Java 十进制转十六进制

1、

/**
* All possible chars for representing a number as a String
*/
final static char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
'9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y',
'z' };

public static String toHexString(int i) {

return toUnsignedString(i, 4);
}

/**
* Convert the integer to an unsigned number.
*/
private static String toUnsignedString(int i, int shift) {

char[] buf = new char[32];// 声明一个Int值长度的字符数组
int charPos = 32;
// 得到每位都是1的二进制数
int radix = 1 << shift;
int mask = radix - 1;
do {
buf[--charPos] = digits[i & mask];// 将i值的当前最低shift位的值赋值给声明的字符数组的前一位
i >>>= shift;// i右移shift位并赋值
}
while (i != 0);

return new String(buf, charPos, (32 - charPos));
}

2、

public static String decimalToHex(int decimal) {

String hex = "";
while (decimal != 0) {
int hexValue = decimal % 16;
hex = toHexChar(hexValue) + hex;
decimal = decimal / 16;
}
return hex;
}

public static char toHexChar(int hexValue) {

if (hexValue <= 9 && hexValue >= 0) {
return (char) (hexValue + '0');
}
else {// (hexValue <= 15 && hexValue >= 10)
return (char) (hexValue - 10 + 'A');
}
}