模拟ArrayList(初级)

这里先作为了解容器的起步，模拟一下ArrayList，后面在容器中会有更多的内容

package cn.itcast.java.test;  /**  * 模拟ArrayList  * @author Administrator  *  */  public class MyArrayList {      private Object[] value;      private int size;      public MyArrayList(){          //value = new Object[10];          this(10);      }      public MyArrayList(int capacity){          value = new Object[capacity];      }      /*      * 返回容器的大小      */      public int size(){          return size;      }      /*      * 判断容器是否为空      */      public boolean isEmpty(){          return value.length == 0;      }      /*      * 添加元素      */      public void add(Object obj){          value[size] = obj;          size++;          if(size>=value.length){              //扩容              int newCapacity = value.length*2+2;              Object[] newValue = new Object[newCapacity];              //数组拷贝              for(int i=0;i<value.length;i++){                  newValue[i] = value[i];              }              value = newValue;          }      }      /*      * 根据索引返回元素      */      public Object get(int index){          if(index<0||index>=value.length){              try {                  throw new Exception();              } catch (Exception e) {                  e.printStackTrace();              }          }          return value[index];      }      public static void main(String[] args) {          MyArrayList list = new MyArrayList();          list.add("aa");          list.add(new Person("Gao"));          list.add(11);          System.out.println(list.get(0));          System.out.println(list.get(1));          System.out.println(list.size());          System.out.println(list.isEmpty());      }  }  

具体的尚学堂ArrayList实现过程点击此处