对于我的任务,我们需要创建一个字符串哈希表,我已经使用整数创建了一个,它运行良好,但我现在遇到了麻烦。
我一直在获取java.lang.NumberFormatExceptions
我输入的字符串,但我不确定为什么会这样。这是我用于 HashTable 类的代码;
public class HashTable {
private SortedList[] hashArray;
private int arraySize;
public HashTable(int size) {
arraySize = size;
hashArray = new SortedList[arraySize];
for(int i = 0; i < arraySize; i++) {
hashArray[i] = new SortedList();
}
} // END HashTable()
public void displayTable() {
for(int i = 0; i < arraySize; i++) {
System.out.print(i + ". ");
hashArray[i].displayList();
}
} // END displayTable()
public int hash(String key) {
int hashkey = Integer.parseInt(key);
return hashkey % arraySize;
} // END hash()
public void insert(Link link) {
String key = link.getKey();
int hashVal = hash(key);
hashArray[hashVal].insert(link);
} // END insert()
public void delete(String key) {
int hashVal = hash(key);
hashArray[hashVal].delete(key);
} // END delete()
} // END HashTable
这是列表的代码:
public class SortedList {
private Link first;
public void SortedList() {
first = null;
} //END SortedList()
public void insert(Link link) {
String key = link.getKey();
Link previous = null;
Link current = first;
while(current != null && key.compareTo(current.getKey()) > 0) {
previous = current;
current = current.getNext();
}
if(previous == null) {
first = link;
} else {
previous.setNext(link);
link.setNext(current);
}
} // END insert()
public void delete(String key) {
Link previous = null;
Link current = first;
while(current != null && !key.equals(current.getKey())) {
previous = current;
current = current.getNext();
}
if(previous == null) {
first = first.getNext();
} else {
previous.setNext(current.getNext());
}
} // END delete()
public Link find(String key) {
Link current = first;
while(current != null && current.getKey().compareTo(key) <= 0) {
if(current.getKey().equals(key)) {
return current;
}
current = current.getNext();
}
return null;
} // END find()
public void displayList() {
System.out.print("List (first -> last): ");
Link current = first;
while(current != null) {
current.displayLink();
current = current.getNext();
}
System.out.println();
} // END displayList()
} //END SortedList()
Link 类只是一个基本类,我在线上抛出错误:
int hashkey = Integer.parseInt(key);
在哈希函数中,在我的 HashTable 类中。
编辑:据我所知,我被要求做,我需要将字符串转换为整数,然后执行散列函数以获取其位置的索引。