在網上搜了下，發現沒有關於陣列實現迭代的相關文章，所以自己寫了下。

主要是模仿的一個Arraylist 實現的主要的功能！

程式碼如下：

首先建個介面：

package com.list;

public interface List<T> extends Iterable<T>{

	 void add(T e);
	 void remove(T t);
	 void removeAt(int index);
	 int size();
	 void clear();
	 int indexOf(Object object);
	 void set(T e,int index);
}
 

package com.list.impl;

import java.util.Iterator;

import com.list.List;

public class ArrayList<T> implements List<T> {

	
	Object [] objects=new Object[0];
	
	public void add(T t) {
		// TODO Auto-generated method stub
		Object [] tmp=new Object[objects.length+1];
		tmp[tmp.length-1]=t;
		System.arraycopy(objects, 0, tmp, 0, objects.length);
		objects=tmp;
	}

	@Override
	public void remove(T t) {
		// TODO Auto-generated method stub
		for(int i=0;i<objects.length;i++){
			if(objects[i].equals(t)){
				if(i>0){
					Object object[]=new Object[objects.length-1];
					System.arraycopy(objects, 0, object, 0, i);
					System.arraycopy(objects, i+1, object, i, objects.length-i-1);
					objects=object;
					break;
				}
			}
		}
		
	}

	@Override
	public void removeAt(int index) {
		// TODO Auto-generated method stub
		if(index>=0){
			Object object[]=new Object[objects.length-1];
			System.arraycopy(objects, 0, object, 0, index);
			System.arraycopy(objects, index+1, object, index, objects.length-index-1);
			objects=object;
		}
		
	}

	@Override
	public int size() {
		// TODO Auto-generated method stub
		return objects.length;
	}

	@Override
	public void clear() {
		// TODO Auto-generated method stub
		this.objects=new Object[0];
		
	}

	@Override
	public int indexOf(Object object) {
		// TODO Auto-generated method stub
		for(int i=0;i<objects.length;i++){
			if(objects[i].equals(object)){
				return i;
			}
		}
		return -1;
	}

	@Override
	public void set(T e, int index) {
		// TODO Auto-generated method stub
		objects[index]=e;
		
	}

	@Override
	public Iterator<T> iterator() {
		// TODO Auto-generated method stub
		Iterator<T> iterator=new Iterator<T>() {
			int index=0;
			boolean hasNext=true;
			@Override
			public boolean hasNext() {
				// TODO Auto-generated method stub
				return hasNext;
			}

			@Override
			public T next() {
				
				// TODO Auto-generated method stub
				if(index++<objects.length-1){
					hasNext=true;
					return (T)objects[index-1];
				}
				else {
					hasNext=false;
					return (T)objects[objects.length-1];
				}
			}

			@Override
			public void remove() {
				// TODO Auto-generated method stub
				objects=new Object[0];
			}
			
		};
		
		return iterator;
	}

}
 

這個介面有 這幾個方法
hasNext()
next()
remove()

hasNext 是否有下一條資料

next 獲取下一個物件

remove 移除全部

我們在類中實現iterator這個介面後，重寫public Iterator<T> iterator()  這個方法

Iterator<T> iterator=new Iterator<T>() {
			int index=0;
			boolean hasNext=true;
			@Override
			public boolean hasNext() {
				// TODO Auto-generated method stub
				return hasNext;
			}

			@Override
			public T next() {
				
				// TODO Auto-generated method stub
				if(index++<objects.length-1){//判斷是否超過陣列
					hasNext=true;
					return (T)objects[index-1];
				}
				else {
					hasNext=false;
					return (T)objects[objects.length-1];//將陣列物件轉換成泛型
				}
			}

			@Override
			public void remove() {
				// TODO Auto-generated method stub
				objects=new Object[0];//這是陣列物件
			}
			
		};
		
		return iterator;
 

移除方法，官方的JDK原始碼中，也是用

System.arraycopy(objects, 0, object, 0, index);

下面是我的使用和測試程式碼：

package com.test;

import com.list.*;
import com.list.impl.ArrayList;
public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		List<Object> list=new ArrayList<Object>();
		String str="張三";
		list.add(1);
		list.add(2);
		list.add(3);
		list.add(new Object());
		list.add(new Object());
		list.add(new Object());
		list.add(str);
		list.add("hello");
		list.remove(str);
		list.remove(str);
		list.removeAt(0);
		for (Object object : list) {
			System.out.println(object);
		}
		System.out.println(list.size());
	}

}

多看JDK原始碼，是有收穫的！~