在Java中打印对象的二维数组

Question

I have a 2-d array which contains objects.does anyone knows how can i print this array?Because when i use the following code doesn't print the contain of the object but print symbols.

Humans [][]cells= new Humans [7][7];

for (int row=0; row<cells.length; row++) {
      for (int col=0; col<cells[row].length; col++) {


            System.out.print("  " + cells[row][col]);


           } 
} 

Answer 1

You need to add a toString() to your Humans object if you want to include it in string concatenation.

public String toString() {
    return "Name: " + name + " age: " + age + " shoe size: " + shoeSize;
}

Answer 2

you need to use toString , and make sure the instances in the 2d array implement it appropriately.

In your inner most loop something like

Human current = cells[row][col]; 
// possibly do a null check
System.out.print(current.toString());

Be sure to implement toString on Human .

Answer 3

You need to override the method toString in your Human class to print any details of the class you want (I'm assuming name and stuff) and then instead of :

cells[row][col]

you should write :

cells[row][col].toString()

Answer 4

As @hvgotcodes has said you need to ensure that your Human class has implemented the toString method. For example if a Human just contains a single number (the person's age), the most basic it might look like this:

class Human {
    int age;
    public Human(int age){
        this.age = age;
    }       
    @Override
    public String toString(){
        return "[Human: age :=" + age + "]"; //or whatever's appropriate!
    }
}

To then print your 2d array of these objects you can write:

for(int i = 0; i < cells.length; i++){
    for(int j = 0; j < cells[i].length; j++){
        System.out.print(cells[i][j]); //invokes toString method in Human..
        if(j < cells[i].length -1)
            System.out.print(", ");
        }
        System.out.println();
    }
}

Answer 5

Override the toString() method in your humans class and print what you want to be printed for a human. Then use

Arrays.toString(cells);

to print your array.

Answer 6

Can you override the Humans toString()?

Edit: Here is good reference http://www.javapractices.com/topic/TopicAction.do?Id=55

Answer 7

您需要重写Human类中的toString以满足您的需求。

Answer 8

First, you need to override the toString() method of the Humans object to return a String that represents the contents of an instance of Humans.

Next, you'll probably want to print a new line after the inner for loop completes, otherwise you're going to print the entire contents of the entire 2D array on just one line (unless that's what you're going for here).