由于MIDP没有J2SE对应的java.net.URLEncoder类,因此,要向服务器发送HTTP请求,必须自己进行URL编码,参考JDK1.4.2的src代码,将其改为一个能用在MIDP环境中的URLEncoder类: // URLEncoder.java package com.mboker.blog.midp.http; import java.io.*; /** * Encode url, just like java.net.URLEncoder.encode() in J2SE. * NOTE: This class is modified from java.net.URLEncoder class in J2SE 1.4. * * @author Xuefeng */ class URLEncoder { private static final int MAX_BYTES_PER_CHAR = 10; // rather arbitrary limit, but safe for now private static boolean[] dontNeedEncoding; private static final int caseDiff = ('a' - 'A'); static { dontNeedEncoding = new boolean[256]; for (int i='a'; i<='z'; i++) { dontNeedEncoding[i] = true; } for (int i='A'; i<='Z'; i++) { dontNeedEncoding[i] = true; } for (int i='0'; i<='9'; i++) { dontNeedEncoding[i] = true; } dontNeedEncoding[' '] = true; dontNeedEncoding['-'] = true; dontNeedEncoding['_'] = true; dontNeedEncoding['.'] = true; dontNeedEncoding['*'] = true; } private URLEncoder() {} public static String encode(String s) { boolean wroteUnencodedChar = false; StringBuffer out = new StringBuffer(s.length()); ByteArrayOutputStream buf = new ByteArrayOutputStream(MAX_BYTES_PER_CHAR); OutputStreamWriter writer = new OutputStreamWriter(buf); for (int i = 0; i < s.length(); i++) { int c = (int) s.charAt(i); if (c<256 && dontNeedEncoding[c]) { out.append((char) (c==' ' ? '+' : c)); wroteUnencodedChar = true; } else { // convert to external encoding before hex conversion try { if (wroteUnencodedChar) { // Fix for 4407610 writer = new OutputStreamWriter(buf); wroteUnencodedChar = false; } 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) { if ((i + 1) < s.length()) { int d = (int) s.charAt(i + 1); if (d >= 0xDC00 && d <= 0xDFFF) { 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 = toHex((ba[j] >> 4) & 0xF); // converting to use uppercase letter as part of // the hex value if ch is a letter. if (isLetter(ch)) { ch -= caseDiff; } out.append(ch); ch = toHex(ba[j] & 0xF); if (isLetter(ch)) { ch -= caseDiff; } out.append(ch); } buf.reset(); } } return out.toString(); } private static char toHex(int digit) { if ((digit >= 16) || (digit < 0)) { return '\0'; } if (digit < 10) { return (char)('0' + digit); } return (char)('a' - 10 + digit); } private static boolean isLetter(char c) { return (c>='a' && c<='z'); } } J2SE的URLEncoder依赖于java.lang.Character的许多特性,将其全部剔除并改造为基本运算,即可在MIDP环境中使用,中文测试也一切正常。 |
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