具有链表实现和存储文本文件的哈希表 [英] Hash table with linked list implementation and storing text file

问题描述

我想使用链表和链表实现自己的哈希表，但是我很难确定如何在main方法中使用实现.我需要读取一个用数据分隔的逗号分隔值文件，并将名称存储为键，并将两个浮点存储为值.我知道我需要使用面向对象的编程，但是我很难通过自己的实现来访问数据.

I want to implement my own hash table using chaining and linked list but I am having a hard time figuring out how to use the implementation in the main method. I need to read a comma separated values file with data and store the names as keys and the two floating points as a value. I know I need to use object oriented programming but I having a difficult time accessing my data using my implementation.

这是我的代码: 公共类LinkedListHash {

Here is my code: public class LinkedListHash{

     String key;
     String value;
     LinkedListHash next;
    public LinkedListHash(){
    }
    LinkedListHash(String key, String value){
        this.key = key;
        this.value = value;
        this.next = null;
    }
    public String getValue(){
        return value;
    }
    public void setValue(String value){
        this.value = value;
    }
    public String getKey(){
        return key;
    }
    public LinkedListHash getNext(){
        return next;
    }
    public void setNext(LinkedListHash next){
        this.next = next;
    }

   class Hashtable {
    int size = 0;
    LinkedListHash[] table;
    Hashtable(){
        table = new LinkedListHash[size];
        for (int i = 0; i < size; i++){
            table[i] = null;
        }
    }
    public String get(String key){
        int hash = key.hashCode();
        if (table[hash] == null){
            return null;
        }
        else {
            LinkedListHash input = table[hash];
            while (input != null && input.getKey() != key){
                input = input.getNext();
            }
            if (input == null){
                return null;
            }
            else {
                return input.getValue();
            }
        }

    }
    public void put(String key, String value){
        int hash = key.hashCode();
        if (table[hash] == null){
            table[hash] = new LinkedListHash(key, value);
        }
        else {
            LinkedListHash input = table[hash];
            while (input.getNext() != null && input.getKey() != key){
                input = input.getNext();
            }
            if (input.getKey() == key){
                input.setValue(value);
            }
            else {
                input.setNext(new LinkedListHash(key, value));
            }
        }
    }

  }
}

 public static void main(String[] args) throws FileNotFoundException{

     Hashtable<String, String> tbl = new Hashtable<String, String>();

     String path = args[0];

     if(args.length < 1) {
            System.out.println("Error, usage: java ClassName inputfile");
        System.exit(1);
        }

        Scanner reader = new Scanner(new FileInputStream(args[0]));

        while((path = reader.nextLine()) != null){
            String parts[] = path.split("\t");

            tbl.put(parts[0], parts[1]);
         } reader.close();

 }  }

任何可以改善我的代码的方式都会有所帮助. 请记住，我不是一个非常有经验的程序员，所以对于任何可怕的错误我深表歉意.

Any way I could improve my code would be helpful. Keep in mind I am not a very experienced programmer so I apologize for any horrendous mistakes.

推荐答案

String s不应与==或!=进行比较，除非您想知道它们是否是相同的字符串且占用相同的内存位置.改为使用equals().

Strings should not be compared with == or != unless you want to know if they are the same string occupying the same memory location. Use equals() instead.

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