Spring Boot 自定义Filter

一、Filter功能

它使用户可以改变一个 request和修改一个response. Filter 不是一个servlet,它不能产生一个response,它能够在一个request到达servlet之前预处理request,也可以在离开 servlet时处理response.换种说法,filter其实是一个 “servlet chaining” (servlet 链).

一个Filter包括：
1）、在servlet被调用之前截获;
2）、在servlet被调用之前检查servlet request;
3）、根据需要修改request头和request数据;
4）、根据需要修改response头和response数据;
5）、在servlet被调用之后截获.

二、自定义Filter

方法一：

实现filter方法

public class GlobalFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        String requestURI = request.getRequestURI();
        System.out.println(requestURI);
        filterChain.doFilter(request, servletResponse);
    }

    @Override
    public void destroy() {

    }
}

加载Filter 配置

@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean filterRegistration(){
        // 新建过滤器注册类
        FilterRegistrationBean registration = new FilterRegistrationBean();
        // 添加自定义 过滤器
        registration.setFilter(globalFilter());
        // 设置过滤器的URL模式
        registration.addUrlPatterns("/*");
        //设置过滤器顺序
        registration.setOrder(1);
        return registration;
    }
    @Bean
    public GlobalFilter globalFilter(){
        return new GlobalFilter();
    }
}

方法二（推荐）

自定义MyFilter, 如果请求URI 包含 my ，则进行下一步处理

@WebFilter(filterName = "myFilter", urlPatterns = "/*")
public class MyFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("init...");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        String requestURI = request.getRequestURI();
        if(requestURI.contains("my")){
            System.out.println("成功啦。。。, 请求URI是:" + requestURI);
        }
        filterChain.doFilter(request, servletResponse);
    }

    @Override
    public void destroy() {
        System.out.println("destroy...");
    }
}

在Application 启动类添加 @ServletComponentScan 注解

@ServletComponentScan
@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Spring Boot 自定义Filter

一、Filter功能

二、自定义Filter

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