我的正式解决方案:

/**
 * Decodes a hexadecimally encoded binary string.
 * <p>
 * Note that this function does <em>NOT</em> convert a hexadecimal number to a
 * binary number.
 *
 * @param hex Hexadecimal representation of data.
 * @return The byte[] representation of the given data.
 * @throws NumberFormatException If the hexadecimal input string is of odd
 * length or invalid hexadecimal string.
 */
public static byte[] hex2bin(String hex) throws NumberFormatException {
    if (hex.length() % 2 > 0) {
        throw new NumberFormatException("Hexadecimal input string must have an even length.");
    }
    byte[] r = new byte[hex.length() / 2];
    for (int i = hex.length(); i > 0;) {
        r[i / 2 - 1] = (byte) (digit(hex.charAt(--i)) | (digit(hex.charAt(--i)) << 4));
    }
    return r;
}

private static int digit(char ch) {
    int r = Character.digit(ch, 16);
    if (r < 0) {
        throw new NumberFormatException("Invalid hexadecimal string: " + ch);
    }
    return r;
}

类似于PHP的hex2bin()函数，但采用Java风格。

例子:

String data = new String(hex2bin("6578616d706c65206865782064617461"));
// data value: "example hex data"

一行程序: 进口javax.xml.bind.DatatypeConverter; (字节[]数组) 返回DatatypeConverter.printHexBinary(数组); ｝ public static byte[] toByteArray(String s) { 返回DatatypeConverter.parseHexBinary (s); ｝

对于那些对来自FractalizeR的一行代码背后的实际代码感兴趣的人(我需要它，因为javax.xml.bind不适用于Android(默认情况下))，这来自com.sun.xml.internal.bind. datatypeconverterimpll .java:

public byte[] parseHexBinary(String s) {
    final int len = s.length();

    // "111" is not a valid hex encoding.
    if( len%2 != 0 )
        throw new IllegalArgumentException("hexBinary needs to be even-length: "+s);

    byte[] out = new byte[len/2];

    for( int i=0; i<len; i+=2 ) {
        int h = hexToBin(s.charAt(i  ));
        int l = hexToBin(s.charAt(i+1));
        if( h==-1 || l==-1 )
            throw new IllegalArgumentException("contains illegal character for hexBinary: "+s);

        out[i/2] = (byte)(h*16+l);
    }

    return out;
}

private static int hexToBin( char ch ) {
    if( '0'<=ch && ch<='9' )    return ch-'0';
    if( 'A'<=ch && ch<='F' )    return ch-'A'+10;
    if( 'a'<=ch && ch<='f' )    return ch-'a'+10;
    return -1;
}

private static final char[] hexCode = "0123456789ABCDEF".toCharArray();

public String printHexBinary(byte[] data) {
    StringBuilder r = new StringBuilder(data.length*2);
    for ( byte b : data) {
        r.append(hexCode[(b >> 4) & 0xF]);
        r.append(hexCode[(b & 0xF)]);
    }
    return r.toString();
}

public static byte[] hex2ba(String sHex) throws Hex2baException {
    if (1==sHex.length()%2) {
        throw(new Hex2baException("Hex string need even number of chars"));
    }

    byte[] ba = new byte[sHex.length()/2];
    for (int i=0;i<sHex.length()/2;i++) {
        ba[i] = (Integer.decode(
                "0x"+sHex.substring(i*2, (i+1)*2))).byteValue();
    }
    return ba;
}

我知道这是一个非常老的帖子，但仍然喜欢添加我的便士价值。

如果我真的需要编码一个简单的十六进制字符串到二进制转换器，我想这样做。

public static byte[] hexToBinary(String s){

  /*
   * skipped any input validation code
   */

  byte[] data = new byte[s.length()/2];

  for( int i=0, j=0; 
       i<s.length() && j<data.length; 
       i+=2, j++)
  {
     data[j] = (byte)Integer.parseInt(s.substring(i, i+2), 16);
  }

  return data;
}

common -codec中的Hex类应该为您做到这一点。

http://commons.apache.org/codec/

import org.apache.commons.codec.binary.Hex;
...
byte[] decoded = Hex.decodeHex("00A0BF");
// 0x00 0xA0 0xBF

迟到了，但我已经把DaveL上面的答案合并到一个具有反向操作的类中——以防它有所帮助。

public final class HexString {
    private static final char[] digits = "0123456789ABCDEF".toCharArray();

    private HexString() {}

    public static final String fromBytes(final byte[] bytes) {
        final StringBuilder buf = new StringBuilder();
        for (int i = 0; i < bytes.length; i++) {
            buf.append(HexString.digits[(bytes[i] >> 4) & 0x0f]);
            buf.append(HexString.digits[bytes[i] & 0x0f]);
        }
        return buf.toString();
    }

    public static final byte[] toByteArray(final String hexString) {
        if ((hexString.length() % 2) != 0) {
            throw new IllegalArgumentException("Input string must contain an even number of characters");
        }
        final int len = hexString.length();
        final byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4)
                    + Character.digit(hexString.charAt(i + 1), 16));
        }
        return data;
    }
}

和JUnit测试类:

public class TestHexString {

    @Test
    public void test() {
        String[] tests = {"0FA1056D73", "", "00", "0123456789ABCDEF", "FFFFFFFF"};

        for (int i = 0; i < tests.length; i++) {
            String in = tests[i];
            byte[] bytes = HexString.toByteArray(in);
            String out = HexString.fromBytes(bytes);
            System.out.println(in); //DEBUG
            System.out.println(out); //DEBUG
            Assert.assertEquals(in, out);

        }

    }

}