第五题 （Map）设计Account 对象如下：
private long id;
private double balance;
private String password;
要求完善设计，使得该Account 对象能够自动分配id。 给定一个List 如下：
List list = new ArrayList();
list.add(new Account(10.00, “1234”));
list.add(new Account(15.00, “5678”));
list.add(new Account(0, “1010”));
要求把List 中的内容放到一个Map 中，该Map 的键为id，值为相应的Account 对象。 最后遍历这个Map，打印所有Account 对象的id 和余额。
package Test03;
public class Account {
private long id;
private double balance;
private String password;
Account(double balance,String password)
{
this.balance=balance;
this.password=password;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
package Test03; import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map; public class TestAccount { public static void main(String[] args) { List<Account> list = new ArrayList<>(); list.add(new Account(10.00, "1234"));
list.add(new Account(15.00, "5678"));
list.add(new Account(0, "1010")); Map<Long,Account> m1 = new HashMap<>();
m1.put((long) 0, list.get(0));
m1.put((long) 1, list.get(1));
m1.put((long) 2, list.get(2)); for(Long k:m1.keySet()) //遍历
{
System.out.println(m1.get(k).getBalance());
} } }