Java中的十进制到十六进制转换器

时间：2012-11-20 01:01:22

标签： java hex decimal converter

我有一个家庭作业，我需要在十进制，二进制和十六进制之间进行三向转换。我需要帮助的函数是将十进制转换为十六进制。我几乎不了解十六进制，但仍然如何将十进制转换为十六进制。我需要一个接收int dec并返回String hex的函数。不幸的是我没有这个功能的任何草稿，我完全迷失了。我只有这个。

  public static String decToHex(int dec)
  {
    String hex = "";


    return hex;
  }

此外，我不能使用像Integer.toHexString（）或其他任何东西的预制函数，我需要实际制作算法，否则我就不会学到任何东西。

12 个答案:

答案 0 :(得分：34)

一种可能的解决方案：

import java.lang.StringBuilder;

class Test {
  private static final int sizeOfIntInHalfBytes = 8;
  private static final int numberOfBitsInAHalfByte = 4;
  private static final int halfByte = 0x0F;
  private static final char[] hexDigits = { 
    '0', '1', '2', '3', '4', '5', '6', '7', 
    '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
  };

  public static String decToHex(int dec) {
    StringBuilder hexBuilder = new StringBuilder(sizeOfIntInHalfBytes);
    hexBuilder.setLength(sizeOfIntInHalfBytes);
    for (int i = sizeOfIntInHalfBytes - 1; i >= 0; --i)
    {
      int j = dec & halfByte;
      hexBuilder.setCharAt(i, hexDigits[j]);
      dec >>= numberOfBitsInAHalfByte;
    }
    return hexBuilder.toString(); 
  }

  public static void main(String[] args) {
     int dec = 305445566;
     String hex = decToHex(dec);
     System.out.println(hex);       
  }
}

输出：

1234BABE

无论如何，有一个库方法：

String hex = Integer.toHexString(dec);

答案 1 :(得分：12)

  

我需要一个接受int dec并返回String hex的函数。

我找到了更优雅的解决方案 http://introcs.cs.princeton.edu/java/31datatype/Hex2Decimal.java.html。我从原来改变了一点（见编辑）

// precondition:  d is a nonnegative integer
public static String decimal2hex(int d) {
    String digits = "0123456789ABCDEF";
    if (d <= 0) return "0";
    int base = 16;   // flexible to change in any base under 16
    String hex = "";
    while (d > 0) {
        int digit = d % base;              // rightmost digit
        hex = digits.charAt(digit) + hex;  // string concatenation
        d = d / base;
    }
    return hex;
}

免责声明：我在编码面试中使用此算法。我希望这个解决方案不会太受欢迎：）

编辑2016年6月17日：我添加了base变量，以便灵活地更改为任何基数：二进制，八进制，7的基数...
根据评论，这个解决方案是最优雅的，所以我删除了Integer.toHexString()的实现。

编辑2015年9月4日：我找到了更优雅的解决方案http://introcs.cs.princeton.edu/java/31datatype/Hex2Decimal.java.html

答案 2 :(得分：2)

考虑将dec2m方法从dec转换为hex，oct或bin。

示例输出

28 dec == 11100 bin 28 dec == 34 oct 28 dec == 1C hex 

public class Conversion {
    public static void main(String[] argv) {
        int x = 28;                           // sample number
        if (argv.length > 0)
            x = Integer.parseInt(argv[0]);    // number from command line

        System.out.printf("%d dec == %s bin\n", i, dec2m(x, 2));
        System.out.printf("%d dec == %s oct\n", i, dec2m(x, 8));
        System.out.printf("%d dec == %s hex\n", i, dec2m(x, 16));
    }

    static String dec2m(int N, int m) {
        String s = "";
        for (int n = N; n > 0; n /= m) {
            int r = n % m;
            s = r < 10 ? r + s : (char) ('A' - 10 + r) + s;
        }
        return s;
    }
}

答案 3 :(得分：1)

另一种可能的解决方案：

public String DecToHex(int dec){
  char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
              'A', 'B', 'C', 'D', 'E', 'F'};
  String hex = "";
  while (dec != 0) {
      int rem = dec % 16;
      hex = hexDigits[rem] + hex;
      dec = dec / 16;
  }
  return hex;
}

