SpringBoot实现拦截器的完整指南

<!-- pom.xml -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 自定义登录拦截器
 */
public class LoginInterceptor implements HandlerInterceptor {

    private static final Logger log = LoggerFactory.getLogger(LoginInterceptor.class);

    // 控制器执行前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("【拦截器】请求进入 preHandle，地址：{}", request.getRequestURI());

        // 示例：登录校验（从session获取登录用户）
        Object user = request.getSession().getAttribute("loginUser");
        if (user == null) {
            log.info("【拦截器】未登录，拦截请求");
            // 重定向到登录页 / 前后端分离则返回JSON
            response.sendRedirect("/login");
            return false; // 拦截请求
        }
        return true; // 放行
    }

    // 控制器执行后，视图渲染前
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("【拦截器】执行 postHandle");
    }

    // 整个请求完成后（最后执行）
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("【拦截器】请求结束 afterCompletion");
    }
}

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * Web 全局配置类，注册拦截器
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor())
                // 1. 拦截所有请求
                .addPathPatterns("/**")
                // 2. 放行路径：登录接口、静态资源、首页等
                .excludePathPatterns("/login")
                .excludePathPatterns("/static/**")
                .excludePathPatterns("/error"); // 放行全局异常页
    }
}

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpSession;

@RestController
public class TestController {

    // 登录接口（放行）
    @GetMapping("/login")
    public String login(HttpSession session) {
        // 模拟登录成功，存入session
        session.setAttribute("loginUser", "admin");
        return "登录成功";
    }

    // 需拦截的接口
    @GetMapping("/index")
    public String index() {
        return "首页内容";
    }
}

@Override
public void addInterceptors(InterceptorRegistry registry) {
    // 拦截器1 先执行
    registry.addInterceptor(new Interceptor1()).addPathPatterns("/**");
    // 拦截器2 后执行
    registry.addInterceptor(new Interceptor2()).addPathPatterns("/**");
}

if (user == null) {
    response.setContentType("application/json;charset=utf-8");
    response.getWriter().write("{\"code\":401,\"msg\":\"请先登录\"}");
    return false;
}

.excludePathPatterns("/static/**", "/public/**")

.addPathPatterns("/api/user/**")

// SpringBoot3 导入包
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;