java后端通过Filter过滤器解决跨域问题

2019-01-16 05:51:11来源：博客园阅读 ()

此方案只需服务端的代码修改

因为现在要前后端分离开发，那必不可免的会出现跨域问题，以下是自己实际测试过的有效代码：

步骤：

一、在 web.xml文件中添加

<!-- 2019-01-15   解决跨域问题 -->
    <filter>
        <filter-name>crossFilter</filter-name>
        <filter-class>com.sx.test.controller.CorsFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>crossFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

二、在自己的项目中创建 CorsFilter.java文件

package com.sx.test.controller;

import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;

import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebFilter(filterName = "CORSFilter", urlPatterns = {"/*"})
@Order(value = 1)
@Configuration
public class CorsFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)throws IOException, ServletException {
        System.out.println("Filter 过滤器 执行 了");
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        // 响应标头指定 指定可以访问资源的URI路径
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));

        //响应标头指定响应访问所述资源到时允许的一种或多种方法
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE");

        //设置 缓存可以生存的最大秒数
        response.setHeader("Access-Control-Max-Age", "3600");

        //设置  受支持请求标头
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with");

        // 指示的请求的响应是否可以暴露于该页面。当true值返回时它可以被暴露
        response.setHeader("Access-Control-Allow-Credentials","true");

        filterChain.doFilter(servletRequest, servletResponse);

    }

    @Override
    public void destroy() {

    }
}