答案 4 :(得分：0)

以下是任何数字的代码：

import java.math.BigInteger;

public class Testing {

/**
 * @param args
 */
static String arr[] ={"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"}; 
public static void main(String[] args) {
    String value = "214";
    System.out.println(value + " : " + getHex(value));
}


public static String getHex(String value) {
    String output= "";
    try {
        Integer.parseInt(value);
        Integer number = new Integer(value);
        while(number >= 16){
            output = arr[number%16] + output;
            number = number/16;
        }
        output = arr[number]+output;

    } catch (Exception e) {
        BigInteger number = null;
        try{
            number = new BigInteger(value);
        }catch (Exception e1) {
            return "Not a valid numebr";
        }
        BigInteger hex = new BigInteger("16");
        BigInteger[] val = {};

        while(number.compareTo(hex) == 1 || number.compareTo(hex) == 0){
            val = number.divideAndRemainder(hex);
            output = arr[val[1].intValue()] + output;
            number = val[0];
        }
        output = arr[number.intValue()] + output;
    }

    return output;
}

}

答案 5 :(得分：0)

我会用

Long a = Long.parseLong(cadenaFinal, 16 );

因为有一些十六进制可能比整数更大，它会引发异常

答案 6 :(得分：0)

这是我的

public static String dec2Hex(int num)
{
    String hex = "";

    while (num != 0)
    {
        if (num % 16 < 10)
            hex = Integer.toString(num % 16) + hex;
        else
            hex = (char)((num % 16)+55) + hex;
        num = num / 16;
    }

    return hex;
}

答案 7 :(得分：0)

将Decimal转换为HexaDecimal的更好解决方案，这个更简单

import java.util.Scanner;
public class DecimalToHexa
{
    public static void main(String ar[])
    {
        Scanner sc=new Scanner(System.in);
        System.out.println("Enter a Decimal number: ");
        int n=sc.nextInt();
        if(n<0)
        {
            System.out.println("Enter a positive integer");
            return;
        }
        int i=0,d=0;
        String hx="",h="";
        while(n>0)
        {
            d=n%16;`enter code here`
            n/=16;
            if(d==10)h="A";
            else if(d==11)h="B";
            else if(d==12)h="C";
            else if(d==13)h="D";
            else if(d==14)h="E";
            else if(d==15)h="F";
            else h=""+d;            
            hx=""+h+hx;
        }
        System.out.println("Equivalent HEXA: "+hx);
    }
}

答案 8 :(得分：0)

查看下面的代码，了解十进制到十六进制的转换，

import java.util.Scanner;

public class DecimalToHexadecimal
{
   public static void main(String[] args)
   {
      int temp, decimalNumber;
      String hexaDecimal = "";
      char hexa[] = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};

      Scanner sc = new Scanner(System.in);
      System.out.print("Please enter decimal number : ");
      decimalNumber = sc.nextInt();

      while(decimalNumber > 0)
      {
         temp = decimalNumber % 16;
         hexaDecimal = hexa[temp] + hexaDecimal;
         decimalNumber = decimalNumber / 16;
      }

      System.out.print("The hexadecimal value of " + decimalNumber + " is : " + hexaDecimal);      
      sc.close();
   }
}

您可以在以下链接中了解有关将十进制转换为十六进制的不同方法的更多信息＆gt;＆gt; java convert decimal to hexadecimal

答案 9 :(得分：0)

以下将十进制转换为Hexa Decimal 时间复杂度：O（n）线性时间没有任何java内置函数

private static String decimalToHexaDecimal(int N) {
    char hexaDecimals[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
    StringBuilder builder = new StringBuilder();
    int base= 16;
    while (N != 0) {
        int reminder = N % base;
        builder.append(hexaDecimals[reminder]);
        N = N / base;
    }

    return builder.reverse().toString();
}

答案 10 :(得分：0)

最简单的方法是：

String hexadecimalString = String.format("%x", integerValue);

答案 11 :(得分：-1)

