在 Java 中将字符串转换为十六进制

我正在尝试用 java 将类似“ testing123”的字符串转换成十六进制形式。

把它转换回来，除了向后是不是一回事？

481146 次浏览
小开

我建议这样做，其中 str是您的输入字符串:

StringBuffer hex = new StringBuffer();
char[] raw = tokens[0].toCharArray();
for (int i=0;i<raw.length;i++) {
if     (raw[i]<=0x000F) { hex.append("000"); }
else if(raw[i]<=0x00FF) { hex.append("00" ); }
else if(raw[i]<=0x0FFF) { hex.append("0"  ); }
hex.append(Integer.toHexString(raw[i]).toUpperCase());
}
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The numbers that you encode into hexadecimal must represent some encoding of the characters, such as UTF-8. So first convert the String to a byte[] representing the string in that encoding, then convert each byte to hexadecimal.

public static String hexadecimal(String input, String charsetName) throws UnsupportedEncodingException {
if (input == null) throw new NullPointerException();
return asHex(input.getBytes(charsetName));
}


private static final char[] HEX_CHARS = "0123456789abcdef".toCharArray();


public static String asHex(byte[] buf)
{
char[] chars = new char[2 * buf.length];
for (int i = 0; i < buf.length; ++i)
{
chars[2 * i] = HEX_CHARS[(buf[i] & 0xF0) >>> 4];
chars[2 * i + 1] = HEX_CHARS[buf[i] & 0x0F];
}
return new String(chars);
}
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byte[] bytes = string.getBytes(CHARSET); // you didn't say what charset you wanted
BigInteger bigInt = new BigInteger(bytes);
String hexString = bigInt.toString(16); // 16 is the radix

此时可以返回 hexString，但需要注意的是，前导空字符将被去掉，如果第一个字节小于16，结果将有一个奇数长度。如果您需要处理这些情况，您可以添加一些额外的代码来填充0:

StringBuilder sb = new StringBuilder();
while ((sb.length() + hexString.length()) < (2 * bytes.length)) {
sb.append("0");
}
sb.append(hexString);
return sb.toString();
小开

这里有一个把它转换成十六进制的简单方法:

public String toHex(String arg) {
return String.format("%040x", new BigInteger(1, arg.getBytes(/*YOUR_CHARSET?*/)));
}
小开

为了确保十六进制总是40个字符长，BigInteger 必须是正数:

public String toHex(String arg) {
return String.format("%x", new BigInteger(1, arg.getBytes(/*YOUR_CHARSET?*/)));
}
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import org.apache.commons.codec.binary.Hex;
...


String hexString = Hex.encodeHexString(myString.getBytes(/* charset */));

Http://commons.apache.org/codec/apidocs/org/apache/commons/codec/binary/hex.html

小开

这是另一个解决方案

public static String toHexString(byte[] ba) {
StringBuilder str = new StringBuilder();
for(int i = 0; i < ba.length; i++)
str.append(String.format("%x", ba[i]));
return str.toString();
}


public static String fromHexString(String hex) {
StringBuilder str = new StringBuilder();
for (int i = 0; i < hex.length(); i+=2) {
str.append((char) Integer.parseInt(hex.substring(i, i + 2), 16));
}
return str.toString();
}
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Much better:

public static String fromHexString(String hex, String sourceEncoding ) throws  IOException{
ByteArrayOutputStream bout = new ByteArrayOutputStream();
byte[] buffer = new byte[512];
int _start=0;
for (int i = 0; i < hex.length(); i+=2) {
buffer[_start++] = (byte)Integer.parseInt(hex.substring(i, i + 2), 16);
if (_start >=buffer.length || i+2>=hex.length()) {
bout.write(buffer);
Arrays.fill(buffer, 0, buffer.length, (byte)0);
_start  = 0;
}
}


return  new String(bout.toByteArray(), sourceEncoding);
}
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获取十六进制的整数值

