Method encode

java/org/apache/catalina/util/URLEncoder.java:170–212

URL encodes the provided path using the given character set. @param path The path to encode @param charset The character set to use to convert the path to bytes @return The encoded path

(String path, Charset charset)

     * @return The encoded path
     */
    public String encode(String path, Charset charset) {

        int maxBytesPerChar = 10;
        StringBuilder rewrittenPath = new StringBuilder(path.length());
        ByteArrayOutputStream buf = new ByteArrayOutputStream(maxBytesPerChar);
        /*
         * Most calls to this method use UTF-8 where malformed input and unmappable character issues are not expected to
         * happen. The only Tomcat code that currently (January 2026) might call this method with something other than
         * UTF-8 is the rewrite valve. In that case, the rewrite rules should be consistent with the configured URI
         * encoding on the Connector. Given all of this, the IAE is only expected to be thrown as a result of
         * configuration errors.
         */
        OutputStreamWriter writer = new OutputStreamWriter(buf, charset.newEncoder()
                .onMalformedInput(CodingErrorAction.REPORT).onUnmappableCharacter(CodingErrorAction.REPORT));

        for (int i = 0; i < path.length(); i++) {
            int c = path.charAt(i);
            if (safeCharacters.get(c)) {
                rewrittenPath.append((char) c);
            } else if (encodeSpaceAsPlus && c == ' ') {
                rewrittenPath.append('+');
            } else {
                // convert to external encoding before hex conversion
                try {
                    writer.write((char) c);
                    writer.flush();
                } catch (IOException ioe) {
                    throw new IllegalArgumentException(ioe);
                }
                byte[] ba = buf.toByteArray();
                for (byte toEncode : ba) {
                    // Converting each byte in the buffer
                    rewrittenPath.append('%');
                    int low = toEncode & 0x0f;
                    int high = (toEncode & 0xf0) >> 4;
                    rewrittenPath.append(hexadecimal[high]);
                    rewrittenPath.append(hexadecimal[low]);
                }
                buf.reset();
            }
        }
        return rewrittenPath.toString();
    }


    @Override