錯誤：找到合適的構造函數但找不到符號

Question

我目前正在創建一個具有子類的代碼，該子類將繼承超類的數據字段和方法。 子類還將有一個額外的字段，但我想從一個字段開始。

我正在使用一個名為 Bird.csv 的輸入文件，它有 4 列。 我想用我已經做過的 10 行數據添加第 5 行。

我正在使用該子類來獲取和設置字段的方法並對其進行初始化。

我的代碼目前有 4 個錯誤，我真的需要幫助來解決我需要修復的問題。

代碼：

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class TestingCode {

   public static void main(String[] args) {
   //error checking for commandline input
      if(args.length != 1){
         System.out.println("Please enter at least one input file into the argument.");
         //terminates the program if more than 1 is entered
         System.exit(1);
      }

      String csvFile = args[0];
      String line = "";
      String cvsSplitBy = ",";

      List<HawaiiNativeForestBirds>  listofBirds = new ArrayList<HawaiiNativeForestBirds>();
      try (BufferedReader br = new BufferedReader(new FileReader(csvFile))) {

         while ((line = br.readLine()) != null) {

            // use comma as separator
            String[] bird = line.split(cvsSplitBy);
            HawaiiNativeForestBirds Hawaiinbird = new HawaiiNativeForestBirdsWithMoreData(bird[0],bird[1],bird[2],Integer.valueOf(bird[3]),bird[4]);
            listofBirds.add(Hawaiinbird);
         }
      } 
      catch (IOException e) {
         e.printStackTrace();
      }

      HawaiiNativeForestBirds[]  hbirds=new        HawaiiNativeForestBirds[listofBirds.size()];
      System.out.println("index   " + "    element   ");  
      int i=0;
      for (HawaiiNativeForestBirds hbird:hbirds){
         i++;
         System.out.println(i+"            "+hbird);
      }

      hbirds= listofBirds.toArray(new HawaiiNativeForestBirds[listofBirds.size()]);

      System.out.println("index   " + "name   "+ "   Scientific Name     "+ "        Color     " +       "      Population");        
      i=0;
      for (HawaiiNativeForestBirds hbird:hbirds){
         i++;
         System.out.println(i+"   "+hbird.toString());
      }

      hbirds= listofBirds.toArray(new HawaiiNativeForestBirds[listofBirds.size()]);

      System.out.println("index   " + "name   "+ "   Scientific Name     "+ "        Color     " +       "      Population");        
      i=0;
      for (HawaiiNativeForestBirds hbird:hbirds){
         i++;
         System.out.println(i+"   "+hbird.toString2());
      }

      hbirds= listofBirds.toArray(new HawaiiNativeForestBirds[listofBirds.size()]);

      System.out.println("index   " + "name   "+ "   Scientific Name     "+ "        Color     " +       "      Population" +       "      Author");        
      i=0;
      for (HawaiiNativeForestBirds hbird:hbirds){
         i++;
         System.out.println(i+"   "+hbird.toString3());
      }
   } 
}

class HawaiiNativeForestBirds {
   protected String name;
   protected String scientificname;
   protected String color;
   protected Integer population;

   public HawaiiNativeForestBirds(){
   }

   public HawaiiNativeForestBirds(String name, String scientificname,
        String color, Integer population) {
      super();
      this.name = name;
      this.scientificname = scientificname;
      this.color = color;
      this.population = population;
   }

   // getters and setters hidden

   public String toString() {
      String output = name + "     " + scientificname + "             " + color + "           " + population;
      return output;
   }

   public String toString2() {
      population = population + 1;
      String output = name.toUpperCase() + "     " + scientificname.toUpperCase() + "             "+ color.toUpperCase() + "           " + population;
      return output;
   }
}

類HawaiiNativeForestBirdsWithMoreData ：

class HawaiiNativeForestBirdsWithMoreData extends HawaiiNativeForestBirds { 

    private String author;

    public HawaiiNativeForestBirdsWithMoreData(){  
    }

    public HawaiiNativeForestBirdsWithMoreData(String name, String scientificname,
        String color, Integer population, String author) {
        super(name, scientificname, color, population);
        this.author = author;
    }  

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String toString3() {
        population = population + 1;
        String output = name.toUpperCase() + "     " + scientificname.toUpperCase() + "             " + color.toUpperCase() + "           " + population + "           " +author.toUpperCase();
        return output;
    }
}

這是我的錯誤：

TestingCode.java:84: error: cannot find symbol
         System.out.println(i+"   "+hbird.toString3());
                                         ^
  symbol:   method toString3()
  location: variable hbird of type HawaiiNativeForestBirds
1 error

這是我的輸入文件：

Answer 1

問題可能不在於你的構造函數你如何聲明一只鳥的實例。 你有，構造函數為（字符串，字符串，字符串，整數，字符串），但你的數據是按順序排列的（字符串，字符串，整數，字符串）。 仔細檢查 csv 文件中的順序，確保它與您傳入參數的順序相匹配。

編輯：檢查 csv 文件后。 人口是列表中的第 4 項，所以

 HawaiiNativeForestBirds Hawaiinbird= new HawaiiNativeForestBirds(bird[0],bird[1],Integer.valueOf(bird[2]), bird[3]);

此外，正如所指出的，傳入了第 5 個參數，因此您需要更新構造函數以適應它。

編輯最后一個錯誤：

使用 toString3() 方法所需的數組數據類型並不多。 您只能訪問 toString() 和 toString2()，而它的類型是 HawaiiNativeForestBirds，即使實際類型包含 toString3()。