Question

这是我的观点：我需要使用默认的woodType创建一个Chair对象数组。我能够声明数组本身，但显然所有的值都是null。当我尝试实例化数组中的每个Chair对象时，我会收到错误。在尝试实例化时，我不确定我做错了什么，请帮助。

public class PAssign3 {

public static void main(String[] args) {

    TableSet set1 = new TableSet();

    TableSet set2 = new TableSet(5, 7, 4);
//        Chair chr1 = new Chair();//this works properly, setting wood as Oak
//        Chair chr2 = new Chair("Pine");//works

    }

}

class TableSet {

    Table table = new Table();

    private int numOfChairs = 2;

    //creates an array that can hold "numOfChairs" references to same num of 
    //chair objects; does not instantiate chair objects!!!
    Chair[] chairArr = new Chair[numOfChairs];

    //instantiate each chair object for length of array
    //this loop does not work; Error: illegal start of type
    for (int i = 0; i < numOfChairs.length; i++) {
        chairArr[i] = new Chair();
        }

    public TableSet() {
    }

    public TableSet(double width, double length, int numOfChairs) {
        table = new Table(width, length);
        this.numOfChairs = numOfChairs;
        chairArr = new Chair[numOfChairs];

        //this loop also does not work; Error: int cannot be dereferenced
        for (int i = 0; i < numOfChairs.length; i++) {
            chairArr[i] = new Chair();
        }
    }

    public void setNumOfChairs(int numOfChairs) {
        this.numOfChairs = numOfChairs;
    }

    public int getNumOfChairs() {
        return numOfChairs;
    }

    public String getChairWoodType() {
        return chairArr[0].getWoodType();
    }
}

class Table {

    private double width = 6;
    private double length = 4;

    public Table() {
    }

    public Table(double width, double length) {
        this.width = width;
        this.length = length;
    }

    public void setWidth(double width) {
        this.width = (width < 0) ? 0 : width;
    }

    public void setLength(double length) {
        this.length = (length < 0) ? 0 : width;
    }

    public double getWidth() {
        return width;
    }

    public double getLength() {
        return length;
    }
}

class Chair {

    private String woodType = "Oak";

    public Chair() {
    }

    public Chair(String woodType) {
        this.woodType = woodType;
    }

    public void setWoodType(String woodType) {
        this.woodType = woodType;
    }

    public String getWoodType() {
        return woodType;
    }
}

Answer 1

int是Java中的一个简单类型，没有任何方法或字段。只需省略此.length，错误就消失了。在我看来它已经存储了实际的椅子数量（2）。

无法用Java创建对象数组

1 个答案: