如何在Java中进行URL解码？

Question

在Java中,我想转换它:

https%3A%2F%2Fmywebsite%2Fdocs%2Fenglish%2Fsite%2Fmybook.do%3Frequest_type

对此:

https://mywebsite/docs/english/site/mybook.do&request_type

这是我到目前为止:

class StringUTF 
{
    public static void main(String[] args) 
    {
        try{
            String url = 
               "https%3A%2F%2Fmywebsite%2Fdocs%2Fenglish%2Fsite%2Fmybook.do" +
               "%3Frequest_type%3D%26type%3Dprivate";

            System.out.println(url+"Hello World!------->" +
                new String(url.getBytes("UTF-8"),"ASCII"));
        }
        catch(Exception E){
        }
    }
}

但它不能正常工作.这些%3A和%2F格式被称为什么以及如何转换它们？

Answer 1

这与UTF-8或ASCII等字符编码无关.你在那里的字符串是URL编码.这种编码与字符编码完全不同.

尝试这样的事情:

try {
    String result = java.net.URLDecoder.decode(url, StandardCharsets.UTF_8.name());
} catch (UnsupportedEncodingException e) {
    // not going to happen - value came from JDK's own StandardCharsets
}

Java 10增加Charset了对API的直接支持,这意味着不需要捕获UnsupportedEncodingException:

String result = java.net.URLDecoder.decode(url, StandardCharsets.UTF_8);

请注意,字符编码(例如UTF-8或ASCII)决定了字符到原始字节的映射.有关字符编码的详细介绍,请参阅此文章.

Answer 2

你得到的字符串是application/x-www-form-urlencoded编码.

使用URLDecoder将其转换为Java String.

URLDecoder.decode( url, "UTF-8" );

Answer 3

之前已经回答过(尽管这个问题是第一个!):

"您应该使用java.net.URI来执行此操作,因为URLDecoder类执行x-www-form-urlencoded解码是错误的(尽管名称,它是表单数据)."

基本上:

String url = "https%3A%2F%2Fmywebsite%2Fdocs%2Fenglish%2Fsite%2Fmybook.do%3Frequest_type";
System.out.println(new java.net.URI(url).getPath());

会给你:

https://mywebsite/docs/english/site/mybook.do?request_type

Answer 4

%3A并且%2F是URL编码的字符.使用此java代码将它们转换回:和/

String decoded = java.net.URLDecoder.decode(url, "UTF-8");

Answer 5

我使用阿帕奇公共资源

String decodedUrl = new URLCodec().decode(url);

默认字符集是UTF-8

Answer 6

 try {
        String result = URLDecoder.decode(urlString, "UTF-8");
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

Answer 7

public String decodeString(String URL)
    {

    String urlString="";
    try {
        urlString = URLDecoder.decode(URL,"UTF-8");
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block

        }

        return urlString;

    }