解决来自耦合性、内聚性、可维护性、重用性和灵活性等多方面的问题
不要拘泥于某种模式的套路，许多框架在设计时并不会严格按照某种套路来写，重要的是体会设计模式的思路。
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Copyright (c) 2021 paigeman
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