如何在Java中进行URL解码？

问题描述

| 在Java中，我想将其转换为：

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

对此：

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

这是我到目前为止的内容：

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){
        }
    }
}

但这行不通。这些

%3A

和

%2F

格式叫什么？如何转换它们？     

解决方法

这与字符编码（例如UTF-8或ASCII）无关。您所拥有的字符串经过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在API中添加了对ѭ6的直接支持，这意味着无需捕获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。有关字符编码的良好介绍，请参见本文。     ,您得到的字符串是

application/x-www-form-urlencoded

编码。 使用URLDecoder将其转换为Java String。

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

    ,这已经被回答过（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类进行x-www-form-urlencoded解码是错误的（尽管名称，它用于表单数据）。\” 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

    ,

%3A

和

%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\");

    ,

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

    ,

public String decodeString(String URL)
    {

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

        }

        return urlString;

    }

    ,我使用apache commons

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

默认字符集为

UTF-8

    ,

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\")); 

    } 

}

您可以明智地选择方法：）