Question

这是我重新编写的新编码：

ThreeDPoint.java

public class ThreeDPoint{

private double x, y, z;

public threeDPoint(){
    coordX=0;
    coordY=0;
    coordZ=0;
}

public threeDPoint(double x, double y, double z){
    coordX = x;
    coordY = y;
    coordZ = z;
}

public double getCoord(double x, double y, double z){
    return coordX;
    return coordY;
    return coordZ;
}

}

Main.java

import java.util.Scanner;

public class Main {

      double coordX, coordY, coordZ;

public static void main(String[] args){

    threeDPoint myThreeDPoint=new threeDPoint();

    Scanner sc=new Scanner(System.in);
    String coordX, coordY, coordZ;

    System.out.println("Input Coordinate X");
    myThreeDPoint.coordX(sc.nextDouble());

    System.out.println("Input Coordinate Y");
    myThreeDPoint.coordY(sc.nextDouble());

    System.out.println("Input Coordinate Z");
    myThreeDPoint.coordZ(sc.nextDouble());


}

}

它给了我这些错误：构建输出： C：\ Users \ BurneySoo \ Documents \ Main.java:8:error：找不到符号 threeDPoint myThreeDPoint = new threeDPoint（）; ^ 符号：class threeoint 位置：班级主要 C：\ Users \ BurneySoo \ Documents \ Main.java:8:error：找不到符号 threeDPoint myThreeDPoint = new threeDPoint（）; ^ 符号：class threeoint 位置：班级主要 2个错误

一般输出： 错误：无法找到或加载主类

我做错了什么？

非常感谢Gagandeep代码。不知怎的，我尝试了它们，但它发出的错误比以前更多。

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java：5：错误：方法声明无效;需要返回类型

public threeDPoint(){
       ^

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java：11：错误：方法声明无效;需要返回类型

public threeDPoint(double x, double y, double z){
       ^

C：\ Users \ BurneySoo \ Documents \ Main.java:14：错误：找不到符号

myTreeDPoint.coordX(sc.nextLine());
^

symbol：变量myTreeDPoint location：class Main

C：\ Users \ BurneySoo \ Documents \ Main.java:17：错误：找不到符号

myTreeDPoint.coordY(sc.nextLine());
^

symbol：变量myTreeDPoint location：class Main

C：\ Users \ BurneySoo \ Documents \ Main.java:20:error:找不到符号

myTreeDPoint.coordZ(sc.nextLine());
^

symbol：变量myTreeDPoint location：class Main

C：\ Users \ BurneySoo \ Documents \ Main.java：22：错误：非静态变量coordY无法从静态上下文引用

myThreeDPoint.setCoord(coordX, coordY, coordZ);
                               ^

C：\ Users \ BurneySoo \ Documents \ Main.java：22：错误：无法从静态上下文引用非静态变量coordZ

myThreeDPoint.setCoord(coordX, coordY, coordZ);
                                       ^

C：\ Users \ BurneySoo \ Documents \ Main.java：22：错误：类ThreeCooint中的方法setCoord不能应用于给定的类型;

myThreeDPoint.setCoord(coordX, coordY, coordZ);
             ^

必需：双倍，双倍，双倍发现：String，double，double reason：实际参数String不能通过方法调用转换转换为double

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java：6：错误：找不到符号

    coordX=0;
    ^

符号：变量coordX location：class ThreeDPoint

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java：7：错误：找不到符号

    coordY=0;
    ^

符号：变量coordY location：class ThreeDPoint

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java:8:error：找不到符号

    coordZ=0;
    ^

符号：变量coordZ location：class ThreeDPoint

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java:12：错误：找不到符号

    coordX = x;
    ^

符号：变量coordX location：class ThreeDPoint

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java:13：错误：找不到符号

    coordY = y;
    ^

符号：变量coordY location：class ThreeDPoint

C：\ Users \ BurneySoo \ Documents \ ThreeDPoint.java:14：错误：找不到符号

    coordZ = z;
    ^

符号：变量coordZ location：class ThreeDPoint

14个错误

它仍然不会提示我在常规输出中输入坐标X. 它只给了我：

错误：无法找到或加载主类

Answer 1

这里的问题是你没有调用构造函数，而是试图调用方法。

为您的threeDPoint类创建一个构造函数，然后使用setter设置字段coordX。你不能打电话

threeDPoint myThreeDPoint=new coordX();

因为这是一个方法，而不是构造函数。你想要的是你的threeDPoint类中的构造函数，如下所示：

    public threeDPoint(args){
//dostuff
}

然后设置你的Coords就像

public void setCoordx(double coordx){
this.coordx = coordx}

此外，作为数据隐藏的问题，请务必将您的字段视为私有或受保护。

protected double coordX;

Answer 2

你必须写

threeDPoint myThreeDPoint=new threeDPoint("Send Arguments Here");

在main方法中，要创建一个对象，现在使用此对象，您必须访问方法myThreeDPoint.coordX(11.11);

将您的ThreeDPoint课程更改为：

public class ThreeDPoint
{
    private double x, y, z;

    public ThreeDPoint()
    {
        this.x = 0;
        this.y = 0;
        this.z = 0;
    }

    public ThreeDPoint(double x, double y, double z)
    {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    public double getCoordX()
    {
        return this.x;
    }

    public double getCoordY()
    {
        return this.y;
    }

    public double getCoordZ()
    {
        return this.z;
    }
}

现在将此类的对象设为

ThreeDPoint myThreeDPoint = new ThreeDPoint();

所以你的主类看起来像这样：

import java.util.Scanner;
public class Main
{
    double coordX, coordY, coordZ;

    public static void main(String[] args)
    {
        ThreeDPoint myThreeDPoint = new ThreeDPoint();

        Scanner sc=new Scanner(System.in);
        String coordX, coordY, coordZ;

        System.out.println("Input Coordinate X");
        coordX = sc.nextDouble();

        System.out.println("Input Coordinate Y");
        coordY = sc.nextDouble();

        System.out.println("Input Coordinate Z");
        coordZ = sc.nextDouble();

        // This will initialize your Constructor with Arguments.
        ThreeDPoint myThreeDPointArgConst = new ThreeDPoint(coordX, coordY, coordZ);

        coordX = myThreeDPointArgConst.getCoordX();
        System.out.println("Co-ordinate X is : " + coordX);

        coordY = myThreeDPointArgConst.getCoordY();
        System.out.println("Co-ordinate Y is : " + coordY);

        coordZ = myThreeDPointArgConst.getCoordZ();
        System.out.println("Co-ordinate Z is : " + coordZ);        

        // This will initialize the no-arg constructor.
        ThreeDPoint myThreeDPoint = new ThreeDPoint();

        coordX = myThreeDPoint.getCoordX();
        System.out.println("Co-ordinate X is : " + coordX);

        coordY = myThreeDPoint.getCoordY();
        System.out.println("Co-ordinate Y is : " + coordY);

        coordZ = myThreeDPoint.getCoordZ();
        System.out.println("Co-ordinate Z is : " + coordZ);        
    }
}

错误：找不到符号（坐标）

2 个答案: