中文URL 转换

public class URLtoUTF8 {    //转换为%E4%BD%A0形式    public static String toUtf8String(String s) {        StringBuffer sb = new StringBuffer();        for (int i = 0; i < s.length(); i++) {            char c = s.charAt(i);            if (c >= 0 && c <= 255) {                sb.append(c);            } else {                byte[] b;                try {                    b = String.valueOf(c).getBytes("utf-8");                } catch (Exception ex) {                    System.out.println(ex);                    b = new byte[0];                }                for (int j = 0; j < b.length; j++) {                    int k = b[j];                    if (k < 0)                        k += 256;                    sb.append("%" + Integer.toHexString(k).toUpperCase());                }            }        }        return sb.toString();    }    //将%E4%BD%A0转换为汉字     public static String unescape(String s) {        StringBuffer sbuf = new StringBuffer();        int l = s.length();        int ch = -1;        int b, sumb = 0;        for (int i = 0, more = -1; i < l; i++) {            /* Get next byte b from URL segment s */            switch (ch = s.charAt(i)) {            case '%':                ch = s.charAt(++i);                int hb = (Character.isDigit((char) ch) ? ch - '0'                        : 10 + Character.toLowerCase((char) ch) - 'a') & 0xF;                ch = s.charAt(++i);                int lb = (Character.isDigit((char) ch) ? ch - '0'                        : 10 + Character.toLowerCase((char) ch) - 'a') & 0xF;                b = (hb << 4) | lb;                break;            case '+':                b = ' ';                break;            default:                b = ch;            }            /* Decode byte b as UTF-8, sumb collects incomplete chars */            if ((b & 0xc0) == 0x80) { // 10xxxxxx (continuation byte)                   sumb = (sumb << 6) | (b & 0x3f); // Add 6 bits to sumb                   if (--more == 0)                    sbuf.append((char) sumb); // Add char to sbuf               } else if ((b & 0x80) == 0x00) { // 0xxxxxxx (yields 7 bits)                   sbuf.append((char) b); // Store in sbuf               } else if ((b & 0xe0) == 0xc0) { // 110xxxxx (yields 5 bits)                   sumb = b & 0x1f;                more = 1; // Expect 1 more byte               } else if ((b & 0xf0) == 0xe0) { // 1110xxxx (yields 4 bits)                   sumb = b & 0x0f;                more = 2; // Expect 2 more bytes               } else if ((b & 0xf8) == 0xf0) { // 11110xxx (yields 3 bits)                   sumb = b & 0x07;                more = 3; // Expect 3 more bytes               } else if ((b & 0xfc) == 0xf8) { // 111110xx (yields 2 bits)                   sumb = b & 0x03;                more = 4; // Expect 4 more bytes               } else /*if ((b & 0xfe) == 0xfc)*/{ // 1111110x (yields 1 bit)                   sumb = b & 0x01;                more = 5; // Expect 5 more bytes               }            /* We don't test if the UTF-8 encoding is well-formed */        }        return sbuf.toString();    }        public static void main(String[] args){        System.out.println(URLtoUTF8.toUtf8String("你"));        System.out.println(URLtoUTF8.unescape("%E4%BD%A0%20%E5%A5%BD"));            }}