# Java 程序：十进制到二进制的转换 > 原文： [https://beginnersbook.com/2014/07/java-program-to-convert-decimal-to-binary/](https://beginnersbook.com/2014/07/java-program-to-convert-decimal-to-binary/) 将十进制数转换为二进制数有以下三种方法： 1）使用`Integer`类的[`toBinaryString()`方法](https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html#toBinaryString(int))。 2）通过编写自己的逻辑进行转换，而无需使用任何预定义的方法。 3）使用`Stack` ### 方法 1：使用`toBinaryString()`方法 ```java class DecimalBinaryExample{ public static void main(String a[]){ System.out.println("Binary representation of 124: "); System.out.println(Integer.toBinaryString(124)); System.out.println("\nBinary representation of 45: "); System.out.println(Integer.toBinaryString(45)); System.out.println("\nBinary representation of 999: "); System.out.println(Integer.toBinaryString(999)); } } ``` **输出：** ```java Binary representation of 124: 1111100 Binary representation of 45: 101101 Binary representation of 999: 1111100111 ``` ### 方法 2：不使用预定义的方法 ```java class DecimalBinaryExample{ public void convertBinary(int num){ int binary[] = new int[40]; int index = 0; while(num > 0){ binary[index++] = num%2; num = num/2; } for(int i = index-1;i >= 0;i--){ System.out.print(binary[i]); } } public static void main(String a[]){ DecimalBinaryExample obj = new DecimalBinaryExample(); System.out.println("Binary representation of 124: "); obj.convertBinary(124); System.out.println("\nBinary representation of 45: "); obj.convertBinary(45); System.out.println("\nBinary representation of 999: "); obj.convertBinary(999); } } ``` **输出：** ```java Binary representation of 124: 1111100 Binary representation of 45: 101101 Binary representation of 999: 1111100111 ``` ### 方法 3：使用`Stack`进行二进制到十进制转换 ```java import java.util.*; class DecimalBinaryStack { public static void main(String[] args) { Scanner in = new Scanner(System.in); // Create Stack object Stack<Integer> stack = new Stack<Integer>(); // User input System.out.println("Enter decimal number: "); int num = in.nextInt(); while (num != 0) { int d = num % 2; stack.push(d); num /= 2; } System.out.print("\nBinary representation is:"); while (!(stack.isEmpty() )) { System.out.print(stack.pop()); } System.out.println(); } } ``` **输出：** ```java Enter decimal number: 999 Binary representation is:1111100111 ```