如何使用java.net.URLConnection触发和处理HTTP请求

问题：

Use of java.net.URLConnection is asked about pretty often here, and the Oracle tutorial is too concise about it. 在这里常常会问到使用java.net.URLConnection状况，而Oracle教程对此过于简洁。

That tutorial basically only shows how to fire a GET request and read the response. 该教程基本上仅显示如何触发GET请求并读取响应。 It doesn't explain anywhere how to use it to among others perform a POST request, set request headers, read response headers, deal with cookies, submit a HTML form, upload a file, etc. 它没有任何地方说明如何使用它来执行POST请求，设置请求标头，读取响应标头，处理cookie，提交HTML表单，上传文件等。

So, how can I use java.net.URLConnection to fire and handle "advanced" HTTP requests? 所以，如何使用java.net.URLConnection来触发和处理“高级” HTTP请求？

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解决方案：

参考一： https://stackoom.com/question/Bico/如何使用java-net-URLConnection触发和处理HTTP请求
参考二： https://oldbug.net/q/Bico/How-to-use-java-net-URLConnection-to-fire-and-handle-HTTP-requests