10.30每日总结

软件设计                  石家庄铁道大学信息学院

 

实验 22：状态模式

本次实验属于模仿型实验，通过本次实验学生将掌握以下内容： 

1、理解状态模式的动机，掌握该模式的结构；

2、能够利用状态模式解决实际问题。

 

[实验任务一]：银行账户

用Java代码模拟实现课堂上的“银行账户”的实例，要求编写客户端测试代码模拟用户存款和取款，注意账户对象状态和行为的变化。

实验要求：

package twenty_two;

 

public class Client {

 

    public static void main(String[] args) {

        Account account = new Account("张三",100);

        account.deposit(8888);

        System.out.println("------------------------------");

        account.withdraw(666);

        System.out.println("------------------------------");

        account.deposit(50);

        System.out.println("------------------------------");

        account.withdraw(9000);

        System.out.println("------------------------------");

        account.withdraw(50000);

        System.out.println("------------------------------");

        account.deposit(3000);

        System.out.println("------------------------------");

        account.withdraw(100);

    }

}

package twenty_two;

 

public class Account {

    private AccountState state;

    private String owner;

 

    public AccountState getState() {

        return state;

    }

 

    public void setState(AccountState state) {

        this.state = state;

    }

 

    public String getOwner() {

        return owner;

    }

 

    public void deposit(double amount) {

        state.deposit(amount);

    }

 

    public void withdraw(double amount) {

        state.withdraw(amount);

    }

 

    public Account(String owner, double initBalance) {

        this.owner = owner;

        this.state = new GreenState(initBalance,this);

        System.out.println(this.owner + "开户成功！银行卡初始金额：" + initBalance);

        System.out.println("----------------------------------------------------");

    }

}

package twenty_two;

 

public abstract class AccountState {

    protected Account account;//账户名

    protected double balance;//账户金额

    protected String stateName;//当前状态

 

    public void deposit(double amount) {

        System.out.println(account.getOwner() + "存款" + amount);

        this.balance = this.balance + amount;

        stateCheck();

        System.out.println("账户余额：" + this.balance);

        System.out.println("账户状态：" + account.getState().stateName);

    }

 

    public void withdraw(double amount) {

        System.out.println(account.getOwner() + "取款" + amount);

        this.balance = this.balance - amount;

        stateCheck();

        System.out.println("账户余额：" + this.balance);

        System.out.println("账户状态：" + account.getState().stateName);

    }

 

    public void stateCheck(){//状态审查

        if( balance >= -1000 && balance < 0 ) {

            account.setState(new YellowState(this));

        }else if( balance < -1000 ) {

            account.setState(new RedState(this));

        }else if ( balance > 0 ){

            account.setState(new GreenState(this.balance,this.account));

        }

    }

}

package twenty_two;

 

public class GreenState extends AccountState{

 

    public GreenState(double balance,Account acc) {

        this.balance = balance;

        this.account = acc;

        this.stateName = "正常状态";

    }

}

package twenty_two;

 

public class RedState extends AccountState{

 

    public RedState(AccountState state) {

        this.balance = state.balance;

        this.account = state.account;

        this.stateName="透支状态";

    }

 

    public void withdraw(double amount) {

        System.out.println(account.getOwner()+"取款"+amount);

        System.out.println("抱歉，您的账户已处于透支状态，不能取款！");

    }

}

package twenty_two;

 

public class YellowState extends AccountState{

 

    public YellowState(AccountState state) {

        this.balance = state.balance;

        this.account = state.account;

        this.stateName="欠费状态";

    }

}