拦截器通常通过动态代理的方式来执行。
拦截器的生命周期由IoC容器管理，可以通过注入等方式来获取其他Bean的实例，使用更方便。
示例代码如下：
package com.rongrong.wiki.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;
/**
* 拦截器：Spring框架特有的，常用于登录校验，权限校验，请求日志打印 /login
*/
@Component
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 {
// 打印请求信息
LOG.info("------------- LogInterceptor 开始 -------------");
LOG.info("请求地址: {} {}", request.getRequestURL().toString(), request.getMethod());
LOG.info("远程地址: {}", request.getRemoteAddr());
long startTime = System.currentTimeMillis();
request.setAttribute("requestStartTime", startTime);
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
long startTime = (Long) request.getAttribute("requestStartTime");
LOG.info("------------- LogInterceptor 结束 耗时：{} ms -------------", System.currentTimeMillis() - startTime);
}
}
将拦截器加入到配置中，示例代码如下：
package com.rongrong.wiki.config;
import com.rongrong.wiki.interceptor.LogInterceptor;
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
LogInterceptor loginInterceptor;
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(loginInterceptor)
.addPathPatterns("/**")
.excludePathPatterns("/login");
}
}
重新编译启动，查看结果如下：
true会往后执行false会结束，可以利用这点来做权限拦截addPathPatterns() ，要拦截请求excludePathPatterns() ，排除请求，不拦截servlet容器，拦截器依赖Spring框架
