Java列表接口

列表接口是Collection的子接口。它包含用于插入和删除元素的基于索引的方法。它是ListIterator接口的工厂。

列表接口声明

public interface List<E> extends Collection<E>

Java List接口的方法

Java列表示例

import java.util.*;
public class ListExample{
public static void main(String args[]){
List<String> al=new ArrayList<String>();
al.add("Amit");
al.add("Vijay");
al.add("Kumar");
al.add(1, "Sachin");
System.out.println("An element at 2nd position: "+al.get(2));
for(String s:al){
 System.out.println(s);
}
}
}

输出：

An element at 2nd position: Vijay
Amit
Sachin
Vijay
Kumar

Java ListIterator接口

ListIterator接口用于在后退和前进方向上遍历元素。

ListIterator接口声明

public interface ListIterator<E> extends Iterator<E>

Java ListIterator接口的方法：

ListIterator接口示例

import java.util.*;
public class ListIteratorExample1{
public static void main(String args[]){
List<String> al=new ArrayList<String>();  
		al.add("Amit");  
		al.add("Vijay");  
		al.add("Kumar");  
		al.add(1, "Sachin");  
		ListIterator<String> itr=al.listIterator();  
		System.out.println("Traversing elements in forward direction");  
		while(itr.hasNext()){  
			
		System.out.println("index:"+itr.nextIndex()+" value:"+itr.next());  
		}  
		System.out.println("Traversing elements in backward direction");  
		while(itr.hasPrevious()){  
		
		System.out.println("index:"+itr.previousIndex()+" value:"+itr.previous());  
		}  
}
}

输出：

Traversing elements in forward direction
index:0 value:Amit
index:1 value:Sachin
index:2 value:Vijay
index:3 value:Kumar
Traversing elements in backward direction
index:3 value:Kumar
index:2 value:Vijay
index:1 value:Sachin
index:0 value:Amit

ListIterator接口示例：书籍

import java.util.*;
class Book {
int id;
String name, author, publisher;
int quantity;
public Book(int id, String name, String author, String publisher, int quantity) {
	this.id = id;
	this.name = name;
	this.author = author;
	this.publisher = publisher;
	this.quantity = quantity;
}
}
public class ListIteratorExample2 {
public static void main(String[] args) {
	//Creating list of Books
	List<Book> list=new ArrayList<Book>();
	//Creating Books
	Book b1=new Book(101, "Let us C", "Yashwant Kanetkar", "BPB", 8);
	Book b2=new Book(102, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
	Book b3=new Book(103, "Operating System", "Galvin", "Wiley", 6);
	//Adding Books to list
	list.add(b1);
	list.add(b2);
	list.add(b3);
	//Traversing list
	for(Book b:list){
	System.out.println(b.id+" "+b.name+" "+b.author+" "+b.publisher+" "+b.quantity);
	}
}
}

输出：

101 Let us C Yashwant Kanetkar BPB 8
102 Data Communications & Networking Forouzan Mc Graw Hill 4
103 Operating System Galvin Wiley 6