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I likeThatMeow
Asked: 2020-09-22 07:53:23 +0800 CST 2020-09-22 07:53:23 +0800 CST

如何打印类类型数据？

  • 772

在方法queueAnalysis中，当我命令打印 System.out.println("Original: " + queue + "\n");时 System.out.println("colados: " + names + "\n");， System.out.println("Cola final: " +queue);它给我作为输出direcciones de memoria，null并且direcciones de memoria，我已经尝试应用 aiterator并应用类类型转换Customer，但即便如此，它仍然继续提供内存地址作为输出。为什么？，

我该如何解决这个问题？

class Customer {

String name;
int ticket;

Customer(String name, int ticket) {
    this.name = name;
    this.ticket = ticket;

}

String getName() {
    return name;

}

int getTicket() {
    return ticket;
}
}

public class Main {

public static void main(String[] args) {
    Queue<Customer> queue = new LinkedList<>();
    queue.add(new Customer("a1", 1));
    queue.add(new Customer("a2", 2));
    queue.add(new Customer("a3", -1));
    queue.add(new Customer("a4", -1));

    queueAnalysis(queue);
}

public static void queueAnalysis(Queue<Customer> queue) {

    System.out.println("Original: " + queue + "\n");
    String names[] = null;
    int cant = 0;
    int tam = queue.size();

    for (int i = 0; i < tam; i++) {
        if (queue.peek().getTicket() == -1) {
            names[i] = queue.peek().getName();
            cant++;
            queue.poll();


        }

    }
    System.out.println("colados: " + names + "\n");
    System.out.println("Cola final: " +queue); 

    //Customer c;
    for (Iterator it = queue.iterator(); it.hasNext();) {
        System.out.println((Customer) it.next());
    }

}

}
java

3 Answers

  1. 您不能直接打印 arrayList 或向量：

    for( Customer c: queue ){
  System.out.println( "Original: " + c.getName( ) + "" + c.getTicket( ));
}
    • 2

  2. 如果您想要显示对象的名称或其他内容，只需覆盖Customer类的ToString()方法。

    public class Customer {

    String name;
    int ticket;

    public Customer(String name, int ticket) {
        this.name = name;
        this.ticket = ticket;

    }

    String getName() {
        return name;

    }

    int getTicket() {
        return ticket;
    }


    @Override
    public String toString(){
        return getName()+ "-" + getTicket();        
    }
}
    • 2
  3. Best Answer

    除了@Edu3D 给出的答案之外，您还必须更改从队列和fila最后一个队列中获取数据的方式，这是因为您没有通过索引访问队列，并且当您访问队列时，peek()或者poll()它总是在对象上是在headde行，这里我修改方法

    public static void queueAnalysis(Queue<Customer> queue) {
  System.out.println("Original: " + queue + "\n");
  Queue<Customer> colados = new LinkedList<>();
  Queue<Customer> noColados = new LinkedList<>();
  while(!queue.isEmpty()){
    if (queue.peek().getTicket() == -1) {
      colados.add(queue.poll());
    }else{
      noColados.add(queue.poll());
    }
  }
  System.out.println("colados: " + colados + "\n");
  System.out.println("Cola final: " + noColados);
  //Customer c;
  for (Iterator it = queue.iterator(); it.hasNext();) {
    System.out.println((Customer) it.next());
  }
}

    这仅在您进行@Edu3D 提到的更改以覆盖toString()类方法时才有效Customer

    public class Customer {
  String name;
  int ticket;

  public Customer(String name, int ticket) {
    this.name = name;
    this.ticket = ticket;
  }
  String getName() {
    return name;
  }
  int getTicket() {
    return ticket;
  }

  @Override
  public String toString(){
    return getName()+ "-" + getTicket();        
  }
}
    • 2