实现拦截器

定义FilterService类，配置拦截器（urlPatterns = "/*"拦截所有请求，urlPatterns = "/getAllUser"拦截单个请求）

package com.example.demo.service;

import jakarta.servlet.*;

import jakarta.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter(urlPatterns = "/getAllUser")
public class FilterService implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("======您已进入过滤器======");

        filterChain.doFilter(servletRequest,servletResponse);
    }
}

在启动类中通过ServletComponentScan注释配置拦截的路径

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan(basePackages = "com.example.demo.service")
public class DemoApplication {

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

}

通过拦截器给服务添加自定义方法

定义类中的成员，定义一个改变成员的方法

自定义方法

每次请求拦截之前调用此方法设置新类，即可完成此类的公用

拦截器