URL中运用escape()编码，在java中使用request.getParameter()获取参数为null
在做页面开发时使用了Javascript的escape()函数进行URL编码，结果在JSP或Servlet中用request.getParameter()时取不到参数，只返回一个空值。经过Baidu的搜索终于找到了问题所在及解决的办法。
本来Javascript中的escape()是将中文按ISO-8859-1字符集进行URL编码的，那样通过 request.getParameter()是能直接获取到请求参数的，但后来的Javascript将escape()换成了Unicode字符集编 码，如此一来，在JSP和Servlet中就没法直接拿到请求参数了，具体原因我也不知道。
解决办法：
1、首先对中文字符进行两次escape()编码，如要传参数name，值为“你好”，则url的格式为.name=escape(escape("你好"))，这样一来，在request.getParameter()就能取到编码后的参数了。
2、由于取到的参数是 %25u4F60%25u597D 格式的，没法用常规的URLDecoder.decode()来进行解码，还好，这世上的牛人够多，在网上直接找到了一个工具类，能实现 Javascript中escape()及unescape()式的编解码，源代码如下：
package com.hzfx.webgis.util;
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'){
sbuf.append((char) ch);
} else if ('a' <= ch && ch <= 'z'){
sbuf.append((char) ch);
} else if ('0' <= ch && ch <= '9'){
sbuf.append((char) ch);
} else if (ch == '-' || ch == '_' || ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')'){
sbuf.append((char) ch);
} else if (ch <= 0x007F){
sbuf.append('%');
sbuf.append(hex[ch]);
} else{
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'){
sbuf.append((char) ch);
} else if ('a' <= ch && ch <= 'z'){
sbuf.append((char) ch);
} else if ('0' <= ch && ch <= '9'){
sbuf.append((char) ch);
} else if (ch == '-' || ch == '_'|| ch == '.' || ch == '!' || ch == '~' || ch == '*'|| ch == '\'' || ch == '(' || ch == ')'){
sbuf.append((char) ch);
} else if (ch == '%'){
int cint = 0;
if ('u' != s.charAt(i + 1)){
cint = (cint << 4) | val[s.charAt(i + 1)];
cint = (cint << 4) | val[s.charAt(i + 2)];
i += 2;
} else{
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{
sbuf.append((char) ch);
}
i++;
}
return sbuf.toString();
}
public static void main(String[] args){
String stest = "1234 abcd[]()<+>,.~\\";
System.out.println(stest);
System.out.println(escape(stest));
System.out.println(unescape(escape(stest)));
}
}