Java中将字符串转换为十六进制
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Converting A String To Hexadecimal In Java
提问by
I am trying to convert a string like "testing123" into hexadecimal form in java. I am currently using BlueJ.
我试图在java中将像“testing123”这样的字符串转换为十六进制形式。我目前正在使用 BlueJ。
And to convert it back, is it the same thing except backward?
并将其转换回来，除了向后之外是同一回事吗？
回答by rodion
I would suggest something like this, where stris your input string:
我会建议这样的东西，str你的输入字符串在哪里：
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());
}
回答by Stephen Denne
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.
您编码为十六进制的数字必须代表字符的某种编码，例如 UTF-8。因此，首先将 String 转换为表示该编码中的字符串的 byte[]，然后将每个字节转换为十六进制。
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);
}
回答by Laurence Gonsalves
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
You could return hexStringat this point, with the caveat that leading null-chars will be stripped, and the result will have an odd length if the first byte is less than 16. If you need to handle those cases, you can add some extra code to pad with 0s:
此时您可以返回hexString，但需要注意的是，前导空字符将被剥离，如果第一个字节小于 16，则结果将具有奇数长度。如果您需要处理这些情况，您可以添加一些额外的代码用 0 填充：
StringBuilder sb = new StringBuilder();
while ((sb.length() + hexString.length()) < (2 * bytes.length)) {
sb.append("0");
}
sb.append(hexString);
return sb.toString();
回答by Kaleb Pederson
Here's a short way to convert it to hex:
这是将其转换为十六进制的简短方法：
public String toHex(String arg) {
return String.format("%040x", new BigInteger(1, arg.getBytes(/*YOUR_CHARSET?*/)));
}
回答by Jos Theeuwen
To ensure that the hex is always 40 characters long, the BigInteger has to be positive:
为确保十六进制始终为 40 个字符长，BigInteger 必须为正数：
public String toHex(String arg) {
return String.format("%x", new BigInteger(1, arg.getBytes(/*YOUR_CHARSET?*/)));
}
回答by Joshua Swink
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
http://commons.apache.org/codec/apidocs/org/apache/commons/codec/binary/Hex.html
回答by jordeu
Here an other solution
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();
}
回答by Dmitriy Bocharov
Much better:
好多了：
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);
}
回答by TouchBoarder
To get the Integer value of hex
获取十六进制的整数值
//hex like: 0xfff7931e to int
int hexInt = Long.decode(hexString).intValue();
回答by Rowena Jimenez
import java.io.*;
import java.util.*;
public class Exer5{
public String ConvertToHexadecimal(int num){
int r;
String bin="##代码##";
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);
}
}
