【原创】百分号编码(Percent-encoding), 也称作URL编码(URL encoding)简介
百分号编码(Percent-encoding), 也称作URL编码(URL encoding), 是特定上下文的统一资源定位符 (URL)的编码机制. 实际上也适用于统一资源标志符(URI)的编码。
也用于为"application/x-www-form-urlencoded" MIME准备数据, 因为它用于通过HTTP的请求操作(request)提交HTML表单数据。
【以上内容引用自维基百科】
比如，你在百度上检索【百分号编码】时，在浏览器的地址栏里，虽然能看到汉字
但是把地址栏里的内容复制粘贴出来之后就成了下面这个样子，那些百分号开头的就是URL编码
【http://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_idx=1&tn=baidu&wd=%E7%99%BE%E5%88%86%E5%8F%B7%E7%BC%96%E7%A0%81】
在不import任何额外的包的前提下，仅使用Java语言自身支持的功能，就可以对普通的文字和百分号编码之间做出自由的转换
下面是代码示例：
程序代码：/**
* Provides a method to encode any string into a URL-safe
* form.
* Non-ASCII characters are first encoded as sequences of
* two or three bytes, using the UTF-8 algorithm, before being
* encoded as %HH escapes.
* <p/>
* Created: 17 April 1997
* Author: Bert Bos <bert@* <p/>
* URLUTF8Encoder: http://www.
* <p/>
* Copyright © 1997 World Wide Web Consortium, (Massachusetts
* Institute of Technology, European Research Consortium for
* Informatics and Mathematics, Keio University). All Rights Reserved.
* This work is distributed under the W3C® Software License [1] in the
* hope that it will be useful, but WITHOUT ANY WARRANTY; without even
* the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE.
* <p/>
* [1] http://www.
*/
public class URLUTF8Encoder {
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"
};
/**
* Encode a string to the "x-www-form-urlencoded" form, enhanced
* with the UTF-8-in-URL proposal. This is what happens:
* <p/>
* <ul>
* <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z',
* and '0' through '9' remain the same.
* <p/>
* <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same.
* <p/>
* <li><p>The space character ' ' is converted into a plus sign '+'.
* <p/>
* <li><p>All other ASCII characters are converted into the
* 3-character string "%xy", where xy is
* the two-digit hexadecimal representation of the character
* code
* <p/>
* <li><p>All non-ASCII characters are encoded in two steps: first
* to a sequence of 2 or 3 bytes, using the UTF-8 algorithm;
* secondly each of these bytes is encoded as "%xx".
* </ul>
*
* @param s The string to be encoded
* @return The encoded string
*/
public static String encode(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'
sbuf.append((char) ch);
} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
sbuf.append((char) ch);
} else if ('0' <= ch && ch <= '9') { // '0'..'9'
sbuf.append((char) ch);
} else if (ch == ' ') { // space
sbuf.append('+');
} else if (ch == '-' || ch == '_' // unreserved
|| ch == '.' || ch == '!'
|| ch == '~' || ch == '*'
|| ch == '\'' || ch == '('
|| ch == ')') {
sbuf.append((char) ch);
} else if (ch <= 0x007f) { // other ASCII
sbuf.append(hex[ch]);
} else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
sbuf.append(hex[0xc0 | (ch >> 6)]);
sbuf.append(hex[0x80 | (ch & 0x3F)]);
} else { // 0x7FF < ch <= 0xFFFF
sbuf.append(hex[0xe0 | (ch >> 12)]);
sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);
sbuf.append(hex[0x80 | (ch & 0x3F)]);
}
}
return sbuf.toString();
}
/*
* Created: 17 April 1997
* Author: Bert Bos <bert@*
* unescape: http://www.
*
* Copyright © 1997 World Wide Web Consortium, (Massachusetts
* Institute of Technology, European Research Consortium for
* Informatics and Mathematics, Keio University). All Rights Reserved.
* This work is distributed under the W3C® Software License [1] in the
* hope that it will be useful, but WITHOUT ANY WARRANTY; without even
* the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE.
*
* [1] http://www.
*/
/*private*/
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();
}
/**
* Created by 日知己所无 on 2015/02/28. Start
* 参考[http://zh.百分号编码]
* 参考[http://www.]
*/
public static void main(String[] args) {
printPercentEncodingString("大家好。");
printString("\\345\\244\\247\\345\\256\\266\\345\\245\\275\\343\\200\\202");
System.out.println("[" + unescape("%E7%99%BE%E5%88%86%E5%8F%B7%E7%BC%96%E7%A0%81") + "]:[" + encode("百分号编码").toUpperCase() + "]");
}
public static void printPercentEncodingString(String string) {
if (string == null || string.trim().length() == 0) return;
try {
System.out.print("[" + string + "]:[");
String percentEncodingString = encode(string).toUpperCase();
System.out.print(percentEncodingString + "]:[");
for (String s : percentEncodingString.split("%")) {
if (s != null && s.trim().length() > 0) {
System.out.print("\\" + Integer.toOctalString(Integer.parseInt(s, 16)));
}
}
System.out.println("]");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void printString(String string) {
if (string == null || string.trim().length() == 0) return;
try {
System.out.print("[" + string + "]:[");
StringBuffer percentEncodingStringBuffer = new StringBuffer();
for (String s : string.split("\\\\")) {
if (s != null && s.trim().length() > 0) {
percentEncodingStringBuffer.append("%").append(Integer.toHexString(Integer.valueOf(s, 8)));
}
}
String percentEncodingString = percentEncodingStringBuffer.toString().toUpperCase();
System.out.print(percentEncodingString + "]:[");
System.out.println(unescape(percentEncodingString) + "]");
} catch (Exception e) {
e.printStackTrace();
}
}
/** Created by 日知己所无 on 2015/02/28. End */
}下面是执行结果：
[大家好。]:[%E5%A4%A7%E5%AE%B6%E5%A5%BD%E3%80%82]:[\345\244\247\345\256\266\345\245\275\343\200\202] [\345\244\247\345\256\266\345\245\275\343\200\202]:[%E5%A4%A7%E5%AE%B6%E5%A5%BD%E3%80%82]:[大家好。] [百分号编码]:[%E7%99%BE%E5%88%86%E5%8F%B7%E7%BC%96%E7%A0%81]
如果允许import一些其他的包的话，可以简化一些代码
下面是示例：参考了【http://bbs.】的#2楼回复
程序代码：import import java.util.regex.Pattern;
public class URLDecoderTest {
public static void main(String[] args) {
String str = "\\345\\244\\247\\345\\256\\266\\345\\245\\275\\343\\200\\202";
Pattern pattern = ("\\\\");
String[] strs = pattern.split(str);
StringBuffer sb = new StringBuffer();
for (String s : strs) {
if (s != null && s.trim().length() > 0) {
String st = Integer.toHexString(Integer.valueOf(s, 8));
sb.append("%").append(st);
}
}
try {
System.out.println(URLDecoder.decode(sb.toString(), "utf-8"));
} catch (Exception e) {
e.printStackTrace();
}
}
}
下面是执行结果：
大家好。
