# 浅谈二进制、十进制、十六进制、字符串之间的相互转换

1. 字节转10进制

```/*
* 字节转10进制
*/
public static int byte2Int(byte b){
int r = (int) b;
return r;
}```

2. 10进制转字节

```/*
* 10进制转字节
*/
public static byte int2Byte(int i){
byte r = (byte) i;
return r;
}```

3. 字节数组转16进制字符串

```/*
* 字节数组转16进制字符串
*/
public static String bytes2HexString(byte[] b) {
String r = "";

for (int i = 0; i < b.length; i++) {
String hex = Integer.toHexString(b[i] & 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
r += hex.toUpperCase();
}

return r;
}```

4. 16进制字符串转字节数组

```/*
* 字符转换为字节
*/
private static byte charToByte(char c) {
return (byte) "0123456789ABCDEF".indexOf(c);
}

/*
* 16进制字符串转字节数组
*/
public static byte[] hexString2Bytes(String hex) {

if ((hex == null) || (hex.equals(""))){
return null;
}
else if (hex.length()%2 != 0){
return null;
}
else{
hex = hex.toUpperCase();
int len = hex.length()/2;
byte[] b = new byte[len];
char[] hc = hex.toCharArray();
for (int i=0; i<len; i++){
int p=2*i;
b[i] = (byte) (charToByte(hc[p]) << 4 | charToByte(hc[p+1]));
}
return b;
}

}```

5. 字节数组转字符串

```/*
* 字节数组转字符串
*/
public static String bytes2String(byte[] b) throws Exception {
String r = new String (b,"UTF-8");
return r;
}```

6. 字符串转字节数组

```/*
* 字符串转字节数组
*/
public static byte[] string2Bytes(String s){
byte[] r = s.getBytes();
return r;
}```

7. 16进制字符串转字符串

```/*
* 16进制字符串转字符串
*/
public static String hex2String(String hex) throws Exception{
String r = bytes2String(hexString2Bytes(hex));
return r;
}```

8. 字符串转16进制字符串

```/*
* 字符串转16进制字符串
*/
public static String string2HexString(String s) throws Exception{
String r = bytes2HexString(string2Bytes(s));
return r;
}```

main函数：

```public static void main(String[] args) throws Exception{
byte b1 = (byte) 45;
System.out.println("1.字节转10进制:" + byte2Int(b1));

int i = 89;
System.out.println("2.10进制转字节:" + int2Byte(i));

byte[] b2 = new byte[]{(byte)0xFF, (byte)0x5F, (byte)0x6, (byte)0x5A};
System.out.println("3.字节数组转16进制字符串:" + bytes2HexString(b2));

String s1 = new String("1DA47C");
System.out.println("4.16进制字符串转字节数组:" + Arrays.toString(hexString2Bytes(s1)));

System.out.println("5.字节数组转字符串:" + bytes2String(b2));

System.out.println("6.字符串转字节数组:" + Arrays.toString(string2Bytes(s1)));

System.out.println("7.16进制字符串转字符串:" + hex2String(s1));

String s2 = new String("Hello!");
System.out.println("8.字符串转16进制字符串:" + string2HexString(s2));
}```

```1.字节转10进制:45
2.10进制转字节:89
3.字节数组转16进制字符串:FF5F065A
4.16进制字符串转字节数组:[29, -92, 124]
5.字节数组转字符串:?_Z
6.字符串转字节数组:[49, 68, 65, 52, 55, 67]
7.16进制字符串转字符串:?|
8.字符串转16进制字符串:48656C6C6F21```