|
/Users/lyon/j4p/src/utils/URLEncoder.java
|
1 /**
2 * Created by IntelliJ IDEA.
3 * User: dlyon
4 * Date: Dec 15, 2003
5 * Time: 2:31:48 PM
6 * To change this template use Options | File Templates.
7 */
8 package utils;
9
10 public class URLEncoder {
11 /**
12 * Provides a method to encode any string into a URL-safe
13 * form.
14 * Non-ASCII characters are first encoded as sequences of
15 * two or three bytes, using the UTF-8 algorithm, before being
16 * encoded as %HH escapes.
17 */
18
19 private final static String[] hex = {
20 "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07",
21 "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e", "%0f",
22 "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17",
23 "%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f",
24 "%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27",
25 "%28", "%29", "%2a", "%2b", "%2c", "%2d", "%2e", "%2f",
26 "%30", "%31", "%32", "%33", "%34", "%35", "%36", "%37",
27 "%38", "%39", "%3a", "%3b", "%3c", "%3d", "%3e", "%3f",
28 "%40", "%41", "%42", "%43", "%44", "%45", "%46", "%47",
29 "%48", "%49", "%4a", "%4b", "%4c", "%4d", "%4e", "%4f",
30 "%50", "%51", "%52", "%53", "%54", "%55", "%56", "%57",
31 "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f",
32 "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67",
33 "%68", "%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f",
34 "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77",
35 "%78", "%79", "%7a", "%7b", "%7c", "%7d", "%7e", "%7f",
36 "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87",
37 "%88", "%89", "%8a", "%8b", "%8c", "%8d", "%8e", "%8f",
38 "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97",
39 "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e", "%9f",
40 "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7",
41 "%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af",
42 "%b0", "%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7",
43 "%b8", "%b9", "%ba", "%bb", "%bc", "%bd", "%be", "%bf",
44 "%c0", "%c1", "%c2", "%c3", "%c4", "%c5", "%c6", "%c7",
45 "%c8", "%c9", "%ca", "%cb", "%cc", "%cd", "%ce", "%cf",
46 "%d0", "%d1", "%d2", "%d3", "%d4", "%d5", "%d6", "%d7",
47 "%d8", "%d9", "%da", "%db", "%dc", "%dd", "%de", "%df",
48 "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6", "%e7",
49 "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef",
50 "%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7",
51 "%f8", "%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff"
52 };
53
54 /**
55 * Encode a string to the "x-www-form-urlencoded" form, enhanced
56 * with the UTF-8-in-URL proposal. This is what happens:
57 *
58 * <ul>
59 * <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z',
60 * and '0' through '9' remain the same.
61 *
62 * <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same.
63 *
64 * <li><p>The space character ' ' is converted into a plus sign '+'.
65 *
66 * <li><p>All other ASCII characters are converted into the
67 * 3-character string "%xy", where xy is
68 * the two-digit hexadecimal representation of the character
69 * code
70 *
71 * <li><p>All non-ASCII characters are encoded in two steps: first
72 * to a sequence of 2 or 3 bytes, using the UTF-8 algorithm;
73 * secondly each of these bytes is encoded as "%xx".
74 * </ul>
75 *
76 * @param s The string to be encoded
77 * @return The encoded string
78 */
79 public static String encode(String s) {
80 StringBuffer sbuf = new StringBuffer();
81 int len = s.length();
82 for (int i = 0; i < len; i++) {
83 int ch = s.charAt(i);
84 if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
85 sbuf.append((char) ch);
86 } else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
87 sbuf.append((char) ch);
88 } else if ('0' <= ch && ch <= '9') { // '0'..'9'
89 sbuf.append((char) ch);
90 } else if (ch == ' ') { // space
91 sbuf.append('+');
92 } else if (ch == '-' || ch == '_' // unreserved
93 || ch == '.' || ch == '!'
94 || ch == '~' || ch == '*'
95 || ch == '\'' || ch == '('
96 || ch == ')') {
97 sbuf.append((char) ch);
98 } else if (ch <= 0x007f) { // other ASCII
99 sbuf.append(hex[ch]);
100 } else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
101 sbuf.append(hex[0xc0 | (ch >> 6)]);
102 sbuf.append(hex[0x80 | (ch & 0x3F)]);
103 } else { // 0x7FF < ch <= 0xFFFF
104 sbuf.append(hex[0xe0 | (ch >> 12)]);
105 sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);
106 sbuf.append(hex[0x80 | (ch & 0x3F)]);
107 }
108 }
109 return sbuf.toString();
110 }
111
112 }
113