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。
（1）Account.java：
package shiyan22;
/**
* @Description：环境类
* @author 马荣荣
*
*/
public class Account {
private AccountState state;
private String owner;
public Account(String a,double b){
owner=a;
state=new Yellowstate(this,b);
state.stateCheck();
}
public void setsta(AccountState a){
state=a;
}
public void deposit(double a){
System.out.println(owner+"存"+a+"元");
state.deposit(a);
state.stateCheck();
System.out.println();
}
public void withdraw(double a){
System.out.println(owner+"取"+a+"元");
state.withdraw(a);
state.stateCheck();
System.out.println();
}
}
（2）AccountState.java：
package shiyan22;
/**
* @Description：抽象状态类
* @author 马荣荣
*
*/
public abstract class AccountState {
protected Account acc;
protected double balance;
public AccountState(Account a,double b){
super();
acc=a;
balance=b;
}
public abstract void stateCheck();
public void deposit(double amount) {
balance+=amount;
System.out.println("存款成功");
System.out.println("余额为"+balance+"元");
}
public void withdraw(double amount) {
if((balance-amount)>-1000) {
System.out.println("取钱成功！");
balance -= amount;
System.out.println("当前余额："+balance+"元");
}else {
System.out.println("余额不足！");
System.out.println("当前余额："+balance+"元");
}
}
}
（3）Client.java：
package shiyan22;
public class Client {
public static void main(String args[]){
Account acc=new Account("账户20194021",200);
acc.deposit(3000);
acc.withdraw(1000);
acc.withdraw(3500);
}
}
（4）Greenstate.java：
package shiyan22;
/**
* @Description：正常状态类
* @author 马荣荣
*
*/
public class Greenstate extends AccountState{
public Greenstate(Account a,double b){
super(a,b);
}
public void stateCheck(){
if(balance<-1000){
acc.setsta(new Redstate(acc,balance));
}else if(balance>=-1000&&balance<0){
acc.setsta(new Yellowstate(acc,balance));
}
}
}
（5）Redstate.java：
package shiyan22;
/**
* @Description：透支状态类
* @author 马荣荣
*
*/
public class Redstate extends AccountState {
public Redstate(Account acc, double balance) {
super(acc, balance);
}
public void stateCheck() {
if(balance >= -1000 && balance < 0){
acc.setsta(new Yellowstate(acc, balance));
}else if(balance >= 0){
acc.setsta(new Greenstate(acc,balance));
}
}
public void withdraw(double amount) {
System.out.println("余额不足！");
System.out.println("当前余额："+balance);
}
}
（6）Yellowstate.java：
package shiyan22;
/**
* @Description：欠费状态类
* @author 马荣荣
*
*/
public class Yellowstate extends AccountState {
public Yellowstate(Account acc, double balance) {
super(acc, balance);
}
public void stateCheck() {
if(balance >=0 ){
acc.setsta(new Greenstate(acc,balance));
}else if(balance < -1000){
acc.setsta(new Redstate(acc,balance));
}
}
}
实现截图：