What's new in Java 12: How to use the new String API for string comparison

Java is a powerful and widely used programming language, and its versions are constantly updated to provide better functionality and performance. Java 12 is one of the latest versions of Java, which introduces many interesting new features. One of the important new features is the new String API, which provides a more concise and easy-to-use way to handle string comparisons. This article will explain how to use the new String API in Java 12 for string comparison.

In previous Java versions, we usually used the equals() method to compare whether two strings are equal. However, this approach is sometimes clumsy and error-prone. The new String API was introduced in Java 12, which contains some convenient methods for string comparison.

First, let's look at a simple example that shows how to use the new String API to compare two strings for equality:

String str1 = "Hello";
String str2 = "hello";

if (str1.equalsIgnoreCase(str2)) {
    System.out.println("两个字符串相等");
} else {
    System.out.println("两个字符串不相等");
}

In this example, we use equalsIgnoreCase() Method to compare two strings for equality. This method ignores the case of the string, so in this example, even though "Hello" and "hello" have different case, the final returned results are equal. This greatly simplifies the string comparison process.

In addition to the equalsIgnoreCase() method, the String API in Java 12 also provides a more intuitive way to compare strings, which is to use the new compareToIgnoreCase() method. This method compares two strings based on their alphabetical order and ignores case. Here is an example:

String str1 = "apple";
String str2 = "banana";

int result = str1.compareToIgnoreCase(str2);

if (result < 0) {
    System.out.println(str1 + " 在 " + str2 + " 之前");
} else if (result > 0) {
    System.out.println(str1 + " 在 " + str2 + " 之后");
} else {
    System.out.println(str1 + " 和 " + str2 + " 相等");
}

In this example, we compare "apple" and "banana" using the compareToIgnoreCase() method. If the returned result is less than 0, it means str1 is before str2; if the returned result is greater than 0, it means str1 is after str2; if the returned result is equal to 0, it means str1 and str2 are equal.

Another useful new feature is the startsWith() and endsWith() methods. These two methods are used to check whether a string starts or ends with a specified substring. Here is an example:

String str = "Hello, world!";

if (str.startsWith("Hello")) {
    System.out.println("字符串以 'Hello' 开头");
}

if (str.endsWith("world!")) {
    System.out.println("字符串以 'world!' 结尾");
}

In this example, we use the startsWith() and endsWith() methods to check whether a string starts or ends with a specified substring. If the return value is true, it means that the condition is met; if the return value is false, it means that the condition is not met.

In addition to the methods mentioned above, the String API in Java 12 also provides many other practical methods to handle strings. For example, the strip() method is used to remove spaces at both ends of a string; the stripLeading() method is used to remove spaces at the beginning of a string; and the stripTrailing() method is used to remove spaces at the end of a string. In addition, Java 12 also introduces the indent() method, transform() method, etc. These methods can greatly simplify string processing.

To sum up, the new String API in Java 12 provides us with a more concise and easy-to-use way to handle string comparisons. Whether it's ignoring case comparisons, comparing the alphabetical order of strings, or checking whether a string starts or ends with a certain substring, these new methods make our code clearer and more readable. By using these new features, we can handle string comparisons more efficiently, reduce errors, and improve code maintainability.

I hope the content of this article can help you understand the new String API in Java 12 and how to use it for string comparison. By taking full advantage of the new String API, we can write cleaner, more readable code and improve development efficiency.

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