转换DECIMAL-to-＆gt;的代码二进制，十月，十六，

public class ConvertBase10ToBaseX {
    enum Base {
        /**
         * Integer is represented in 32 bit in 32/64 bit machine.
         * There we can split this integer no of bits into multiples of 1,2,4,8,16 bits
         */
        BASE2(1,1,32), BASE4(3,2,16), BASE8(7,3,11)/* OCTAL*/, /*BASE10(3,2),*/ 
        BASE16(15, 4, 8){       
            public String getFormattedValue(int val){
                switch(val) {
                case 10:
                    return "A";
                case 11:
                    return "B";
                case 12:
                    return "C";
                case 13:
                    return "D";
                case 14:
                    return "E";
                case 15:
                    return "F";
                default:
                    return "" + val;
                }

            }
        }, /*BASE32(31,5,1),*/ BASE256(255, 8, 4), /*BASE512(511,9),*/ Base65536(65535, 16, 2);

        private int LEVEL_0_MASK;
        private int LEVEL_1_ROTATION;
        private int MAX_ROTATION;

        Base(int levelZeroMask, int levelOneRotation, int maxPossibleRotation) {
            this.LEVEL_0_MASK = levelZeroMask;
            this.LEVEL_1_ROTATION = levelOneRotation;
            this.MAX_ROTATION = maxPossibleRotation;
        }

        int getLevelZeroMask(){
            return LEVEL_0_MASK;
        }
        int getLevelOneRotation(){
            return LEVEL_1_ROTATION;
        }
        int getMaxRotation(){
            return MAX_ROTATION;
        }
        String getFormattedValue(int val){
            return "" + val;
        }
    }

    public void getBaseXValueOn(Base base, int on) {
        forwardPrint(base, on);
    }

    private void forwardPrint(Base base, int on) {

        int rotation = base.getLevelOneRotation();
        int mask = base.getLevelZeroMask();
        int maxRotation = base.getMaxRotation();
        boolean valueFound = false;

        for(int level = maxRotation; level >= 2; level--) {
            int rotation1 = (level-1) * rotation;
            int mask1 = mask << rotation1 ;
            if((on & mask1) > 0 ) {
                valueFound = true;
            }
            if(valueFound)
            System.out.print(base.getFormattedValue((on & mask1) >>> rotation1));
        }
        System.out.println(base.getFormattedValue((on & mask)));
    }

    public int getBaseXValueOnAtLevel(Base base, int on, int level) {
        if(level > base.getMaxRotation() || level < 1) {
            return 0; //INVALID Input
        }
        int rotation = base.getLevelOneRotation();
        int mask = base.getLevelZeroMask();

        if(level > 1) {
            rotation = (level-1) * rotation;
            mask = mask << rotation;
        } else {
            rotation = 0;
        }


        return (on & mask) >>> rotation;
    }

    public static void main(String[] args) {
        ConvertBase10ToBaseX obj = new ConvertBase10ToBaseX();

        obj.getBaseXValueOn(Base.BASE16,12456); 
//      obj.getBaseXValueOn(Base.BASE16,300); 
//      obj.getBaseXValueOn(Base.BASE16,7); 
//      obj.getBaseXValueOn(Base.BASE16,7);

        obj.getBaseXValueOn(Base.BASE2,12456);
        obj.getBaseXValueOn(Base.BASE8,12456);
        obj.getBaseXValueOn(Base.BASE2,8);
        obj.getBaseXValueOn(Base.BASE2,9);
        obj.getBaseXValueOn(Base.BASE2,10);
        obj.getBaseXValueOn(Base.BASE2,11);
        obj.getBaseXValueOn(Base.BASE2,12);
        obj.getBaseXValueOn(Base.BASE2,13);
        obj.getBaseXValueOn(Base.BASE2,14);
        obj.getBaseXValueOn(Base.BASE2,15);
        obj.getBaseXValueOn(Base.BASE2,16);
        obj.getBaseXValueOn(Base.BASE2,17);


        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 1)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 2)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 3)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 4)); 

        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,15, 1)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,30, 2)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,7, 1)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,7, 2)); 

        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 511, 1)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 511, 2)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 512, 1));
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 512, 2)); 
        System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 513, 2)); 


    }
}
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