How to convert hex string to Java string?

java string hex

175,086

Solution 1

Using Hex in Apache Commons:

String hexString = "fd00000aa8660b5b010006acdc0100000101000100010000";    
byte[] bytes = Hex.decodeHex(hexString.toCharArray());
System.out.println(new String(bytes, "UTF-8"));

Solution 2

byte[] bytes = javax.xml.bind.DatatypeConverter.parseHexBinary(hexString);
String result= new String(bytes, encoding);

Solution 3

You can go from String (hex) to byte array to String as UTF-8(?). Make sure your hex string does not have leading spaces and stuff.

public static byte[] hexStringToByteArray(String hex) {
    int l = hex.length();
    byte[] data = new byte[l / 2];
    for (int i = 0; i < l; i += 2) {
        data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4)
                + Character.digit(hex.charAt(i + 1), 16));
    }
    return data;
}

Usage:

String b = "0xfd00000aa8660b5b010006acdc0100000101000100010000";
byte[] bytes = hexStringToByteArray(b);
String st = new String(bytes, StandardCharsets.UTF_8);
System.out.println(st);

Solution 4

First of all read in the data, then convert it to byte array:

 byte b = Byte.parseByte(str, 16);

and then use String constructor:

new String(byte[] bytes)

or if the charset is not system default then:

new String(byte[] bytes, String charsetName)

Solution 5

Try the following code:

public static byte[] decode(String hex){

        String[] list=hex.split("(?<=\\G.{2})");
        ByteBuffer buffer= ByteBuffer.allocate(list.length);
        System.out.println(list.length);
        for(String str: list)
            buffer.put(Byte.parseByte(str,16));

        return buffer.array();

}

To convert to String just create a new String with the byte[] returned by the decode method.

View more solutions

175,086

Author by

Qi Wang

I am very poor when it comes to complex algorithms :) So plz try to make this things simpler to me

Updated on September 28, 2020

Comments

Qi Wang over 3 years
For logging purpose we are converting the logs to byte array and then to hex string. I want to get it back in a Java String, but I am not able to do so.

The hex string in log file looks something like
```
fd00000aa8660b5b010006acdc0100000101000100010000
```
How can I decode this?
Joker_vD over 11 years

Of course, it may or may not work depending on encoding used by "some other guys". Maybe they used Latin-9. Or UTF-8. Or EUC-JP. Or maybe it was in Big-Endian. Who knows?
Aleksander Gralak over 11 years

That's why you should specify the encoding which was used by log strings before conversion to hex string.
gogognome over 11 years

use Byte.parseByte(str, 16); to parse a hexadecimal number.
domenukk over 8 years

I changed Byte.parseByte to (byte)Integer.parseInteger to allow for numbers > 128 to be parsed.
kodepet over 8 years

The String constructor expects a byte array and not just byte, I tried and it failed.
Aleksander Gralak over 8 years

@Callforeach yes it it exactly what I gave as en example, byte[] stands for array not single byte: new String(byte[] bytes)
Jonathan over 7 years

Lots of substrings being created. Not ideal.
Error over 7 years

@domenukk it's Integer.parseInt(..) not Integer.parseInteger(..) . Byte.parseByte implemented as follow { return (byte) Integer.parseInt(Str, base);}
Error over 7 years

@Munene thanx 4 regex
Kaveesh Kanwal over 7 years

how to do ot for versions below kitkat?
zundi almost 7 years

Where the heck do I find DatatypeConverter?
zundi almost 7 years

I'm not following... where did you get the bytes byte array from?
Aleksander Gralak almost 7 years

@zundi in first line you parse only single byte. So you need to use a loop to get all the bytes and put them in array. Please look at Munene iUwej Julius answer. His method is doing just that
DwB over 5 years

Hex is now part of Apache Commons Codec
Jean-Alexis Aufauvre about 5 years

Not public anymore in recent Java versions
Jacques Koorts almost 5 years

Here the dependency: <dependency> <groupId>commons-codec</groupId> <artifactId>commons-codec</artifactId> <version>1.12</version> </dependency>
Holger over 4 years

It doesn’t need much to recognize, that this data is not a UTF-8 encoded string and new String(bytes, "UTF-8") will just produce garbage.
Admin over 4 years

may I ask what is the purpose of converting it to String as UTF-8?
roninjoe over 4 years

replace "String str" with a StringBuffer(), and use sb.append(char) if performance is an issue.
telebog over 4 years

javax.xml.bind.DatatypeConverter
gumuruh over 3 years

what are the encoding values?
telebog over 3 years

docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.h‌tml