PractiseCode 设计模式包:com.wenbin.design.mode 简单工厂: com.wenbin.design.mode.factory.TestFactory 策略模式: com.wenbin.design.mode.strategy.operation.OperationContext 简单工厂+策略: com.wenbin.design.mode.strategy.operation.OperationAndFactoryContext 使用简单工厂+策略模式,解决实际工作中不同的供应商的债权生成账单的算法不一样:com.wenbin.design.mode.strategy.bill.CalculateBillContext