java实现链表指定值得删除，查找第二部分代码

package com.liu.Link;

public class LinkList1 {
private Link first;
public LinkList1()
{
first = null;
}

public void insertFirst(int id,double dd)
{
Link newLink = new Link(id,dd);
newLink.next = first;
first = newLink;
}

public Link find(int key)
{
Link current = first;
while(current.iData!=key)
{
if(current.next == null)
return null;
else
current = current.next;
}
return current;
}

public Link delete(int key)
{
Link current = first;
Link previous = first;
while(current.iData != key)
{
if(current.next == null)
return null;
else
{
previous = current;
current = current.next;
}
}
//情况1，删除的数字就是first指针指向的位置
if(current == first)
{
first = first.next;
}
//情况2，删除的数字是中间位置
else
{
previous.next = current.next;
}
//current就是previous.next
return current;
}

public void displayList()
{
System.out.print("List (first-->last):");
Link current = first;
while(current != null)
{
current.displayLink();
current = current.next;
}
System.out.println("");
}
}

//链表数据类
class Link
{
public int iData;
public double dData;
public Link next;

public Link(int id,double dd)
{
iData = id;
dData = dd;
}

public void displayLink()
{
System.out.print("{"+ iData +", "+ dData +"}");
}

}

class LinkListApp
{
public static void main(String args[])
{
LinkList1 theList = new LinkList1();
theList.insertFirst(22, 2.99);
theList.insertFirst(44, 4.99);
theList.insertFirst(66, 6.99);
theList.insertFirst(88, 8.99);
theList.insertFirst(33, 3.99);

theList.displayList();

Link f = theList.find(44);
if(f!=null)
System.out.println("Fount link with key "+f.iData);
else
System.out.println("can't find link");

Link d = theList.delete(66);
if( d != null )
System.out.println("Deleted link with key " + d.iData);
else
System.out.println("Can't delete link");

theList.displayList();
}
}