Singleton mode is used to ensure that a class has only one instance during the run of the program. The advantage is to solve system resources as much as possible. Singleton mode can be implemented by modifying the access permissions of the constructor.
The code is as follows:
The code copy is as follows:
public class Emperor {
private static Emperor = null;// Declare a reference to the Emperor class
private Emperor() {// Private constructor
}
public static Emperor getInstance() {// Instantiate the reference
if (emperor == null) {
emperor = new Emperor();
}
return emperor;
}
public void getName() {// Use ordinary method to output the emperor's name
System.out.println("I am the emperor: Tomorrow Technology");
}
}
public class Test {
public static void main(String[] args) {
System.out.println("Create Emperor 1 object:");
Emperor emperor1 = Emperor.getInstance();// Create an emperor object
emperor1.getName();// Export the emperor's name
System.out.println("Create Emperor 2 object:");
Emperor emperor2 = Emperor.getInstance();// Create an emperor object
emperor2.getName();// Export the emperor's name
System.out.println("Create Emperor 3 object:");
Emperor emperor3 = Emperor.getInstance();// Create an emperor object
emperor3.getName();// Export the emperor's name
}
}
The effect is shown in the picture: