Learn Java 12th Day Personal summary

Day12 Personal Summary

First, design mode:

1 , Singleton mode Advantages: 1) Save memory 2) Avoid State conflicts due to multiple states The singleton model is divided into lazy mode and bad-han mode. 2 , a hungry man mode 1) Privatization Construction method 2) Create an instance in this class 3) The instance needs to be privatized private, to ensure that the instance can only be assigned once, using the modifier final to modify 4) provide a get to allow the outside world to use this instance 5) The method requires a static The code format is as follows: 6) Hungryinstance Class Main method: 3 , lazy mode 1) Privatization Construction method 2) Properties of the privatization statement 3) getinstance Determines whether the property is empty if NULL creates an object that is not empty directly returns an object 4) method requires static The code is as follows: INSTANCE New in the Mian method: The biggest difference between the A hungry man and the lazy type is that A hungry man-type, more secure

Second, the factory model

1 , Factory mode 1) is a factory-class approach with production products 2) is the parent of the production product 3) A variety of products, such as 2 , key details The subclass of the factory pattern needs to inherit the product's parent class, and the type of the factory method return value is the parent class type of the product, but the object of the product subclass is actually put back, and the factory method needs to have parameters in order to determine the production of that super- 3 , the role of the factory model: 1) Mass production 2) Production of diversified products

Learn Java 12th Day Personal summary