        //hex like: 0xfff7931e to int
int hexInt = Long.decode(hexString).intValue();
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import java.io.*;
import java.util.*;


public class Exer5{


public String ConvertToHexadecimal(int num){
int r;
String bin="\0";


do{
r=num%16;
num=num/16;


if(r==10)
bin="A"+bin;


else if(r==11)
bin="B"+bin;


else if(r==12)
bin="C"+bin;


else if(r==13)
bin="D"+bin;


else if(r==14)
bin="E"+bin;


else if(r==15)
bin="F"+bin;


else
bin=r+bin;
}while(num!=0);


return bin;
}


public int ConvertFromHexadecimalToDecimal(String num){
int a;
int ctr=0;
double prod=0;


for(int i=num.length(); i>0; i--){


if(num.charAt(i-1)=='a'||num.charAt(i-1)=='A')
a=10;


else if(num.charAt(i-1)=='b'||num.charAt(i-1)=='B')
a=11;


else if(num.charAt(i-1)=='c'||num.charAt(i-1)=='C')
a=12;


else if(num.charAt(i-1)=='d'||num.charAt(i-1)=='D')
a=13;


else if(num.charAt(i-1)=='e'||num.charAt(i-1)=='E')
a=14;


else if(num.charAt(i-1)=='f'||num.charAt(i-1)=='F')
a=15;


else
a=Character.getNumericValue(num.charAt(i-1));
prod=prod+(a*Math.pow(16, ctr));
ctr++;
}
return (int)prod;
}


public static void main(String[] args){


Exer5 dh=new Exer5();
Scanner s=new Scanner(System.in);


int num;
String numS;
int choice;


System.out.println("Enter your desired choice:");
System.out.println("1 - DECIMAL TO HEXADECIMAL             ");
System.out.println("2 - HEXADECIMAL TO DECIMAL              ");
System.out.println("0 - EXIT                          ");


do{
System.out.print("\nEnter Choice: ");
choice=s.nextInt();


if(choice==1){
System.out.println("Enter decimal number: ");
num=s.nextInt();
System.out.println(dh.ConvertToHexadecimal(num));
}


else if(choice==2){
System.out.println("Enter hexadecimal number: ");
numS=s.next();
System.out.println(dh.ConvertFromHexadecimalToDecimal(numS));
}
}while(choice!=0);
}
}
小开

All answers based on String.getBytes() involve 编码 your string according to a Charset. You don't necessarily get the hex value of the 2-byte 角色 that make up your string. If what you actually want is the equivalent of a hex viewer, then you need to access the chars directly. Here's the function that I use in my code for debugging Unicode issues:

static String stringToHex(String string) {
StringBuilder buf = new StringBuilder(200);
for (char ch: string.toCharArray()) {
if (buf.length() > 0)
buf.append(' ');
buf.append(String.format("%04x", (int) ch));
}
return buf.toString();
}

然后，stringToHex (“ testing123”)会给你:

0074 0065 0073 0074 0069 006e 0067 0031 0032 0033
小开

将十六进制代码中的字母转换为十六进制代码中的字母。

        String letter = "a";
String code;
int decimal;


code = Integer.toHexString(letter.charAt(0));
decimal = Integer.parseInt(code, 16);


System.out.println("Hex code to " + letter + " = " + code);
System.out.println("Char to " + code + " = " + (char) decimal);
小开

如果要走另一条路(十六进制到字符串) ，可以使用

public String hexToString(String hex) {
return new String(new BigInteger(hex, 16).toByteArray());
}
小开

首先使用 getBytes ()函数将其转换为字节，然后将其转换为十六进制:

private static String hex(byte[] bytes) {
StringBuilder sb = new StringBuilder();
for (int i=0; i<bytes.length; i++) {
sb.append(String.format("%02X ",bytes[i]));
}
return sb.toString();
}
小开 
new BigInteger(1, myString.getBytes(/*YOUR_CHARSET?*/)).toString(16)
小开

转换字符串到十六进制 :

public String hexToString(String hex) {
return Integer.toHexString(Integer.parseInt(hex));
}

这绝对是最简单的方法。

小开

使用 DatatypeConverter.printHexBinary():

public static String toHexadecimal(String text) throws UnsupportedEncodingException
{
byte[] myBytes = text.getBytes("UTF-8");


return DatatypeConverter.printHexBinary(myBytes);
}

示例用法:

System.out.println(toHexadecimal("Hello StackOverflow"));

印刷品:

48656C6C6F20537461636B4F766572666C6F77

Note: This causes a little extra trouble with Java 9 and newer since the API is not included by default. For reference e.g. see 这个 GitHub issue.

