java工具類之編碼轉換工具類

/**
 * @Description:編碼轉換工具類
 * @Author:zql
 *
 */
public class UnicodeDecoderUtil {
	
    /**
     * @Description:編碼字串
     *
     * @param str
     * @return
     */
    public static String escape(String str) {
        int i;
        char j;
        StringBuffer tmp = new StringBuffer();
        tmp.ensureCapacity(str.length() * 6);
        for (i = 0; i < str.length(); i++) {
            j = str.charAt(i);
            // 判斷字元是否為數字或小寫字母或大小字母
            if (Character.isDigit(j) || Character.isLowerCase(j) || Character.isUpperCase(j)) {
                tmp.append(j);
            } else {
                tmp.append("&#x");
                tmp.append(Integer.toString(j, 16));
                tmp.append(";");
            }
        }
        return tmp.toString();
    }
 
    /**
     * @Description:解碼字串
     *
     * @param hexStr
     * @return
     */
    public static String unescape(String hexStr) {
    	StringBuffer tmp = new StringBuffer();
		String prefStr = "&#x";
		String laterStr = ";";
		tmp.ensureCapacity(hexStr.length());
		int lastPos = 0, pref = 0, later = 0;
		char ch;
		while (lastPos < hexStr.length()) {
			pref = hexStr.indexOf(prefStr, lastPos);
			later = hexStr.indexOf(laterStr, pref);
			if (pref == lastPos) {
				ch = (char) Integer.parseInt(hexStr.substring(pref + 3, later), 16);
                tmp.append(ch);
				lastPos = later + 1;
			} else {
				if (pref == -1) {
					tmp.append(hexStr.substring(lastPos));
					lastPos = hexStr.length();
				} else {
					tmp.append(hexStr.substring(lastPos, pref));
					lastPos = pref;
				}
			}
		}
        return tmp.toString();
    }
    
    /**
     * @Description:十六進位制的編碼轉成十進位制的編碼
     *
     * @param hexStr
     * @return
     */
    public static String unescapeHexToDec(String hexStr) {
		StringBuffer tmp = new StringBuffer();
		String prefStr = "&#x";
		String laterStr = ";";
		tmp.ensureCapacity(hexStr.length());
		int lastPos = 0, pref = 0, later = 0;
		while (lastPos < hexStr.length()) {
			pref = hexStr.indexOf(prefStr, lastPos);
			later = hexStr.indexOf(laterStr, pref);
			if (pref == lastPos) {
				tmp.append(prefStr);
				tmp.append(Integer.parseInt(hexStr.substring(pref + 3, later), 16));
				tmp.append(laterStr);
				lastPos = later + 1;
			} else {
				if (pref == -1) {
					tmp.append(hexStr.substring(lastPos));
					lastPos = hexStr.length();
				} else {
					tmp.append(hexStr.substring(lastPos, pref));
					lastPos = pref;
				}
			}
		}
		return tmp.toString();
    } 
    
    /**
     * @Description:十進位制的編碼轉成十六進位制的編碼
     *
     * @param hexStr
     * @return
     */
    public static String unescapeDecToHex(String decStr) {
		StringBuffer tmp = new StringBuffer();
		String prefStr = "&#x";
		String laterStr = ";";
		tmp.ensureCapacity(decStr.length());
		int lastPos = 0, pref = 0, later = 0;
		while (lastPos < decStr.length()) {
			pref = decStr.indexOf(prefStr, lastPos);
			later = decStr.indexOf(laterStr, pref);
			if (pref == lastPos) {
				tmp.append(prefStr);
				tmp.append(Integer.toHexString(Integer.parseInt(decStr.substring(pref + 3, later))));
				tmp.append(laterStr);
				lastPos = later + 1;
			} else {
				if (pref == -1) {
					tmp.append(decStr.substring(lastPos));
					lastPos = decStr.length();
				} else {
					tmp.append(decStr.substring(lastPos, pref));
					lastPos = pref;
				}
			}
		}
		return tmp.toString();
    } 
 
    public static void main(String[] args) {
        String str = "測試字串";
        String str2 = "&#x6d4b;&#x8bd5;隔開&#x5b57;&#x7b26;&#x4e32;內容";
       
        System.out.println("編碼：" + escape(str));
        System.out.println("解碼：" + unescape(str2));
        String str3 = unescapeHexToDec(str2);
        System.out.println("轉成10進位制編碼：" + str3);
        String str4 = unescapeDecToHex(str3);
        System.out.println("轉成16進位制編碼：" + str4);
    }
}