如何使用Java实现类似JavaScript decodeURIComponent(escape(x))的功能，恢复错误编码后的乱码字符串？

Let's break down what the JavaScript decodeURIComponent(escape(x)) does first, then map that logic to Java for a clean solution:

Understanding the JavaScript Logic #

• escape(x) takes the garbled string x (which comes from UTF-8 bytes incorrectly decoded as ISO-8859-1) and converts each character to its corresponding byte value in %XX format. Since ISO-8859-1 is a single-byte encoding, every character maps directly to one byte—exactly matching how escape handles non-ASCII characters here.
• decodeURIComponent() then parses those %XX sequences back into UTF-8 bytes, and decodes them correctly into the original Unicode string.

Java Implementation Steps #

To replicate this behavior in Java, follow these straightforward steps:

1. Encode the garbled string to a byte array using ISO-8859-1—this reverses the incorrect decoding step, retrieving the original UTF-8 bytes.
2. Convert each byte in the array to its URI-encoded %XX string representation (matching what escape() outputs).
3. Decode this URI-encoded string using UTF-8 to get the original, correct string.

Full Code Example #

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;

public class GarbledStringRecovery {
    public static void main(String[] args) throws UnsupportedEncodingException {
        // The garbled string from your question
        String garbledText = "ÐÑибка валидаÑии аÑÑибÑÑов докÑменÑа";
        
        // Step 1: Get ISO-8859-1 bytes from the garbled string
        byte[] isoBytes = garbledText.getBytes("ISO-8859-1");
        
        // Step 2: Convert bytes to URI-encoded string (matches escape() behavior)
        String uriEncoded = URLEncoder.encode(new String(isoBytes, "ISO-8859-1"), "UTF-8");
        
        // Step 3: Decode URI string to recover original UTF-8 string
        String originalString = URLDecoder.decode(uriEncoded, "UTF-8");
        
        // Output the result
        System.out.println("Recovered original string: " + originalString);
        // Expected output: Ошибка валидации атрибутов документа
    }
}

Explanation #

• ISO-8859-1 Encoding: This is critical because it preserves the exact byte values of the garbled characters. Since the garbled text was created by misinterpreting UTF-8 bytes as ISO-8859-1, reversing this step gives us back the original UTF-8 byte sequence.
• URI Encoding/Decoding: URLEncoder.encode() converts the ISO-8859-1 string to %XX format, just like escape(). URLDecoder.decode() then reads those %XX sequences as UTF-8 bytes and decodes them into the correct Unicode string.

Shortened One-Liner #

For a more concise version (while keeping the same logic), you can combine all steps into a single line:

String original = URLDecoder.decode(URLEncoder.encode(garbledText, "ISO-8859-1"), "UTF-8");

This one-liner behaves exactly like decodeURIComponent(escape(x)) in JavaScript.

内容的提问来源于stack exchange，提问作者Eugene