication
    public class Application extends SpringBootServletInitializer {
    
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		 SpringApplication.run(Application.class, args);
    	}
    	
    	@Override
        protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
            // 注意这里要指向原先用main方法执行的Application启动类
            return builder.sources(Application.class);
        }
    	
    	@Bean
    	public FilterRegistrationBean urlFilterRegistration() {
    		FilterRegistrationBean registration = new FilterRegistrationBean(new UrlFilter());
    		registration.addUrlPatterns("/*"); //url 拦截路径
    		registration.setName("urlFilter"); // 拦截器名称
    		registration.setOrder(1);   //启动序号
    		return registration;
    	}
    
    }