The role of Supplier and its use

Supplier: From the meaning of the word, it can provide (produce) a generic object instance, the source code is as follows:

Demo

public Flux<Apple> getApple(@PathVariable String id) {
   
    
    
    //创建Supplier容器，声明为TestSupplier类型，此时并不会调用对象的构造方法，即不会创建对象
    Supplier<