转自：http://blog.csdn.net/sunhuwh/article/details/41809909
URL中的字符只能是ASCII字符，但是ASCII字符比较少，而URL则常常包含ASCII字符集以外的字符，如非英语字符、汉字、特殊符号等等，所以要对URL进行转换。这个过程就叫做URL编码，或者叫URL转义，实质上就是将包含非ASCII字符的URL转换为有效的ASCII字符格式。
在进行URL编码时，每一个非ASCII字符都被替换为“%hh”格式，其中hh为两位十六进制数，它对应于该字符在ISO-8859-1字符集里的编码值。比如“中国”这两个汉字出现在URL，就要将他们转为“%D6%D0%B9%FA”，由于一个汉字需要两个字节，所以“中国”被替换成了四个ASCII字符。
public static void main(String[] args) throws UnsupportedEncodingException{ ???????String s = "zhaoxiaofnag%40eims.com.cn "; ???????s=URLDecoder.decode(s,"utf-8"); ???????System.out.println(s); ???????????????String china = "%31%32%36%2E%61%6D/hEeGv4"; ???????china = URLDecoder.decode(china,"utf-8"); ???????System.out.println(china); ???}另附上ASCII字符与URL编码的对照表。ASCII字符 ??URL编码空格 ????%20! ????%21" ???%22# ??%23$ ???%24% ??%25& ???%26‘ ????%27( ???%28) ???%29* ???%2A+ ??%2B, ????%2C- ????%2D. ????%2E/ ???%2F0 ???%301 ???%312 ???%323 ???%334 ???%345 ???%356 ???%367 ???%378 ???%389 ???%39: ????%3A; ????%3B< ??%3C = ??%3D > ??%3E? ???%3F@ ??%40A ???%41B ???%42C ???%43D ???%44E ???%45F ???%46G ???%47H ???%48I ???%49J ???%4AK ???%4BL ???%4CM ??%4DN ???%4EO ??%4FP ???%50Q ??%51R ???%52S ???%53T ???%54U ???%55V ???%56W ??%57X ???%58Y ???%59Z ???%5A[ ???%5B\ ???%5C] ???%5D^ ??%5E_ ???%5F` ???%60a ???%61b ???%62c ???%63d ???%64e ???%65f ????%66g ???%67h ???%68i ????%69j ????%6Ak ???%6Bl ????%6Cm ??%6Dn ???%6Eo ???%6Fp ???%70q ???%71r ????%72s ???%73t ????%74u ???%75v ???%76w ??%77x ???%78y ???%79z ???%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? ??%A9a ???%AA? ???%AB? ??%ACˉ ???%AD? ??%AEˉ ???%AF° ???%B0± ??%B12 ???%B23 ???%B3′ ????%B4μ ???%B5? ???%B6· ????%B7? ????%B81 ???%B9o ???%BA? ???%BB? ??%BC? ??%BD? ??%BE? ???%BFà ???%C0á ???%C1? ???%C2? ???%C3? ???%C4? ???%C5? ??%C6? ???%C7è ???%C8é ???%C9ê ???%CA? ???%CBì ???%CCí ???%CD? ???%CE? ???%CFD ??%D0? ???%D1ò ??%D2ó ??%D3? ??%D4? ??%D5? ??%D6%D7? ??%D8ù ???%D9ú ???%DA? ???%DBü ???%DCY ???%DDT ???%DE? ???%DFà ???%E0á ???%E1a ???%E2? ???%E3? ???%E4? ???%E5? ??%E6? ???%E7è ???%E8é ???%E9ê ???%EA? ???%EBì ????%ECí ????%ED? ????%EE? ????%EFe ???%F0? ???%F1ò ???%F2ó ???%F3? ???%F4? ???%F5? ???%F6÷ ??%F7? ???%F8ù ???%F9ú ???%FA? ???%FBü ???%FCy ???%FDt ???%FE? ???%FFURL转义
原文地址：https://www.cnblogs.com/herizai/p/8467357.html