How to get the length of a string using the length() function of the StringBuilder class in Java

How does Java use the length() function of the StringBuilder class to get the length of a string

In Java, we often need to get the length of a string to perform various operations, such as determining whether the string is empty, Count the number of characters in a string, etc. Java provides a convenient way to get the length of a string, using the length() function of the StringBuilder class. This article will explain how to use the length() function of the StringBuilder class to obtain the length of a string, and provide corresponding code examples for reference.

First, we need to understand the StringBuilder class. StringBuilder is a variable string class in Java. It provides many methods for manipulating strings, such as concatenating strings, inserting strings, deleting strings, etc. Unlike the String class, StringBuilder is not an immutable class, so its length can be changed.

Use the length() function of the StringBuilder class to get the length of the current string. This length refers to the number of characters in the string, not the number of bytes. The length() function returns an integer representing the length of the string.

Next, let’s take a look at a code example that uses the length() function of the StringBuilder class to obtain the length of a string:

public class StringLengthExample {
    public static void main(String[] args) {
        StringBuilder strBuilder = new StringBuilder("Hello, World!");
        
        int length = strBuilder.length();
        System.out.println("字符串的长度是：" + length);
    }
}

In the above code, we create a StringBuilder object strBuilder and initialize it For the string "Hello, World!". Then, we use strBuilder's length() function to get the length of the string and assign the result to the variable length. Finally, we use the System.out.println() function to output the length of the string to the console.

Run the above code, the output result is:

字符串的长度是：13

It can be seen from the result that the length of the string "Hello, World!" is indeed 13.

It should be noted that the length() function returns the length of the string, not the length of the subscript. In Java, string subscripts start from 0, so the length of a string is equal to the subscript of the last character in the string plus 1. For example, if the length of a string is 10, then its last character is indexed to 9.

In addition, it should be noted that if you are using the String class instead of the StringBuilder class, you can use the length() function of the String class to obtain the length of the string. The usage method is the same as the length() of the StringBuilder class. The functions are the same.

To sum up, using the length() function of the StringBuilder class can easily obtain the length of a string. Through the introduction and code examples of this article, I believe readers will have a deeper understanding of how to use the length() function of the StringBuilder class to obtain the length of a string. In daily Java development, we can perform various operations based on the length of the string to better process strings.

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