?? urlencoder.java
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package com.j2medev.httpme.tools;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.OutputStreamWriter;import java.io.UnsupportedEncodingException;/** * Utility class for form encoding.this class is modified form java.net.URLEncoder so that it can work well in cldc env. * This class contains static methods * for converting a String to the <CODE>application/x-www-form-urlencoded</CODE> MIME * format. For more information about HTML form encoding, consult the HTML * <A HREF="http://www.w3.org/TR/html4/">specification</A>. * * <p> * When encoding a String, the following rules apply: * * <p> * <ul> * <li>The alphanumeric characters "<code>a</code>" through * "<code>z</code>", "<code>A</code>" through * "<code>Z</code>" and "<code>0</code>" * through "<code>9</code>" remain the same. * <li>The special characters "<code>.</code>", * "<code>-</code>", "<code>*</code>", and * "<code>_</code>" remain the same. * <li>The space character "<code> </code>" is * converted into a plus sign "<code>+</code>". * <li>All other characters are unsafe and are first converted into * one or more bytes using some encoding scheme. Then each byte is * represented by the 3-character string * "<code>%<i>xy</i></code>", where <i>xy</i> is the * two-digit hexadecimal representation of the byte. * The recommended encoding scheme to use is UTF-8. However, * for compatibility reasons, if an encoding is not specified, * then the default encoding of the platform is used. * </ul> * * <p> * For example using UTF-8 as the encoding scheme the string "The * string ü@foo-bar" would get converted to * "The+string+%C3%BC%40foo-bar" because in UTF-8 the character * ü is encoded as two bytes C3 (hex) and BC (hex), and the * character @ is encoded as one byte 40 (hex). * * @author mingjava * @version 0.1 05/06/2006 * @since httpme 0.1 */public class URLEncoder { /** The characters which do not need to be encoded. */ private static boolean[] dontNeedEncoding; private static String defaultEncName = ""; static final int caseDiff = ('a' - 'A'); static { dontNeedEncoding = new boolean[256]; int i; for (i = 'a'; i <= 'z'; i++) { dontNeedEncoding[i] = true; } for (i = 'A'; i <= 'Z'; i++) { dontNeedEncoding[i] = true; } for (i = '0'; i <= '9'; i++) { dontNeedEncoding[i] = true; } dontNeedEncoding[' '] = true; // encoding a space to a + is done in the encode() method dontNeedEncoding['-'] = true; dontNeedEncoding['_'] = true; dontNeedEncoding['.'] = true; dontNeedEncoding['*'] = true; defaultEncName = System.getProperty("microedition.encoding"); if(defaultEncName == null || defaultEncName.trim().length() == 0){ defaultEncName = "UTF-8"; } } public static final int MIN_RADIX = 2; /** * The maximum radix available for conversion to and from strings. */ public static final int MAX_RADIX = 36; /** * The class is not meant to be instantiated. */ private URLEncoder() { } /** * Translates a string into "<CODE>x-www-form-urlencoded</CODE>" * format.This method uses the platform's default encoding * as the encoding scheme to obtain the bytes for unsafe characters. * * @param s the string to be translated. * * @return The resulting string. */ public static String encode(String s) { String str = null; str = encode(s, defaultEncName); return str; } /** * Translates a string into <code>application/x-www-form-urlencoded</code> * format using a specific encoding scheme. This method uses the * supplied encoding scheme to obtain the bytes for unsafe * characters. * <p> * <em><strong>Note:</strong> The <a href= * "http://www.w3.org/TR/html40/appendix/notes.html#non-ascii-chars"> * World Wide Web Consortium Recommendation</a> states that * UTF-8 should be used. Not doing so may introduce * incompatibilites.</em> * * @param s <code>String</code> to be translated. * @param enc The name of a supported character encoding such as UTF-8 * @return the translated <code>String</code>. */ public static String encode(String s, String enc) { boolean needToChange = false; boolean wroteUnencodedChar = false; int maxBytesPerChar = 10; // rather arbitrary limit, but safe for now StringBuffer out = new StringBuffer(s.length()); ByteArrayOutputStream buf = new ByteArrayOutputStream(maxBytesPerChar); OutputStreamWriter writer = null; try { writer = new OutputStreamWriter(buf, enc); } catch (UnsupportedEncodingException ex) { try { writer = new OutputStreamWriter(buf,defaultEncName); } catch (UnsupportedEncodingException e) { //never reach } } for (int i = 0; i < s.length(); i++) { int c = (int) s.charAt(i); //System.out.println("Examining character: " + c); if (c <256 && dontNeedEncoding[c]) { if (c == ' ') { c = '+'; needToChange = true; } //System.out.println("Storing: " + c); out.append((char)c); wroteUnencodedChar = true; } else { // convert to external encoding before hex conversion try { if (wroteUnencodedChar) { // Fix for 4407610 writer = new OutputStreamWriter(buf, enc); wroteUnencodedChar = false; } if(writer != null) writer.write(c); /* * If this character represents the start of a Unicode * surrogate pair, then pass in two characters. It's not * clear what should be done if a bytes reserved in the * surrogate pairs range occurs outside of a legal * surrogate pair. For now, just treat it as if it were * any other character. */ if (c >= 0xD800 && c <= 0xDBFF) { /* System.out.println(Integer.toHexString(c) + " is high surrogate"); */ if ( (i+1) < s.length()) { int d = (int) s.charAt(i+1); /* System.out.println("\tExamining " + Integer.toHexString(d)); */ if (d >= 0xDC00 && d <= 0xDFFF) { /* System.out.println("\t" + Integer.toHexString(d) + " is low surrogate"); */ writer.write(d); i++; } } } writer.flush(); } catch(IOException e) { buf.reset(); continue; } byte[] ba = buf.toByteArray(); for (int j = 0; j < ba.length; j++) { out.append('%'); char ch = forDigit((ba[j] >> 4) & 0xF, 16); if (isLetter(ch)) { ch -= caseDiff; } out.append(ch); ch = forDigit((ba[j] & 0xF), 16); //ch = forDigit(ba[j] & 0xF, 16); if (isLetter(ch)) { ch -= caseDiff; } out.append(ch); } buf.reset(); needToChange = true; } } return (needToChange? out.toString() : s); } private static boolean isLetter(char c){ if( (c >= 'a' && c <= 'z') || (c >='A' && c <= 'Z')) return true; return false; } private static char forDigit(int digit,int radix){ if ((digit >= radix) || (digit < 0)) { return '\0'; } if ((radix < MIN_RADIX) || (radix > MAX_RADIX)) { return '\0'; } if (digit < 10) { return (char)('0' + digit); } return (char)('a' - 10 + digit); }}?? 快捷鍵說明
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