编写一个程序，创建一个 HashMap对象，用于存储银行储户的信息(其中储户的主要信息有储户的ID，姓名和余额)。另外，计算并显示其中某个储户的当前余额。

package javademo12;

public class Customer {
   
   
	private int ID;
	public Customer() {
   
   
		super();
		// TODO Auto-generated constructor stub
	}
	public Customer(int iD, String name, double balance) {
   
   
		super();
		ID = iD;
		this.name = name;
		this.balance = balance;
	}
	@Override
	public String toString() {
   
   
		return "Customer [ID=" + ID + ", name=" + name + ", balance=" + balance + "]";
	}
	@Override
	public int hashCode() {
   
   
		final int prime = 31;
		int result