Usage analysis of Character class
This article mainly introduces the Character class methods in JAVA in detail. Friends who need it can refer to
When using characters, we usually use the built-in data type char.
Example
char ch = 'a';
// Unicode for uppercase Greek omega character
char uniChar = '\u039A';
// 字符数组
char[] charArray ={ 'a', 'b', 'c', 'd', 'e' };However, in the actual development process, we often encounter the need to use objects instead of built-in data type of situation. In order to solve this problem, the Java language provides a wrapper class Character class for the built-in data type char.
The Character class provides a series of methods to manipulate characters. You can use Character's constructor method to create a Character class object, for example:
Character ch = <a href="http://www.php.cn/wiki/165.html" target="_blank">new</a> Character('a');
In some cases, the Java compiler will automatically create a Character object.
For example, when a char type parameter is passed to a method that requires a Character type parameter, the compiler will automatically convert the char type parameter into a Character object. This feature is called boxing, and the converse is called unboxing.
Example
// Here following primitive char 'a' // is boxed into the Character object ch Character ch = 'a'; // Here primitive 'x' is boxed for method test, // return is unboxed to char 'c' char c = test('x');
Escape sequence
The character preceded by a backslash (\) represents an escape character, It has special meaning to the compiler.
The following list shows Java's escape sequences:
| Escape Sequence | Description |
| \t | Insert a tab key at this point in the text |
| \b | At this point in the text Insert a back key |
| \n | and wrap the line in the text |
| \r | Insert a carriage return |
| \f | Insert a page feed |
| \' | Insert single quotation marks in the text |
| Insert double quotation marks in the text | |
| Insert a backslash here in the text |
Example
public class Test {
public static void main(String args[]) {
System.out.println("She said \"Hello!\" to me.");
}
}She said "Hello!" to me.
Character method
| Method and description | |
| isLetter() Is it a letter | |
| isDigit()Is it a numeric character | |
| isWhitespace()Whether it is a space | |
| isUpperCase()Whether it is an uppercase letter | |
| isLowerCase() |
Is it a lowercase letter | ##6
| toUpperCase() | Specify the uppercase form of letters | 7
| toLowerCase() | Specifies the lowercase form of the letter ##8 |
| Returns the | character of the character String form, the length of the string is only 1 | [Related recommendations]
2. Detailed explanation of instances of the Character class
3. Detailed explanation of the differences between Character and char methods
4. Explain in detail the Character class in Java
5. Instance analysis of the packaging class Character
The above is the detailed content of Usage analysis of Character class. For more information, please follow other related articles on the PHP Chinese website!
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