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：
1. 提交源代码；
//Account.java
package shiyan22;
/**
* @Description：环境类
* @author 张紫诺
*
*/
public class Account {
private AccountState state;
private String name;
public Account(String name){
this.name=name;
state=new Greenstate(this);
System.out.println(name+"开户成功！初始金额：0元");
System.out.println("******************************");
}
public void setState(AccountState state){
this.state=state;
}
public AccountState getState() {
return this.state;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void deposit(double money){
state.deposit(money);
}
public void withdraw(double money){
state.withdraw(money);
}
}
//AccountState.java
package shiyan22;
/**
* @Description：抽象状态类
* @author 张紫诺
*
*/
public abstract class AccountState {
protected Account acc;
protected double balance;
protected String stateName;
public abstract void stateCheck(double balance);
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public String getStateName() {
return stateName;
}
public void setStateName(String stateName) {
this.stateName = stateName;
}
public void deposit(double amount) {
System.out.println(acc.getName()+"存款"+amount+"元");
balance+=amount;
stateCheck(balance);
System.out.println("当前余额："+balance+"元，当前状态："+acc.getState().stateName);
}
public void withdraw(double amount) {
System.out.println(acc.getName()+"取款"+amount+"元");
balance-=amount;
stateCheck(balance);
System.out.println("当前余额："+balance+"元，当前状态："+acc.getState().stateName);
}
}
//Greenstate.java
package shiyan22;
/**
* @Description：正常状态类
* @author 张紫诺
*
*/
public class Greenstate extends AccountState{
public Greenstate(AccountState state){
this.acc=state.acc;
this.balance=state.balance;
this.stateName="正常状态";
}
public Greenstate(Account acc){
this.balance=0;
this.acc=acc;
this.stateName="正常状态";
}
public void stateCheck(double balance){
if(balance<-1000){
acc.setState(new Redstate(this));
}else if(balance>=-1000&&balance<0){
acc.setState(new Yellowstate(this));
}
}
}
//Redstate.java
package shiyan22;
/**
* @Description：透支状态类
* @author 张紫诺
*
*/
public class Redstate extends AccountState {
public Redstate(AccountState state) {
this.acc=state.acc;
this.balance=state.getBalance();
this.stateName="透支状态";
}
public void stateCheck(double balance) {
if(balance >= -1000 && balance < 0){
acc.setState(new Yellowstate(this));
}else if(balance >= 0){
acc.setState(new Greenstate(this));
}
}
public void withdraw(double amount) {
System.out.println("对不起，"+acc.getName()+",您不能取款");
System.out.println("当前余额："+balance+"元，当前状态："+acc.getState().stateName);
}
}
//Yellowstate.java
package shiyan22;
/**
* @Description：欠费状态类
* @author 张紫诺
*
*/
public class Yellowstate extends AccountState {
public Yellowstate(AccountState state) {
this.acc=state.acc;
this.balance=state.getBalance();
this.stateName="欠费状态";
}
public void stateCheck(double balance) {
if(balance >=0 ){
acc.setState(new Greenstate(this));
}else if(balance < -1000){
acc.setState(new Redstate(this));
}
}
}
//Client.java
package shiyan22;
public class Client {
public static void main(String args[]){
Account acc=new Account("张三");
acc.deposit(2000);
System.out.println("---------------------------------------");
acc.withdraw(500);
System.out.println("---------------------------------------");
acc.withdraw(2000);
System.out.println("---------------------------------------");
acc.withdraw(600);
System.out.println("---------------------------------------");
acc.withdraw(200);
}
}
