解决：vue 用 axios 发送请求，每次都会发送两次请求

怼烎@ 2022-03-22 14:00 1052阅读 0赞

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我的解决方法是后端加一个过滤器：

package gentle.filter;
    
    import javax.servlet.*;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /**
     * 改写所有请求头
     * @author silence
     * @date 2018/12/11 15:19
     */
    
    @WebFilter(filterName = "requestFilter",urlPatterns = {"/*"})
    public class RequestFilter implements Filter {
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    
            HttpServletResponse response = (HttpServletResponse) servletResponse;
            HttpServletRequest request = (HttpServletRequest)servletRequest;
    
            response.setHeader("Access-Control-Allow-Origin", "*");
            response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
            response.setHeader("Access-Control-Max-Age", "3600");
    //        response.setHeader("Access-Control-Allow-Headers", "x-requested-with,Authorization");
            response.setHeader("Access-Control-Allow-Headers", "Content-Type,XFILENAME,XFILECATEGORY,XFILESIZE,x-requested-with,Authorization");
            response.setHeader("Access-Control-Allow-Credentials", "true");
            String method = request.getMethod();
            if(method.equalsIgnoreCase("OPTIONS")){
                servletResponse.getOutputStream().write("Success".getBytes("utf-8"));
            }else{
                filterChain.doFilter(servletRequest, servletResponse);
            }
        }
    
        @Override
        public void destroy() {
    
        }
    
    }

重点是这行代码：

response.setHeader("Access-Control-Allow-Origin", "*");

方法二：前端也加头信息解决。

方法参见：[https://www.cnblogs.com/Tohold/p/9173137.html][https_www.cnblogs.com_Tohold_p_9173137.html]

[Link 1]: https://www.captainai.net/jiangyu1013/
[https_www.cnblogs.com_Tohold_p_9173137.html]: https://www.cnblogs.com/Tohold/p/9173137.html