java - 如何打印出HashMap的值？输出如 xxx@da52a1

Question

我有两个类。

Main.java

import java.util.HashMap;
import java.util.Map;

public class Main {
    Map<Integer, Row> rows = new HashMap<Integer, Row>();
    private Row col;

    public Main() {
        col = new Row();
        show();
    }

    public void show() {
        // col.setCol("one", "two", "three");
        // System.out.println(col.getCol());

        Row p = new Row("raz", "dwa", "trzy");
        Row pos = rows.put(1, p);
        System.out.println(rows.get(1));

    }

    public String toString() {
        return "AA: " + rows;
    }

    public static void main(String[] args) {
        new Main();
    }
}

和 Row.java

public class Row {

    private String col1;
    private String col2;
    private String col3;

    public Row() {
        col1 = "";
        col2 = "";
        col3 = "";
    }

    public Row(String col1, String col2, String col3) {
        this.col1 = col1;
        this.col2 = col2;
        this.col3 = col3;
    }

    public void setCol(String col1, String col2, String col3) {
        this.col1 = col1;
        this.col2 = col2;
        this.col3 = col3;
    }

    public String getCol() {
        return col1 + " " + col2 + " " + col3;
    }
}

输出总是看起来像“Row@da52a1”或类似的。如何解决这个问题？我希望能够通过轻松访问每个字符串来执行类似的操作:

str="string1","string2","string3"; // it's kind of pseudocode ;)
rows.put(1,str);
rows.get(1);

如您所见，我创建了 Row 类来将其用作 Map 的对象，但我不知道我的代码有什么问题。

Answer 1

将 toString 方法重写为 Row 类，如下所示:

@Override
public String toString() {
    return col1 + " " + col2 + " " + col3;
}