1. Overview

1.概述

In this tutorial, we’ll look briefly at the different ways of printing an integer in binary format in Java.

在本教程中，我们将简要介绍在Java中以二进制格式打印整数的不同方法。

First, we’ll take a conceptual look. And then, we’ll learn some built-in Java functions for conversion.

首先，我们将从概念上看一下。然后，我们将学习一些用于转换的内置Java函数。

2. Using Integer to Binary Conversion

2.使用整数到二进制的转换

In this section, we’ll write our custom method to convert an integer into a binary format string in Java. Before writing the code, let’s first understand how to convert an integer into a binary format.

在本节中，我们将写出我们的自定义方法，在Java中把一个整数转换成二进制格式的字符串。在写代码之前，让我们先了解一下如何将一个整数转换成二进制格式。

To convert an integer n into its binary format, we need to:

要将一个整数n转换成其二进制格式，我们需要。

Store the remainder when number n is divided by 2 and update the number n with the value of the quotient
Repeat step 1 until the number n is greater than zero
Finally, print the remainders in reverse order

Let’s see an example of converting 7 into its binary format equivalent:

让我们看一个将7转换为二进制格式等价物的例子。

First, divide 7 by 2: remainder 1, quotient 3
Second, divide 3 by 2: remainder 1, quotient 1
Then, divide 1 by 2: remainder 1, quotient 0
And finally, print the remainders in reverse order since the quotient in the previous step is 0: 111

Next, let’s implement the above algorithm:

接下来，我们来实现上述算法。

public static String convertIntegerToBinary(int n) {
    if (n == 0) {
        return "0";
    }
    StringBuilder binaryNumber = new StringBuilder();
    while (n > 0) {
        int remainder = n % 2;
        binaryNumber.append(remainder);
        n /= 2;
    }
    binaryNumber = binaryNumber.reverse();
    return binaryNumber.toString();
}

3. Using Integer#toBinaryString Method

3.使用Integer#toBinaryString方法

Java’s Integer class has a method named toBinaryString to convert an integer into its binary equivalent string.

Java的Integer类有一个名为toBinaryString的方法，将一个整数转换成其二进制等价字符串。

Let’s look at the signature of the Integer#toBinaryString method:

我们来看看Integer#toBinaryString方法的签名。

public static String toBinaryString(int i)

It takes an integer argument and returns a binary string representation of that integer:

它接受一个整数参数并返回该整数的二进制字符串表示。

int n = 7;
String binaryString = Integer.toBinaryString(n);
assertEquals("111", binaryString);

4. Using Integer#toString Method

4.使用Integer#toString方法

Now, let’s look at the signature of the Integer#toString method:

现在，让我们看看Integer#方法的签名。

public static String toString(int i, int radix)

The Integer#toString method is an in-built method in Java that takes two arguments. First, it takes an integer that is to be converted to a string. Second, it takes radix that is to be used while converting the integer into its string representation.

Integer#toString方法是Java中内置的方法，需要两个参数。首先，它接收一个要转换为字符串的整数。其次，它需要在将整数转换为字符串表示时使用的弧度。

It returns a string representation of the integer input in the base specified by the radix.

它返回整数输入的字符串表示，其基数由弧度指定。

Let’s use this method to convert an integer into its binary format using a radix value of 2:

让我们用这个方法将一个整数转换成它的二进制格式，使用2的弧度值。

int n = 7;
String binaryString = Integer.toString(n, 2);
assertEquals("111", binaryString);

As we can see that we passed the radix value of 2 while calling the Integer#toString method to convert the integer n into its binary string representation.

我们可以看到，在调用Integer#toString方法将整数n转换为二进制字符串表示时，我们传递了2的拉德值。

5. Conclusion

5.总结

In conclusion, we looked at integer to binary conversion. Furthermore, we saw a couple of built-in Java methods to convert an integer into a string in binary format.

最后，我们研究了整数到二进制的转换。此外，我们还看到了几个内置的Java方法，将一个整数转换成二进制格式的字符串。

As always, all these code samples are available over on GitHub.

一如既往，所有这些代码样本都可以在GitHub上找到。