react 跨域访问后台，默认是有跨域问题，并且火弧和谷歌浏览器，对跨域问题展示还不一样.

谷歌浏览器如下图：

此处状态是200，然而在Response却没有任何信息，如下图

 

然而火弧浏览器，对该问题的描述，就清淅得多，

火弧浏览器告诉我们，跨域了，关于react跨域的帖子，网上也有相关帖子，搜索到的方法，大约都是如下解决方式：

如果你是通过creat-react-app构建的项目，请在package.json文件中的根目录下，添加"proxy": "http://api.xxxx.com"，如果你的项目，需要调用多个不同ip的接口，请使用如下配置：

"proxy": {        "/api/RoomApi": {          "target": "http://open.douyucdn.cn",          "changeOrigin":true        },        "/api/v1":{          "target":"http://capi.douyucdn.cn",          "changeOrigin":true        }      }

对于antd-pro的项目，需要在package.json的同等目录下添加.roadhogrc文件，具体代码如下:

{      "entry": "src/index.js",      "extraBabelPlugins": [        "transform-runtime",        "transform-decorators-legacy",        "transform-class-properties",        ["import", { "libraryName": "antd", "libraryDirectory": "es", "style": true }]      ],      "env": {        "development": {          "extraBabelPlugins": [            "dva-hmr"          ]        }      },      "externals": {        "g2": "G2",        "g-cloud": "Cloud",        "g2-plugin-slider": "G2.Plugin.slider"      },      "ignoreMomentLocale": true,      "theme": "./src/theme.js",      "proxy": {        "/api": {          "target": "http://api.xxxx.com/",          "changeOrigin": true        }      }    }

配置完成后，再次访问接口，还是出现一样的跨域问题，既然recat的配置，未解决跨域问题，我就把思路转到spring，在spring去处理跨域，在后端程序添加一个拦截器,

package com.gg.interceptor;import java.util.ArrayList;import java.util.List;import java.util.Vector;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;public class ProcessInterceptor implements HandlerInterceptor{    @Override    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler)            throws Exception {        // TODO Auto-generated method stub         // 指定白名单域名   http://localhost:8000,http://localhost:8000        List
     
       whileList  = new Vector
      
       ();         whileList.add("http://127.0.0.1:8000");        whileList.add("http://localhost:8000");        String clientIp = httpServletRequest.getHeader("origin");        boolean status = false;        for(String ip : whileList) {            if(clientIp!=null&&clientIp.equals(ip)) {                status = true;                break;            }        }        /**         * 网上解决方案是httpServletResponse.setHeader("Access-Control-Allow-Origin","*");设置后发现，还是不能处理跨域问题，需要指定某一个ip，如：http://127.0.0.1:8000           * */        httpServletResponse.setHeader("Access-Control-Allow-Origin",status?clientIp:null);          //响应头设置          httpServletResponse.setHeader("Access-Control-Allow-Headers", "Content-Type,Content-Length, Authorization, Accept,X-Requested-With");          //响应类型        httpServletResponse.setHeader("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");          httpServletResponse.setHeader("X-Powered-By","Jetty");          httpServletResponse.setHeader("Access-Control-Allow-Credentials","true");        String method= httpServletRequest.getMethod();          if (method.equals("OPTIONS")){              httpServletResponse.setStatus(200);              return false;          }            System.out.println(method+",status:"+status+",clientIp:"+clientIp);            return true;      }    @Override    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,            ModelAndView modelAndView) throws Exception {        // TODO Auto-generated method stub            }    @Override    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)            throws Exception {        // TODO Auto-generated method stub            }}
      
     

spring-servlet.xml配置如下：

react客户端代码如下：

Model层js代码:*login({ payload }, { call, put }){      let formData = new FormData();      formData.append("loginId",payload.loginId);//账号      formData.append("passWord",payload.passWord);//密码      const response = yield call(requestGuangGao, formData);       yield put({        type: 'changeLoginStatus',        payload: response,      });    },api层js代码:export async function requestGuangGao(formData){  // let formData = new FormData();  // formData.append("loginId",params.loginId);  // formData.append("passWord",params.passWord);  console.log("requestGua   >url  :" );   return request('http://127.0.0.1:8080/guanggao/userController/login.do', {    method: 'POST',     mode: 'cors',     body:formData,  });   }

通过以下设置，react跨域问题就处理好了。