拦截器解决跨域问题

大家平时在项目开发中遇到跨域问题是怎么解决的呢？

我相信有很多小伙伴就会回答：在Controller加上@CrossOrigin就可以啦！

但我们知道，在企业开发中，会有很多个controller，controller数量多也便于维护和查找控制层代码

那有没有一种方式能解决这种繁琐的问题呢？答案是肯定的！

下面介绍如何用JSONP解决跨域问题，哦不是用拦截器解决hh

package com.ruben.controller.interceptor;


import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Component
public class CrossOriginIntercept implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        response.setHeader("Access-Control-Allow-Headers", ((HttpServletRequest) request).getHeader("Access-Control-Request-Headers"));
        //跨域时首先会发送一个option请求,这里我们给option请求直接返回正常状态
        if (request.getMethod().equals(RequestMethod.OPTIONS.name())) {
            response.setStatus(HttpStatus.OK.value());
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

然后如果是springboot项目，需要写个webconfig引入一下

@EnableWebMvc
@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(crossOriginIntercept).addPathPatterns("/**").excludePathPatterns("/static/**");
    }

}

如果是spring项目，需要在springmvc.xml中引入

<!-- 拦截器3  跨域问题 -->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.ruben.controller.interceptor.CrossOriginIntercept"></bean>
        </mvc:interceptor>
    </mvc:interceptors>