自制数据结构（容器）-java开发用的最多的ArrayList和HashMap

 

public class MyArrayList<E> {  
		    private int capacity = 10;  
		    private int size = 0;  
		    private E[] values = null;  
		  
		    @SuppressWarnings("unchecked")  
		    public MyArrayList() {  
		        values = (E[]) new Object[capacity];  
		    }  
		  
		    @SuppressWarnings("unchecked")  
		    public MyArrayList(int capacity) {  
		        this.capacity = capacity;  
		        values = (E[]) new Object[this.capacity];  
		    }  
		  
		    public void put(E e) {  
		        if (e == null) {  
		            throw new RuntimeException("The value should not be null.");  
		        }  
		        if (size >= capacity) {  
		            enlargeCapacity();  
		        }  
		        values[size] = e;  
		        size++;  
		    }  
		  
		    public E get(int index) {  
		        if (index >= size) {  
		            throw new RuntimeException("The index:" + index + " is out of band.");  
		        }  
		        return values[index];  
		    }  
		  
		    public void remove(int index) {  
		        if (index >= size) {  
		            throw new RuntimeException("The index:" + index + " is out of band.");  
		        }  
		        for (int i = index; i < size - 1; i++) {  
		            values[i] = values[i + 1];  
		        }  
		        values[size - 1] = null;  
		        size--;  
		    }  
		  
		    @SuppressWarnings("unchecked")  
		    private void enlargeCapacity() {  
		        capacity = capacity * 2;  
		        E[] tmpValues = (E[]) new Object[capacity];  
		        System.arraycopy(values, 0, tmpValues, 0, size);  
		        values = tmpValues;  
		    }  
		  
		    public String toString() {  
		        StringBuilder sb = new StringBuilder();  
		        sb.append("[");  
		        for (int i = 0; i < size; i++) {  
		            sb.append(values[i]).append(",");  
		        }  
		        if (size > 0) {  
		            sb.deleteCharAt(sb.length() - 1);  
		        }  
		        sb.append("]");  
		        return sb.toString();  
		    }    
		    /** 
		     * @param args 
		     */  
		    public static void main(String[] args) {  
		        MyArrayList<Integer> myList = new MyArrayList<Integer>();  
		        for(int i=0;i<1000;i++){
		        	myList.put(i);  
		        }
		        System.out.println(myList.toString());  
		    }  
 

	}