Spring中过滤器和拦截器的区别及具体实现方式

import javax.servlet.*;
import java.io.IOException;
public class CustomFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) {
        // 初始化逻辑
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
        throws IOException, ServletException {
        // 1. 请求到达 Controller 前的逻辑
        System.out.println("Before Controller (Filter)");
        // 放行请求
        chain.doFilter(request, response);
        // 2. 响应返回客户端前的逻辑
        System.out.println("After Controller (Filter)");
    }
    @Override
    public void destroy() {
        // 销毁逻辑
    }
}

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class FilterConfig {
    @Bean
    public FilterRegistrationBean<CustomFilter> customFilter() {
        FilterRegistrationBean<CustomFilter> bean = new FilterRegistrationBean<>();
        bean.setFilter(new CustomFilter());
        bean.addUrlPatterns("/*"); // 拦截所有路径
        bean.setOrder(1); // 执行顺序
        return bean;
    }
}

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
@Component
public class CustomInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        // 在 Controller 方法执行前调用
        System.out.println("Before Controller (Interceptor)");
        return true; // true=放行, false=中断请求
    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, 
                           ModelAndView modelAndView) {
        // 在 Controller 方法执行后、视图渲染前调用
        System.out.println("After Controller (Interceptor)");
    }
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, 
                                Object handler, Exception ex) {
        // 在整个请求完成后调用（视图渲染完毕）
        System.out.println("After View Render (Interceptor)");
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    @Autowired
    private CustomInterceptor customInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(customInterceptor)
                .addPathPatterns("/**")    // 拦截所有路径
                .excludePathPatterns("/login"); // 排除路径
    }
}

1. Filter: doFilter() [前逻辑]
2. Interceptor: preHandle()
3. Controller 方法执行
4. Interceptor: postHandle()
5. 视图渲染
6. Interceptor: afterCompletion()
7. Filter: doFilter() [后逻辑]