Springboot解决跨域GET请求成功POST失败解决方案

灰太狼 2023-10-07 22:09 11阅读 0赞

最近在部署前后端分离项目，遇到跨域问题，处理了半天。发现GET请求通了，但是PUT、POST等请求方法不通。

## 现场 ##

前端部署在本地9090端口：`http://127.0.0.1:9090`  
后端部署在本地9999端口：`http://127.0.0.1:9999`

前端使用 axios 客户端工具，后端使用 springboot 2.4.6

浏览器控制台报错：

`Access to XMLHttpRequest at 'http://127.0.0.1:9999/jtest/post' from origin 'http://127.0.0.1:9090' has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.`

## 分析 ##

意思是说：  
前端调用后端 ‘http://127.0.0.1:9999/jtest/post’ 接口时发生跨域，并且跨域校验未通过，原因是前端的请求头信息`content-type`不被允许，因为在 respose 的头信息 `Access-Control-Allow-Headers` 中未配置。

**注意错误重点是：**  
**Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.**

因此在response的头信息中加上 `content-type` 即可

response.setHeader("Access-Control-Allow-Headers", "content-type");

## 总结 ##

经过简单测试，如果对请求地址，请求头信息等不做要求，使用以下代码可以解决大多数跨域问题。

import java.io.IOException;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletResponse;
    
    import org.springframework.stereotype.Component;
    
    @Component  
    public class CorsFilter implements Filter {
          
        @Override
        public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
          
            // HttpServletRequest request = (HttpServletRequest) req;
            HttpServletResponse response = (HttpServletResponse) res;  
            response.setHeader("Access-Control-Allow-Origin", "*");  
            response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT, GET");  
            response.setHeader("Access-Control-Max-Age", "3600");  
            response.setHeader("Access-Control-Allow-Headers", "**");  
            chain.doFilter(req, res);  
        }  
        @Override
        public void init(FilterConfig filterConfig) {
        }  
    
        @Override
        public void destroy() {
        }  
    }