簡單總結SpringMVC攔截器的使用方法

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
        // 攔截前的操作
        System.out.println("-----------前置攔截-----------");
        return true;
    }
    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        // 攔截後的操作
        System.out.println("------------後置攔截------------");
    }
 
    @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;
 
/**
 * @擴展springMVC
 * 第一步：
 * @Configuration 註解的作用：讓這個類變為配置類
 * 第二步：
 * 必須實現 WebMvcConfigurer 接口
 */
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
    @Resource
    private MyInterceptor myInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // addInterceptor()：註冊攔截器，參數是一個攔截器
        // addPathPatterns(): 路徑映射，哪些路徑需要被攔截，/** 全部攔截
        // excludePathPatterns(): 排除哪些路徑，不會被攔截
        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;
 
/**
 * 這個是攔截器，與過濾器區別：
 *
 * 【【【【特別註意：增加攔截器，還需要在config中增加一個配置類！配置】】】】
 *
 * （1）攔截器是spring特有的，經常用於登錄校驗、權限驗證、請求打印日志等等。
 * （2）攔截器不需要你手動調用後續代碼執行，它是有兩個方法的，且分開的，一個前，一個後
 * （3）而過濾器，我們會在打印日志的中間，使用filterChain.doFilter()方法去調用後續代碼執行的！
 * （4）攔截器的 preHandle 前置處理方法，必須返回true，否則後續邏輯不會執行，整個業務也會結束！
 */
@Component // 增加這個註解，讓spring能掃描到這個類
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("【全局攔截器】");
        LOG.info("*********** InterceptorLog日志開始 *********** ");
        LOG.info("* 請求地址: {}, 方法: {}", request.getRequestURL().toString(), request.getMethod());
        LOG.info("* 遠程地址: {}, 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 結束，耗時: {} 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");
    }
    
}