如何在Java中进行URL解码？

Question

在Java中，我想转换此：

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

要这样：

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

这是我到目前为止有：

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){ 
     } 
    } 
} 

但它不正确。这些%3A和%2F格式叫什么，我该如何转换它们？

Answer 1

这不会有任何与字符编码，如UTF-8或ASCII。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：

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

。注意，字符编码（如UTF-8或ASCII）是什么决定字符的原始字节的映射。有关字符编码的介绍，请参见this article。

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字符串。

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

Answer 3

%3A和%2F是URL编码字符。使用此java代码将其转换回:和/

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

Answer 4

这已经回答了before（当然，这个问题是第一次！）：

“你应该使用java.net.URI中要做到这一点，因为URLDecoder类做的X WWW的形式，进行了urlencoded解码这是错误的（尽管名称，它是用于表单数据）。“

基本上是：

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 5

import java.io.UnsupportedEncodingException; 
import java.net.URISyntaxException; 

public class URLDecoding { 

    String decoded = ""; 

    public String decodeMethod(String url) throws UnsupportedEncodingException 
    { 
     decoded = java.net.URLDecoder.decode(url, "UTF-8"); 
     return decoded; 
//"You should use java.net.URI to do this, as the URLDecoder class does x-www-form-urlencoded decoding which is wrong (despite the name, it's for form data)." 
    } 

    public String getPathMethod(String url) throws URISyntaxException 
    { 
     decoded = new java.net.URI(url).getPath(); 
     return decoded; 
    } 

    public static void main(String[] args) throws UnsupportedEncodingException, URISyntaxException 
    { 
     System.out.println(" Here is your Decoded url with decode method : "+ new URLDecoding().decodeMethod("https%3A%2F%2Fmywebsite%2Fdocs%2Fenglish%2Fsite%2Fmybook.do%3Frequest_type")); 
     System.out.println("Here is your Decoded url with getPath method : "+ new URLDecoding().getPathMethod("https%3A%2F%2Fmywebsite%2Fdocs%2Fenglish%2Fsite%2Fmybook.do%3Frequest")); 

    } 

} 

您可以明智地选择你的方法:)

Answer 6

我用apache commons

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

的默认字符集为UTF-8

Answer 7

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

Answer 8

public String decodeString(String URL) 
    { 

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

     } 

     return urlString; 

    }