unicode与string之间的相互转换

unicode码对每一个字符用4位16进制数表示。具体规则是：将一个字符(char)的高8位与低8位分别取出，转化为16进制数， 如果转化的16进制数的长度不足2位，则在其后补0，然后将高、低8位转成的16进制字符串拼接起来并在前面补上"\u" 即可。 

方法一：转换原理代码实现

/**
 * 将字符串转成unicode
 * @param str 待转字符串
 * @return unicode字符串
 */
public String convert(String str)
{
    str = (str == null ? "" : str);
    String tmp;
    StringBuffer sb = new StringBuffer(1000);
    char c;
    int i, j;
    (0);
    for (i = 0; i < (); i++)
    {
        c = (i);
        ("\\u");
        j = (c >>>8); //取出高8位
        tmp = Integer.toHexString(j);
        if (() == 1)
            ("0");
        (tmp);
        j = (c & 0xFF); //取出低8位
        tmp = Integer.toHexString(j);
        if (() == 1)
            ("0");
        (tmp);

    }
    return (new String(sb));
}
/**
 * 将unicode 字符串
 * @param str 待转字符串
 * @return 普通字符串
 */
public String revert(String str)
{
    str = (str == null ? "" : str);
    if (("\\u") == -1)//如果不是unicode码则原样返回
        return str;

    StringBuffer sb = new StringBuffer(1000);

    for (int i = 0; i <=() - 6;)
    {
        String strTemp = (i, i + 6);
        String value = (2);
        int c = 0;
        for (int j = 0; j < (); j++)
        {
            char tempChar = (j);
            int t = 0;
            switch (tempChar)
            {
                case 'a':
                    t = 10;
                    break;
                case 'b':
                    t = 11;
                    break;
                case 'c':
                    t = 12;
                    break;
                case 'd':
                    t = 13;
                    break;
                case 'e':
                    t = 14;
                    break;
                case 'f':
                    t = 15;
                    break;
                default:
                    t = tempChar - 48;
                    break;
            }

            c += t * ((int) Math.pow(16, (() - j - 1)));
        }
        ((char) c);
        i = i + 6;
    }
    return ();
}

方法二：api实现

/**
 * 字符串转换unicode
 */
public static String convert(String string) {

    StringBuffer unicode = new StringBuffer();

    for (int i = 0; i < (); i++) {

        // 取出每一个字符
        char c = (i);

        // 转换为unicode
        (String.format("\\u%04x",Integer.valueOf(c)));
    }

    return ();
}
/**
 * unicode 转字符串
 */
public static String revert(String unicode) {

    StringBuffer string = new StringBuffer();

    String[] hex = ("\\\\u");

    for (int i = 1; i < hex.length; i++) {

        // 转换出每一个代码点
        int data = Integer.parseInt(hex[i], 16);

        // 追加成string
        ((char) data);
    }

    return ();
}