Access to XMLHttpRequest at 'file:///C:/Users/%E6%9D%8E%E5%8D%8E%E6%98%AD/Desktop/material/003-ajax%E5%9F%BA%E7%A1%80/1.json' from origin 'null' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, isolated-app, chrome-extension, chrome, https, chrome-untrusted.

这个错误是由于浏览器的安全策略引起的。浏览器通常会阻止跨域请求（CORS），即从一个源（origin）发出的请求不能访问另一个源的资源。

在这种情况下，你正在尝试从本地文件系统（file://）的源发出请求，而目标资源位于一个不同的源（null）。浏览器默认情况下不允许这样的跨域请求。

要解决这个问题，你可以将资源部署到一个支持跨域请求的服务器上，然后通过HTTP或HTTPS协议访问它。或者，你可以尝试使用一些工具来模拟一个本地服务器，例如使用Python的`SimpleHTTPServer`模块或安装一个本地开发服务器。

如果你只是想在本地测试和查看JSON文件，可以尝试使用一些浏览器插件或者命令行工具来启动一个本地HTTP服务器，并从该服务器上访问文件。

相关问题

Access to XMLHttpRequest at 'file:///E:/projects/ThreejsSpace/fbxTest/Angry.fbx'

Access to XMLHttpRequest at 'file:///E:/projects/ThreejsSpace/fbxTest/Angry.fbx is a security feature implemented in web browsers to prevent cross-origin requests. It means that you are trying to make an XMLHttpRequest to a local file on your computer, which is not allowed due to security restrictions.

To access the file 'Angry.fbx' using XMLHttpRequest, you need to host it on a web server and access it through a valid URL. This can be done by setting up a local web server or uploading the file to a remote server.

Access to XMLHttpRequest at 'file:///D:/vue/vue-first/data.json' from origin 'null' has been blocked by CORS policy

回答: 这个错误是由于浏览器的CORS策略引起的。CORS是一种安全机制，用于限制跨域请求。当浏览器发现请求的源与目标不在同一个域时，会发送一个预检请求，检查目标服务器是否允许跨域请求。如果目标服务器没有正确配置CORS头部，浏览器就会拒绝该请求，从而导致这个错误。\[1\]\[2\]

对于你提到的具体错误，'file:///D:/vue/vue-first/data.json'是一个本地文件路径，而'null'是请求的源。由于这是一个本地文件请求，而不是通过HTTP协议请求，所以CORS策略不适用于这种情况。因此，你可以通过将数据文件放在与你的应用程序相同的域中，或者使用服务器来提供数据，以避免这个错误。
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