JTable two-dimensional object array

Question

May this question is repeated but I tried most of the solution but none of them fit in my problem. Referring to this page : https://docs.oracle.com/javase/tutorial/uiswing/components/table.html

I want to create the JTable to read from objects from my custom class.As an initial step, I want to test the looping with the JTable. As follow:

Object[][] tripsData =new Object[3][6];
for(int j=0; j< 3;j++)
        for(int i =0; i< 6;i++)
        {   tripsData[j][i]= new Object[] {"Kathy", "Smith","wait",  "Snowboarding", 5, "false"};
        }

The code works fine except the output it shows like this:

 [Ljava.lang.Object;@41488024
 [Ljava.lang.Object;@54c83ae1
 [Ljava.lang.Object;@161a4f2c

I tried to use, toString() and valueOf(), but the same thing. Any suggestion to solve

[Ljava.lang.Object;@41488024 is the toString method of Object[] — xingbin
– xingbin, Commented May 8, 2018 at 13:55
@NengLiu so, how can I show the original text ?. I'm forced to use Object instead of String to put it in the JTable. — asma
– asma, Commented May 8, 2018 at 14:06
And, do you really want to make tripsData an array? It is a single element in the matrix! — xingbin
– xingbin, Commented May 8, 2018 at 14:10
@NengLiu no it's not a single element. It contain dynamic data. — asma
– asma, Commented May 8, 2018 at 14:14

evnica · Accepted Answer · 2018-05-08 15:05:55Z

1

The problem is you are creating a three-dimensional array instead of the 2D that you need. In your code, you use

tripsData[j][i]= new Object[] {"Kathy", "Smith","wait",  "Snowboarding", 5, "false"};

thus "Kathy" in the resulting Object has an index [j][i][0], "Smith" has an index [j][i][1] and so on. Populate your array like so:

Object[][] tripsData =new Object[3][6];
        for(int j=0; j< 3;j++) {
            tripsData[j] = new Object[]{"Kathy", "Smith", "wait", "Snowboarding", 5, "false"};
        }

Then both this

    for (Object[] row : tripsData) {
        for (int j = 0; j < data[0].length; j++) {
            System.out.print(row[j]);
            System.out.print("\t");
        }
        System.out.print("\n");
    }

and this

for (Object[] row : tripsData) {
    System.out.println(Arrays.toString(row));
}

will work fine

answered May 8, 2018 at 15:05

evnica

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2 Comments

asma Over a year ago

THNAK YOU very much, yes you are right. As I put the whole columns in the object I shouldn't use it as a single cell.

evnica Over a year ago

Happy to help =)

TheJavaGuy-Ivan Milosavljević · Accepted Answer · 2018-05-08 13:53:53Z

0

You can use Arrays.toString(), somewhat similar to this snippet:

    Object[][] arr = new Object[2][2];
    arr[0][0] = "00";
    arr[0][1] = "01";
    arr[1][0] = "10";
    arr[1][1] = "11";
    System.out.println(Arrays.toString(arr[0]));
    System.out.println(Arrays.toString(arr[1]));

This will print

[00, 01]
[10, 11]

answered May 8, 2018 at 13:53

TheJavaGuy-Ivan Milosavljević

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3 Comments

asma Over a year ago

Thank you for your reply, but it doesn't work with me.

TheJavaGuy-Ivan Milosavljević Over a year ago

It doesn't work in what way? What output you see when you write System.out.println(tripsData[0]); after your example? Show us some code you tried, otherwise it's very difficult to help you.

asma Over a year ago

Thank you for your support, It was solved by the next comment by evnica.

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