Question

在我的程序中，我正在尝试调用一个名为readData的方法，该方法将读取一个名为carbon.data的文件。它将做的是获取该文件中的所有值并将其放入数组中。我只是不确定如何调用ReadData方法。这是代码：

import java.io.*;
import java.util.*;
public class Report{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        String filename = scanner.next();
        Scanner input = readFile(filename); 
    }

    public static Scanner readFile(String filename){
        File input = new File(filename);
        Scanner sc = null;
        try{
            sc = new Scanner(input);
        }
        catch(FileNotFoundException e){
            System.out.println("Filename not valid");
            System.exit(-1);
        }
        return sc;
    }

    public static CO2Data[] readData(String filename){
    File input = new File(filename);
        Scanner sc = null;
        try{
            sc = new Scanner(input);
        }
        catch(FileNotFoundException e){
            System.out.println("Filename not valid");
            System.exit(-1);
        }
    String info = sc.nextLine();
    int total = sc.nextInt();
    CO2Data[] arr = new CO2Data[total];
    for(int i=0; i<10;i++){
        arr[i] = new CO2Data();
        }
    for(int i=0; i<10;i++){ 
        arr[i].setCountry(sc.next());
        arr[i].setTotalCO2(sc.nextDouble());
        }
    return arr;
    }
}

此代码是名为CO2Data的类的一部分。这是该类的代码：

public class CO2Data {

    private String country;
    private double totalCO2;

    public CO2Data() {
        country = "";
        totalCO2 = 0;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public double getTotalCO2() {
        return totalCO2;
    }

    public void setTotalCO2(double totalCO2) {
        this.totalCO2 = totalCO2;
    }

Answer 1

由于readData是静态的，你可以将其称为Report.readData（＆＃34; blah＆＃34;）;

Answer 2

尝试在主打电话中将其打印出来 -

public static void main(String[] args){
            Scanner scanner = new Scanner(System.in);
            String filename = scanner.next();
            CO2Data[] aDataArray  = null
            aDataArray = readData(filename); 
            if(aDataArray != null) {
               for(int i = 0; i < aDataArray.length; i++) {
                    System.out.println("Country:" + aDataArray[i].getCountry());
                    System.out.println("CO2 Level:" + aDataArray[i].getTotalCO2());
                }
            }
        }

Answer 3

如果从Report类中调用它，你可以写

CO2Data[] data = readData(filename);

如果你想从另一个类调用它，你必须在方法名前加上类名（因为它是一个静态方法）

CO2Data[] data = Report.readData(filename);

如何在Java中调用以下方法？

3 个答案: