Spring Boot之拦截器与过滤器（完整版）

package com.test.domain;

import javax.servlet.*;
import java.io.IOException;

public class LogCostFilter implements Filter {

　　//servlet容器初始化时
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
　　　　
    }

　　//servlet容器存在时
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        long start = System.currentTimeMillis();
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("Execute cost="+(System.currentTimeMillis()-start));
    }

　　//servlet容器销毁时
    @Override
    public void destroy() {

    }
}

package com.test.config;

import com.test.domain.LogCostFilter;
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 registration(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new LogCostFilter());//实例化Filter类
        filterRegistrationBean.addUrlPatterns("/*");//设置匹配模式,这里设置为所有，可以按需求设置为"/hello"等等
        filterRegistrationBean.setName("LogCostFilter");//设置过滤器名称
        filterRegistrationBean.setOrder(1);//设置执行顺序
        return filterRegistrationBean;
    }
}

package com.test.interceptor;

import org.springframework.lang.Nullable;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LogcostInterceptor implements HandlerInterceptor {
    long start = System.currentTimeMillis();
    //preHandle是在请求执行前执行的
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        start = System.currentTimeMillis();
        return true;
        //返回true,postHandler和afterCompletion方法才能执行
        // 否则false为拒绝执行，起到拦截器控制作用
    }

    //postHandler是在请求结束之后,视图渲染之前执行的,但只有preHandle方法返回true的时候才会执行
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
        System.out.println("Interception cost="+(System.currentTimeMillis()-start));
    }

    //afterCompletion是视图渲染完成之后才执行,同样需要preHandle返回true，
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
        //该方法通常用于清理资源等工作
    }
}

package com.test.config;

import com.test.interceptor.LogcostInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

@Configuration
public class InterceptorConfig extends WebMvcConfigurationSupport {
    /**
     * 静态资源配置
     */
    /*@Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/img/**")
                .addResourceLocations("classpath:/imgs/");

        super.addResourceHandlers(registry);
    }*/

    /**
     * 默认首页配置
     */
//    @Override
//    public void addViewControllers(ViewControllerRegistry registry) {
//        registry.addViewController("/").setViewName("forward:/index");
//        registry.setOrder(Ordered.HIGHEST_PRECEDENCE);
//        super.addViewControllers(registry);
//    }

    /**
     * interceptor配置
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LogcostInterceptor())
                //添加需要验证登录用户操作权限的请求
                .addPathPatterns("/**")
                //这里add为“/**”,下面的exclude才起作用，且不管controller层是否有匹配客户端请求，拦截器都起作用拦截
//                .addPathPatterns("/hello")
                //如果add为具体的匹配如“/hello”，下面的exclude不起作用,且controller层不匹配客户端请求时拦截器不起作用

                //排除不需要验证登录用户操作权限的请求
                .excludePathPatterns("/wang")
                .excludePathPatterns("/css/**")
                .excludePathPatterns("/js/**")
                .excludePathPatterns("/images/**");
        //这里可以用registry.addInterceptor添加多个拦截器实例，后面加上匹配模式
        super.addInterceptors(registry);//最后将register往这里塞进去就可以了
    }
}