Java打印数组列表

Question

这是我的 2 个类(class)，它们有效。我想将Member添加到Lan的ArrayList中。我的问题是，我似乎无法打印出 Lan 的 ArrayList 中设置的成员、名称和别名或只是名称。当我打印出来时:Member@1279d2f，有什么想法吗？ :S

import java.util.ArrayList;

public class Lan
{

private ArrayList<Member> members;



    public Lan()
    {
      members = new ArrayList<Member>();

    }

    public void addMember(Member newMember)
    {
        if(newMember.getBalance() >= 200)
        {
            this.members.add(newMember);
        }
        else
        {
            System.out.println("You dont have enough money to enter");
        }

    }
   public void printMembers(){

       System.out.println("People attending");
       for(Member member : members){

          System.out.println(member);
       }

   }

}


public class Member
{

    private String name;
    private String alias;
    private int balance;


    public Member(String fullName, String nickname)
    {
        this.name = fullName;
        this.alias = nickname;
        this.balance = 0;
    }
    public void setBalance(int account)
    {
        if(account > 0)
        {
            balance = balance + account;
        }
        else
        {
            System.out.println("You have not entered a valid number");
        }
    }

    public String getName()
    {
        return name;
    }
    public String getAlias()
    {
        return alias;
    }

    public int getBalance()
    {
        return balance;
    }
}

Answer 1

您必须为您的 Member 类定义一个 toString() 方法:

public class Member { 

  private String name;
  private String alias;
  private int balance;


  public Member(String fullName, String nickname)
  {
      this.name = fullName;
      this.alias = nickname;
      this.balance = 0;
  }
  public void setBalance(int account)
  {
      if(account > 0)
      {
          balance = balance + account;
      }
      else
      {
          System.out.println("You have not entered a valid number");
      }
  }

  public String getName()
  {
      return name;
  }
  public String getAlias()
  {
      return alias;
  }

  public int getBalance()
  {
      return balance;
  }

  @Override
  public String toString() {
    return this.name + "\t" + this.balance;
  }

}

如果您的自定义类没有 toString() 方法，您将打印它在内存中的位置。如果您还想在成员(member)中打印其他信息，请修改我为您提供的方法。