Java-集合练习5

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 com.jihelianxi;

import java.util.Random;

public class Lianxi5 {
    
    private long id;  
    private double balance;  
    private String password;
    Random ra=new Random();
    
   public Lianxi5(double balance, String password) {
        super();
        this.id=ra.nextInt(1000000)+1000000;
        this.balance = balance;
        this.password = password;
    }
   
    public Lianxi5() {
    super();
}

    @Override
    public String toString() {
        return "Lianxi5 [balance=" + balance + ", 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;
    }


}

测试;

package com.jihelianxi;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Lianxi51 {

    public static void main(String[] args) {
        
        Lianxi5 lx=new Lianxi5();
        
        List<Lianxi5> li=new ArrayList<Lianxi5>();
        
        
        li.add(new Lianxi5(10.00, "1234"));
        li.add(new Lianxi5(15.00, "5678"));
        li.add(new Lianxi5(0, "1010"));
        
        Map<Long, Lianxi5> ma=new HashMap<>();
        
        for(Lianxi5 l:li)
        {
            ma.put(l.getId(), l);
        }
        
        for(Long lo:ma.keySet())
        {
            System.out.println("id="+lo+" 余额="+ma.get(lo).getBalance());
        }

    }

}

结果：