简单总结SpringMVC拦截器的使用方法

package com.lxc.springboot.interceptor;
 
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
 
@Component
public class MyInterceptor implements HandlerInterceptor {
    private static final Logger LOG = LoggerFactory.getLogger(LogInterceptor.class);
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        s
        // 拦截前的操作
        System.out.println("-----------前置拦截-----------");
        return true;
    }
    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        // 拦截后的操作
        System.out.println("------------后置拦截------------");
    }
 
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        // 可以做一些清理工作
    }
}

package com.lxc.springboot.config;
 
 
import com.lxc.springboot.intercetor.MyInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
import javax.annotation.Resource;
 
/**
 * @扩展springMVC
 * 第一步：
 * @Configuration 注解的作用：让这个类变为配置类
 * 第二步：
 * 必须实现 WebMvcConfigurer 接口
 */
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
    @Resource
    private MyInterceptor myInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // addInterceptor()：注册拦截器，参数是一个拦截器
        // addPathPatterns(): 路径映射，哪些路径需要被拦截，/** 全部拦截
        // excludePathPatterns(): 排除哪些路径，不会被拦截
        registry.addInterceptor(myInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns("/login");
    }
}

package com.lxc.springboot.interceptor;
 
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
/**
 * 这个是拦截器，与过滤器区别：
 *
 * 【【【【特别注意：增加拦截器，还需要在config中增加一个配置类！配置】】】】
 *
 * （1）拦截器是spring特有的，经常用于登录校验、权限验证、请求打印日志等等。
 * （2）拦截器不需要你手动调用后续代码执行，它是有两个方法的，且分开的，一个前，一个后
 * （3）而过滤器，我们会在打印日志的中间，使用filterChain.doFilter()方法去调用后续代码执行的！
 * （4）拦截器的 preHandle 前置处理方法，必须返回true，否则后续逻辑不会执行，整个业务也会结束！
 */
@Component // 增加这个注解，让spring能扫描到这个类
public class LogInterceptor implements HandlerInterceptor {
    private static final Logger LOG = LoggerFactory.getLogger(LogInterceptor.class);
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        LOG.info("【全局拦截器】");
        LOG.info("*********** InterceptorLog日志开始 *********** ");
        LOG.info("* 请求地址: {}, 方法: {}", request.getRequestURL().toString(), request.getMethod());
        LOG.info("* 远程地址: {}, 域名: {}, 端口: {}", request.getRemoteAddr(), request.getRemoteHost(), request.getRemotePort());
        long startTime = System.currentTimeMillis();
        request.setAttribute("boot-responseTime", startTime);
        return true;
    }
 
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        // request.getAttribute("boot-responseTime") 返回的是Object
        long startTimed = (long) request.getAttribute("boot-responseTime");
        LOG.info(" *********** InterceptorLog 结束，耗时: {} ms *********** ", System.currentTimeMillis() - startTimed);
    }
}

package com.lxc.springboot.config;
 
import com.lxc.springboot.intercetor.LogInterceptor;
import com.lxc.springboot.intercetor.MyInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
import javax.annotation.Resource;
 
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
    @Resource
    private MyInterceptor myInterceptor;
    @Resource
    private LogInterceptor logInterceptor;
    
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(logInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns("/login");
    }
    
}