localhost上的Angular2 CORS问题 [英] Angular2 CORS issue on localhost

问题描述

Failed to load URL: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4200' is therefore not allowed access.

是否可以在不更改服务器端代码（Java Spring Controller）的情况下从Angular2修复此问题？

Is it possible to fix this from Angular2 without changing the code in server side (Java Spring Controller)?

我的代码

const headers = new Headers({'Content-Type': 'application/json',
    'Access-Control-Allow-Origin' : '*'
});
return this.http.get(url, {headers: headers})
  .toPromise()
  .then(response => response.json().data as Hero[])
  .catch(this.handleError);

推荐答案

您的后端似乎不接受跨域请求。

Your backend seems not to accept cross domain requests.

为了让它在Angular上工作，你必须使用一个代理，这样你的前端和你的后端使用相同的域（相同的主机名和相同的端口）

In order to get it to work on Angular, you have to use a proxy so that your frontend and your backend use the same domain (same host name and same port)

在开发模式下，您可以使用 proxy.config.json 文件设置代理。假设您的后端托管在 your-domain.com:80 上，并且您的后端请求以 / backend 开头，此文件包含类似

In development mode, you can set up a proxy using a proxy.config.json file. Supposing that your backend is hosted on your-domain.com:80, and your backend requests start with /backend, this file would contain something like

{
    "/backend/*":{
        "target": "your-domain.com",
        "secure": false,
        "logLevel": "debug"
    }
}

通过更改package.json中的以下配置，使您的开发HTTP服务器使用此文件

Make your development HTTP server use this file by changing the following configuration in your package.json

 "scripts": {
    "start": "ng serve --proxy-config proxy.config.json",
  }

不要忘记使用 http：// localhost：4200 / backend /等请求来调用你的后端... 而不是 http：//your-domain.com / ...

为了使其在远程服务器上运行，您必须在Java Web应用程序（例如nginx或Apache）上设置一个HTTP服务器，该服务器配置为执行与之前相同的操作。

In order to get it to work on a remote server, you must set up an HTTP server over your Java web application (for example nginx or Apache) configured to do the same as explained before.

这篇关于localhost上的Angular2 CORS问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！