十六进制转换成十进制 二进制

// 十六进制转二进制
public String HToB(String a) {
String b = Integer.toBinaryString(Integer.valueOf(toD(a, 16)));
return b;
}

// 二进制转十六进制
public String BToH(String a) {
// 将二进制转为十进制再从十进制转为十六进制
String b = Integer.toHexString(Integer.valueOf(toD(a, 2)));
return b;
}

// 任意进制数转为十进制数
public String toD(String a, int b) {
int r = 0;
for (int i = 0; i < a.length(); i++) {
r = (int) (r + formatting(a.substring(i, i + 1))
* Math.pow(b, a.length() - i - 1));
}
return String.valueOf(r);
}

// 将十六进制中的字母转为对应的数字
public int formatting(String a) {
int i = 0;
for (int u = 0; u < 10; u++) {
if (a.equals(String.valueOf(u))) {
i = u;
}
}
if (a.equals("a")) {
i = 10;
}
if (a.equals("b")) {
i = 11;
}
if (a.equals("c")) {
i = 12;
}
if (a.equals("d")) {
i = 13;
}
if (a.equals("e")) {
i = 14;
}
if (a.equals("f")) {
i = 15;
}
return i;
}

// 将十进制中的数字转为十六进制对应的字母
public String formattingH(int a) {
String i = String.valueOf(a);

switch (a) {

10: i = "a";

break;

11: i = "b";

break;

12: i = "c";

break;

13: i = "d";

break;

14: i = "e";

break;

15: i = "f";

break;

}
return i;
}