ZealousURLEncoder.java

package ca.sqlpower.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class ZealousURLEncoder {

    static final int caseDiff = ('a' - 'A');

    public static String zealousEncode(String s) {
	if(s==null) {
	    return "";
	}

	int maxBytesPerChar = 10;
        StringBuffer out = new StringBuffer(s.length());
        ByteArrayOutputStream buf = new ByteArrayOutputStream(maxBytesPerChar);
        OutputStreamWriter writer = new OutputStreamWriter(buf);

        for (int i = 0; i < s.length(); i++) {
            int c = (int)s.charAt(i);
            if (c == ' ') {
              c = '+';
              out.append((char)c);
            } else {
                // convert to external encoding before hex conversion
                try {
                    writer.write(c);
                    writer.flush();
                } catch(IOException e) {
                    buf.reset();
                    continue;
                }
                byte[] ba = buf.toByteArray();
                for (int j = 0; j < ba.length; j++) {
                    out.append('%');
                    char ch = Character.forDigit((ba[j] >> 4) & 0xF, 16);
                    // converting to use uppercase letter as part of
                    // the hex value if ch is a letter.
                    if (Character.isLetter(ch)) {
                        ch -= caseDiff;
                    }
                    out.append(ch);
                    ch = Character.forDigit(ba[j] & 0xF, 16);
                    if (Character.isLetter(ch)) {
                        ch -= caseDiff;
                    }
                    out.append(ch);
                }
                buf.reset();
            }
        }
        return out.toString();
    }
}