Java——进制转换的一些内容

1.16进制字符串String转字节数组byte[]

String hex = "46534E3131323130393031303030313234";
// 把16进制字符串转换为字节数组 [70, 83, 78, 49, 49, 50, 49, 48, 57, 48, 49, 48, 48, 48, 49, 50, 52]
public byte[] hexToBytes(String hex){byte[] bytes = Hex.decode(hex);return bytes;
}

2.16进制字符串String转10进制数字int

String hex = "FFFF";
String hex2 = "0xFFFF";
public int hexToInt(String hex){int n = Integer.parseInt(hex, 16);//int n = Integer.parseInt(hex2.substring(2), 16);return n;
}

3.字节数组byte[]转字符串String

String hex = "46534E3131323130393031303030313234";
byte[] bytes5 = Hex.decode(hex);
String str = new String(bytes5);
public String bytesToString(byte[] bytes){String str = new String(bytes5);return str;
}

4.16进制字符串String–>byte[]–>String（使用ByteBuffer转换）

String hex = "46534E3131323130393031303030313234";
public String hexStringToString(String hex) throws CharacterCodingException {byte[] bytes = HexUtils.fromHexString(hex);// 把byte数组读取到ByteBuffer中ByteBuffer source = ByteBuffer.wrap(bytes);StringBuilder sb = new StringBuilder();//遍历字节数组的长度，把每个字节转成Stringfor (int i = 0; i < bytes.length; i++) {byte[] bytes1 = new byte[1];source.get(bytes1);ByteBuffer buffer1 = ByteBuffer.allocate(1).put(bytes1);buffer1.flip();CharsetDecoder charsetDecoder = StandardCharsets.UTF_8.newDecoder();String s = charsetDecoder.decode(buffer1).toString();sb.append(s);}return sb.toString();
}

5.字节数组byte[]转字符数组char[]

byte[] bytes = new byte[]{35,35};
public char[] bytesToChars(byte[] bytes) {Charset charset = Charset.forName("ISO-8859-1");ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);byteBuffer.put(bytes);byteBuffer.flip();CharBuffer charBuffer = charset.decode(byteBuffer);char[] array = charBuffer.array();return array;
}

6.字节byte转16进制字符串String

byte b = Byte.parseByte("1");
public String byteToHexString(byte b) {String str = String.format("0x%02X", b);//需要0x...后面几位数就在最后一个x前面写几，需要字母大写就把最后一个X大写//int c = b & 0xff;//String str = Integer.toHexString(c);//不需要0x,只显示数字return str;
}

7.字节数组byte[]转16进制数字int

byte[] bytes = new byte[]{35,35};
//方法1：10进制byte转16进制字符串，16进制字符串转16进制数字int
public int bytesToInt(byte[] bytes) {StringBuilder stringBuilder = new StringBuilder("");for (int i = 0; i < bytes.length; i++) {int b = bytes[i] & 0xff;String str = Integer.toHexString(b);if (str.length() < 2) {stringBuilder.append(0);}stringBuilder.append(str);}return Integer.parseInt(stringBuilder.toString(),16);
}
//方法2：位运算直接转（数组长度必须小于等于4）
public int bytesToInt(byte[] bytes) {ByteBuffer buffer = ByteBuffer.wrap(bytes);int value = 0;for (int i = 0; i < bytes.length; i++) {value = (value << 8) | (buffer.get() & 0xFF);}return value;
}

8.字节数组byte[]转16进制字符串String

byte[] bytes = new byte[]{35,35};
public String toHexString(byte[] bytes) {if (null == bytes) {return null;}StringBuilder sb = new StringBuilder(bytes.length << 1);for (byte aByte : bytes) {sb.append(hex[(aByte & 0xf0) >> 4]).append(hex[(aByte & 0x0f)]);}return sb.toString();
}