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

Java is a programming language widely used in software development. New versions are released every once in a while, which contain some new features and improvements. Java 12 is the latest version released in 2019 and brings many exciting new features. This article will focus on a new feature in Java 12, the new String API, and how to use it for string operations.

In the traditional Java version, string operations require the use of methods of the String class, such as charAt(), length(), substring()And so on. These methods, while powerful, can be a bit tedious when working with strings. Java 12 simplifies the process of string manipulation by introducing a new set of string methods.

Let us first look at a simple example to illustrate how to use the new String API for string concatenation operations.

String str1 = "Hello";
String str2 = "World";
String str3 = str1 + str2;
System.out.println(str3);

In the above example, we use the operator to concatenate two strings. This is a common way, but has some performance issues in Java. Strings in Java are immutable. Each splicing operation will produce a new string object, and the original string object will be discarded. This results in performance loss.

The new String API in Java 12 provides a more efficient way to join strings, using the String.join() method. Let's look at a specific example.

String str1 = "Hello";
String str2 = "World";
String str3 = String.join(" ", str1, str2);
System.out.println(str3);

In the above example, we use the String.join() method to concatenate two strings using spaces as the separator. This method does not generate a new string object, but directly operates the original string, which improves performance.

In addition to string concatenation, the new String API in Java 12 also provides some other useful methods. Let's take a look at some examples.

• String.repeat(int count): Repeat the string count times.

String str = "Hello";
String repeatedStr = str.repeat(3);
System.out.println(repeatedStr);

The above example will print "HelloHelloHello".

• String.lines(): Split the string into lines.

String str = "Hello
World
Java";
Stream<String> lines = str.lines();
lines.forEach(System.out::println);

The above example will print "Hello", "World" and "Java" respectively.

• String.strip(): Removes blank characters at the beginning and end of the string.

String str = "  Hello   ";
String strippedStr = str.strip();
System.out.println(strippedStr);

The above example will print "Hello".

• String.isBlank(): Determine whether the string is blank.

String str1 = "Hello";
String str2 = "  ";
System.out.println(str1.isBlank()); // false
System.out.println(str2.isBlank()); // true

The above example will print out false and true respectively.

As mentioned above, the new String API in Java 12 brings a concise and efficient way to string operations. We can improve the performance and readability of our code by using the new String API. I hope this article helps you understand and use the new features in Java 12.

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