23种设计模式(九)桥接模式

以你之姓@ 2022-12-30 08:25 26阅读 0赞

## 桥接模式 ##

> 一般问题：一个类需要在两个以上维度扩展，采用继承方式会导致子类数量过多
> 
> 核心方案：将抽象部分与实现部分分离，使其都可以独立变化

银行，我有活期账户，定期账户，不同的银行，打开账户

public interface Account { 
        Account openAccount();
        void showAccountType();
    }

public abstract class Bank { 
        protected Account account;
        public Bank(Account account){ 
            this.account = account;
        }
        abstract Account openAccount();
    
    }

public class ABCBank extends Bank { 
        public ABCBank(Account account) { 
            super(account);
        }
    
        @Override
        Account openAccount() { 
            System.out.println("打开中国农业银行账号");
            account.openAccount();
            return account;
        }
    }

public class ICBCBank extends Bank { 
        public ICBCBank(Account account) { 
            super(account);
        }
    
        @Override
        Account openAccount() { 
            System.out.println("打开中国工商银行账号");
            account.openAccount();
            return account;
        }
    }

public class DepositAccount implements Account { 
        @Override
        public Account openAccount() { 
            System.out.println("打开定期账号");
            return new DepositAccount();
        }
    
        @Override
        public void showAccountType() { 
            System.out.println("这是一个定期账号");
        }
    }

public class SavingAccount implements Account { 
        @Override
        public Account openAccount() { 
            System.out.println("打开活期账号");
            //...
            return new SavingAccount();
        }
    
        @Override
        public void showAccountType() { 
            System.out.println("这是一个活期账号");
        }
    }

Bank icbcBank = new ICBCBank(new DepositAccount());
            Account icbcAccount = icbcBank.openAccount();
            icbcAccount.showAccountType();
    
            Bank icbcBank2 = new ICBCBank(new SavingAccount());
            Account icbcAccount2 = icbcBank2.openAccount();
            icbcAccount2.showAccountType();
    
            Bank abcBank = new ABCBank(new SavingAccount());
            Account abcAccount = abcBank.openAccount();
            abcAccount.showAccountType();