小开

下面是一些比较不同方法和库的基准测试。番石榴在解码方面打败了 Apache Commons 编解码器。Commons Codec 在编码方面打败了番石榴。JHex 在解码和编码两方面都胜过他们。

JHex 的例子

String hexString = "596f752772652077656c636f6d652e";
byte[] decoded = JHex.decodeChecked(hexString);
System.out.println(new String(decoded));
String reEncoded = JHex.encode(decoded);

所有东西都在 JHex 的单一类文件里。如果您不想在依赖关系树中再添加一个库，那么可以随意复制粘贴。还要注意的是，它只能以 Java9 jar 的形式提供，直到我能够弄清楚如何使用 Gradle 和 Bintray 插件发布多个发布目标。

小开

将 String 转换为十六进制表示法的一种简单方便的方法是:

public static void main(String... args){
String str = "Hello! This is test string.";
char ch[] = str.toCharArray();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < ch.length; i++) {
sb.append(Integer.toHexString((int) ch[i]));
}
System.out.println(sb.toString());
}
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检查 String 到十六进制和十六进制到 String 的解决方案，反之亦然

public class TestHexConversion {
public static void main(String[] args) {
try{
String clearText = "testString For;0181;with.love";
System.out.println("Clear Text  = " + clearText);
char[] chars = clearText.toCharArray();
StringBuffer hex = new StringBuffer();
for (int i = 0; i < chars.length; i++) {
hex.append(Integer.toHexString((int) chars[i]));
}
String hexText = hex.toString();
System.out.println("Hex Text  = " + hexText);
String decodedText = HexToString(hexText);
System.out.println("Decoded Text = "+decodedText);
} catch (Exception e){
e.printStackTrace();
}
}


public static String HexToString(String hex){


StringBuilder finalString = new StringBuilder();
StringBuilder tempString = new StringBuilder();


for( int i=0; i<hex.length()-1; i+=2 ){
String output = hex.substring(i, (i + 2));
int decimal = Integer.parseInt(output, 16);
finalString.append((char)decimal);
tempString.append(decimal);
}
return finalString.toString();
}

产出如下:

Clear Text = testString For;0181;with.love

十六进制文本 = 74657374537472696e6720466f723b303138313b776974682e6c6f7665

解码文本 = testString For; 0181; with.love

小开

使用来自多线程的多人帮助. 。

我知道这已经得到了回答，但我想给出一个完整的编码和解码方法的任何其他在我同样的情况。.

这是我的编码和解码方法. 。

// Global Charset Encoding
public static Charset encodingType = StandardCharsets.UTF_8;


// Text To Hex
public static String textToHex(String text)
{
byte[] buf = null;
buf = text.getBytes(encodingType);
char[] HEX_CHARS = "0123456789abcdef".toCharArray();
char[] chars = new char[2 * buf.length];
for (int i = 0; i < buf.length; ++i)
{
chars[2 * i] = HEX_CHARS[(buf[i] & 0xF0) >>> 4];
chars[2 * i + 1] = HEX_CHARS[buf[i] & 0x0F];
}
return new String(chars);
}


// Hex To Text
public static String hexToText(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));
}
String st = new String(data, encodingType);
return st;
}
小开

没有外部库的一行 HEX 编码/解码(Java8及以上版本) :

编码:

String hexString = inputString.chars().mapToObj(c ->
Integer.toHexString(c)).collect(Collectors.joining());

译码:

String decodedString = Stream.iterate(0, i -> i+2)
.limit(hexString.length()/2 + Math.min(hexString.length()%2,1))
.map(i -> "" + (char)Integer.parseInt("" + hexString.charAt(i) + hexString.charAt(i+1),16))
.collect(Collectors.joining());
小开

Java17 为十六进制格式引入了一个实用类: < strong > Java.util.HexFormat

转换为十六进制:

public String toHex(String value) {
return HexFormat.of().formatHex(value.getBytes());
}

从十六进制转换:

public String fromHex(String value) {
return new String(HexFormat.of().parseHex(value));
}

More about HexFormat 给你

文件: here


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