JavaScript escape/unescape编码的Java实现

[align=left]符合 JavaScript unescape 函数(支持Unicode)的 Java escape 编码实现[/align]
[align=left]最近在弄一个跨域的交互程序,交互过程非常复杂.而且,其中一端只能使用 javascript 来处理返回.

于是,发现 Java 的 URLEncoder.encode 方法与 JavaScript 的 unescape 方法已经不能兼容了.

现在浏览器的主流版本中 JavaScript 已经开始使用 Unicode 作为字符串的内码进行编码.即, Unicode 字符 escape 之后的样子类似于 %uABCD 而 java 的 URLEncoder.encode 方法得到的结果是 %AB%CD ,转换出来的结果必定是乱码了.

方法有两个,其一,用 Java 实现一个生成新编码的方法.其二,用 JavaScript 实现一个针对旧编码的解码方法.想了想,还是用 Java 要方便一点点吧.

上次贴出的 escape 的 java 实现,似乎对大家有用.最近曾军同学提出 unescape 对于 javascript 与后端的交互也有意义.于是就一并实现了.再次贴上来.

代码非常简单,注释就免了吧.一贯的,仍然遵循"以空间换时间"原则.

需要的桶子,一贯的,help yourself[/align]
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[align=left]public class Escape {
private final static String[] hex = { "00", "01", "02", "03", "04", "05",
"06", "07", "08", "09", "0A", "0B", "0C", "0D", "0E", "0F", "10",
"11", "12", "13", "14", "15", "16", "17", "18", "19", "1A", "1B",
"1C", "1D", "1E", "1F", "20", "21", "22", "23", "24", "25", "26",
"27", "28", "29", "2A", "2B", "2C", "2D", "2E", "2F", "30", "31",
"32", "33", "34", "35", "36", "37", "38", "39", "3A", "3B", "3C",
"3D", "3E", "3F", "40", "41", "42", "43", "44", "45", "46", "47",
"48", "49", "4A", "4B", "4C", "4D", "4E", "4F", "50", "51", "52",
"53", "54", "55", "56", "57", "58", "59", "5A", "5B", "5C", "5D",
"5E", "5F", "60", "61", "62", "63", "64", "65", "66", "67", "68",
"69", "6A", "6B", "6C", "6D", "6E", "6F", "70", "71", "72", "73",
"74", "75", "76", "77", "78", "79", "7A", "7B", "7C", "7D", "7E",
"7F", "80", "81", "82", "83", "84", "85", "86", "87", "88", "89",
"8A", "8B", "8C", "8D", "8E", "8F", "90", "91", "92", "93", "94",
"95", "96", "97", "98", "99", "9A", "9B", "9C", "9D", "9E", "9F",
"A0", "A1", "A2", "A3", "A4", "A5", "A6", "A7", "A8", "A9", "AA",
"AB", "AC", "AD", "AE", "AF", "B0", "B1", "B2", "B3", "B4", "B5",
"B6", "B7", "B8", "B9", "BA", "BB", "BC", "BD", "BE", "BF", "C0",
"C1", "C2", "C3", "C4", "C5", "C6", "C7", "C8", "C9", "CA", "CB",
"CC", "CD", "CE", "CF", "D0", "D1", "D2", "D3", "D4", "D5", "D6",
"D7", "D8", "D9", "DA", "DB", "DC", "DD", "DE", "DF", "E0", "E1",
"E2", "E3", "E4", "E5", "E6", "E7", "E8", "E9", "EA", "EB", "EC",
"ED", "EE", "EF", "F0", "F1", "F2", "F3", "F4", "F5", "F6", "F7",
"F8", "F9", "FA", "FB", "FC", "FD", "FE", "FF" };

private final static byte[] val = { 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F,
0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F, 0x3F };

/**
* 编码
*
* @param s
* @return
*/
public static String escape(String s) {
StringBuffer sbuf = new StringBuffer();
int len = s.length();
for (int i = 0; i < len; i++) {
int ch = s.charAt(i);
if ('A' <= ch && ch <= 'Z') { // 'A'..'Z' : as it was
sbuf.append((char) ch);
} else if ('a' <= ch && ch <= 'z') { // 'a'..'z' : as it was
sbuf.append((char) ch);
} else if ('0' <= ch && ch <= '9') { // '0'..'9' : as it was
sbuf.append((char) ch);
} else if (ch == '-' || ch == '_' // unreserved : as it was
|| ch == '.' || ch == '!' || ch == '~' || ch == '*'
|| ch == '/'' || ch == '(' || ch == ')') {
sbuf.append((char) ch);
} else if (ch <= 0x007F) { // other ASCII : map to %XX
sbuf.append('%');
sbuf.append(hex[ch]);
} else { // unicode : map to %uXXXX
sbuf.append('%');
sbuf.append('u');
sbuf.append(hex[(ch >>> 8)]);
sbuf.append(hex[(0x00FF & ch)]);
}
}
return sbuf.toString();
}

/**
* 解码 说明：本方法保证 不论参数s是否经过escape()编码，均能得到正确的“解码”结果
*
* @param s
* @return
*/
public static String unescape(String s) {
StringBuffer sbuf = new StringBuffer();
int i = 0;
int len = s.length();
while (i < len) {
int ch = s.charAt(i);
if ('A' <= ch && ch <= 'Z') { // 'A'..'Z' : as it was
sbuf.append((char) ch);
} else if ('a' <= ch && ch <= 'z') { // 'a'..'z' : as it was
sbuf.append((char) ch);
} else if ('0' <= ch && ch <= '9') { // '0'..'9' : as it was
sbuf.append((char) ch);
} else if (ch == '-' || ch == '_' // unreserved : as it was
|| ch == '.' || ch == '!' || ch == '~' || ch == '*'
|| ch == '/'' || ch == '(' || ch == ')') {
sbuf.append((char) ch);
} else if (ch == '%') {
int cint = 0;
if ('u' != s.charAt(i + 1)) { // %XX : map to ascii(XX)
cint = (cint << 4) | val[s.charAt(i + 1)];
cint = (cint << 4) | val[s.charAt(i + 2)];
i += 2;
} else { // %uXXXX : map to unicode(XXXX)
cint = (cint << 4) | val[s.charAt(i + 2)];
cint = (cint << 4) | val[s.charAt(i + 3)];
cint = (cint << 4) | val[s.charAt(i + 4)];
cint = (cint << 4) | val[s.charAt(i + 5)];
i += 5;
}
sbuf.append((char) cint);
} else { // 对应的字符未经过编码
sbuf.append((char) ch);
}
i++;
}
return sbuf.toString();
}

public static void main(String[] args) {
String stest = "中文1234 abcd[]()<+>,.~//";
System.out.println(stest);
System.out.println(escape(stest));
System.out.println(unescape(escape(stest)));
}

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