java url no protocol,java.net.MalformedURLException：基于使用URLEncoder修改的字符串，URL上没有协议...

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博客内容涉及在使用URL时遇到的字符编码问题。作者尝试将字符串用于URL，但遇到了非法字符错误。通过搜索了解到问题源于URL中的特殊字符，如'&'。作者尝试使用URLEncoder.encode()进行编码，但导致了MalformedURLException。解决方案是先创建URL对象，然后对参数值进行编码。关键词包括URL编码、特殊字符、URISyntaxException和HttpGet。

So I was attempting to use this String in a URL :-

http://site-test.collercapital.com/Meetings/IC/DownloadDocument?meetingId=c21c905c-8359-4bd6-b864-844709e05754&itemId=a4b724d1-282e-4b36-9d16-d619a807ba67&file=\\s604132shvw140\Test-Documents\c21c905c-8359-4bd6-b864-844709e05754_attachments\7e89c3cb-ce53-4a04-a9ee-1a584e157987\myDoc.pdf

In this code: -

String fileToDownloadLocation = //The above string

URL fileToDownload = new URL(fileToDownloadLocation);

HttpGet httpget = new HttpGet(fileToDownload.toURI());

But at this point I get the error: -

java.net.URISyntaxException: Illegal character in query at index 169:Blahblahblah

I realised with a bit of googling this was due to the characters in the URL (guessing the &), so I then added in some code so it now looks like so: -

String fileToDownloadLocation = //The above string

fileToDownloadLocation = URLEncoder.encode(fileToDownloadLocation, "UTF-8");

URL fileToDownload = new URL(fileToDownloadLocation);

HttpGet httpget = new HttpGet(fileToDownload.toURI());

However, when I try and run this I get an error when I try and create the URL, the error then reads: -

java.net.MalformedURLException: no protocol: http%3A%2F%2Fsite-test.collercapital.com%2FMeetings%2FIC%2FDownloadDocument%3FmeetingId%3Dc21c905c-8359-4bd6-b864-844709e05754%26itemId%3Da4b724d1-282e-4b36-9d16-d619a807ba67%26file%3D%5C%5Cs604132shvw140%5CTest-Documents%5Cc21c905c-8359-4bd6-b864-844709e05754_attachments%5C7e89c3cb-ce53-4a04-a9ee-1a584e157987%myDoc.pdf

It looks like I can't do the encoding until after I've created the URL else it replaces slashes and things which it shouldn't, but I can't see how I can create the URL with the string and then format it so its suitable for use. I'm not particularly familiar with all this and was hoping someone might be able to point out to me what I'm missing to get string A into a suitably formatted URL to then use with the correct characters replaced?

Any suggestions greatly appreciated!

解决方案

You need to encode your parameter's values before concatenating them to URL.

Backslash \ is special character which have to be escaped as %5C

Escaping example:

String paramValue = "param\\with\\backslash";

String yourURLStr = "http://host.com?param=" + java.net.URLEncoder.encode(paramValue, "UTF-8");

java.net.URL url = new java.net.URL(yourURLStr);

The result is http://host.com?param=param%5Cwith%5Cbackslash which is properly formatted url string.