java error: constructor in class cannot be applied

Question

public class WaterHeater{

    public double Kilowatts;
    public double Water;
    public double Joules;
    public double Temp;
    public double Jkg;
    public double Energy;
    public double Time;

  //Constructor method

  public WaterHeater (double Water, double Kilowatts, double Joules, double Temp, double Jkg)  {

    this.Water = Water;
    this.Kilowatts = Kilowatts;
    this.Joules = Joules;
    this.Temp = Temp;
    this.Jkg = Jkg;
  }

    //Accessor for Kilowatts
    public double Kilowatts(){
    return Kilowatts;
    }

    //Accessor for Water
    public double Water(){
    return Water;
    }

    //Method for Energy used
    public double Energy(){
    Energy = Water*Jkg*Temp;
    return Energy;
    }

    //Method for Time to boil
    public double Time(){
    Time = Energy/Kilowatts;
    return Time;
    }
    }

//Test class

 public class Kettle extends WaterHeater{

  public static void main( String args[] ) 
  {

    WaterHeater Kettle = new WaterHeater(1, 2, 3600, 70, 4200); 

    System.out.println("\nWater: " +Kettle.Water + " L" +
    "\nKilowatts: " + Kettle.Kilowatts + " KW"+
    "\nEnergy used: " +Kettle.Energy() + " J" +
    "\nTime to boil: " +Kettle.Time() + " Seconds");


  }

}

错误：classWaterHeater 中的构造函数 WaterHeater 无法应用于给定类型。 要求：双倍，双倍，双倍，双倍，双倍 发现：没有参数 原因：实际和正式的参数列表长度不同

Answer 1

使用 Kettle 作为变量名 和 class 的名称将无法正常工作。

一个有用的约定（Java 程序员遵循的约定）是对变量名使用驼峰式命名（注意小写 c），对 class 个名称使用驼峰式命名。

所以保持 class 名称不变，但重命名变量：

WaterHeater kettle = new WaterHeater(...

Answer 2

由于您在 WaterHeater 中编写了构造函数，因此如果不为 Kettle 编写调用 WaterHeater 构造函数的构造函数，就无法扩展 WaterHeater。您可以按如下方式进行：

public Kettle(double water, double kilowatts, double joules, double temp, double jkg) {
    super(water, kilowatts, joules, temp, jkg);
}

另一方面，如果您只是希望 Kettle 成为测试 WaterHeater 的 class，那么您只需要删除单词 extends WaterHeater。

Answer 3

代码有很多约定错误，但是您尝试使用的代码存在问题 运行 是这需要添加到 Kettle class

public Kettle(double Water, double Kilowatts, double Joules, double Temp, double Jkg) {
    super(Water, Kilowatts, Joules, Temp, Jkg);     
}

其他指针

对属性使用 camelcase/lowercase 和私有而不是 public

public double Kilowatts;
public double Water;
public double Joules;
public double Temp;
public double Jkg;
public double Energy;
public double Time;

应该是

private double kilowatts;
private double water;
private double joules;
private double temp;
private double jkg;
private double energy;
private double time;

使用Accessors and Mutators.

public double Kilowatts() {
    return Kilowatts;
}

应该是

public double getKilowatts() {
    return kilowatts;
}
public void setKilowatts(final String kilowatts) {
    this.kilowatts = kilowatts;
}

主要 class 也会像这样

public class Kettle extends WaterHeater {

    public Kettle(double water, double kilowatts, double joules, double temp, double jkg) {
        super(water, kilowatts, joules, temp, jkg);     
    }

    public static void main(String args[]) {

        WaterHeater kettle = new WaterHeater(1, 2, 3600, 70, 4200);

        System.out.println("\nWater: " + kettle.getWater() + " L" + "\nKilowatts: " + kettle.getKilowatts() + " KW" + "\nEnergy used: " + kettle.getEnergy() + " J"
            + "\nTime to boil: " + kettle.getTime() + " Seconds");
    }
}