一个关于自己定义的类,做为hashMap的key对象的例子

package iss.com.equals;import java.util.Date;class CountIsable { private Date date; private String accountNo; private String bankCode; public CountIsable(Date transactionTime, String accountNo, String bankCode) {  this.date = transactionTime;  this.accountNo = accountNo;  this.bankCode = bankCode; } public CountIsable(String accountNo, String bankCode) {  this.accountNo = accountNo;  this.bankCode = bankCode; }                 public boolean equals(CountIsable mapKey) {  if (DateUtil.compareDate(date, mapKey.getDate()) == 0    && accountNo.equals(mapKey.getAccountNo())) {   if (mapKey.getBankCode() == null     || mapKey.getBankCode().equals(bankCode))    return true;  }  return false; } public boolean equals(Object key) {  CountIsable mapKey=(CountIsable)key;  if (DateUtil.compareDate(date, mapKey.getDate()) == 0    && accountNo.equals(mapKey.getAccountNo())) {   if (mapKey.getBankCode() == null     || mapKey.getBankCode().equals(bankCode))    return true;  }  return false; } public String toString() {  return date.toString() + accountNo + bankCode; }public int hashCode() { int temp =(date.toString() + accountNo + bankCode).hashCode();   return temp; } public String getAccountNo() {  return accountNo; } public String getBankCode() {  return bankCode; } public Date getDate() {  return date; }}