URLDecoder 编码的实现

import java.io.ByteArrayOutputStream; import java.io.DataOutputStream; public class URLDecoder { /** * 解码URL串 * * @param url * 待解码的URL串 * @return 解码后的字符串 */ public static String decode(String url) { char[] chars = url.toCharArray(); int cursor = 0; ByteArrayOutputStream baos = new ByteArrayOutputStream(); DataOutputStream dos = null; try { dos = new DataOutputStream(baos); while (cursor < chars.length) { int curr = chars[cursor++]; if (curr == '%') { StringBuffer tmp = new StringBuffer(); char cr = chars[cursor++]; char lf = chars[cursor++]; tmp.append(cr).append(lf); Integer result = Integer.valueOf(tmp.toString(), 16); curr = result.intValue(); } dos.writeByte(curr); } dos.flush(); baos.flush(); byte[] data = baos.toByteArray(); String text = URLDecoder.decode(data, 0, data.length); return text; } catch (Exception e) { e.printStackTrace(); } finally { try { if (dos != null) dos.close(); if (baos != null) baos.close(); } catch (Exception e) { } } return null; } public static String decode(byte in[], int offset, int length) { StringBuffer buff = new StringBuffer(); int max = offset + length; for (int i = offset; i < max; i++) { char c = 0; if ((in[i] & 0x80) == 0) { c = (char) in[i]; } else if ((in[i] & 0xe0) == 0xc0) {// 11100000 c |= ((in[i++] & 0x1f) << 6); // 00011111 c |= ((in[i] & 0x3f) << 0); // 00111111 } else if ((in[i] & 0xf0) == 0xe0) {// 11110000 c |= ((in[i++] & 0x0f) << 12); // 00001111 c |= ((in[i++] & 0x3f) << 6); // 00111111 c |= ((in[i] & 0x3f) << 0); // 00111111 } else if ((in[i] & 0xf8) == 0xf0) {// 11111000 c |= ((in[i++] & 0x07) << 18); // 00000111 (move 18, not // 16?) c |= ((in[i++] & 0x3f) << 12); // 00111111 c |= ((in[i++] & 0x3f) << 6); // 00111111 c |= ((in[i] & 0x3f) << 0); // 00111111 } else { c = '?'; } buff.append(c); } return buff.toString(); } }