Java中ArrayList的使用

//创建ArrayList

ArrayList arr  = new ArrayList();

//ArrayList添加数据

arr.add("123");

arr.add("234");

arr.add("345");

arr.add("456");

arr.add("567");

arr.add("678");

//ArrayList转化为数组

Object[]  strArr =  arr.toArray();

System.out.println(strArr.length);

System.out.println("-----------------------");

for (int i=0;i<strArr.length;i++){

System.out.println(strArr[i]);

}

//获取ArrayList的迭代器iterator

Iterator iterator  = arr.iterator();

System.out.println("-----------------------");

while (iterator.hasNext()){

System.out.println(iterator.next());

}

System.out.println("-----------------------");

//ArrayList中的移除数据

boolean result  = arr.remove("123");

System.out.println(result);

for (int i=0;i<arr.size();i++){

System.out.println(arr.get(i));

}

System.out.println("-----------------------");

//ArrayList插入数据

arr.set(0,"123");

for (int i=0;i<arr.size();i++){

System.out.println(arr.get(i));

}

System.out.println("-----------------------");

ArrayList arr2 = new ArrayList(3);

arr2.add("abc");

arr2.add("bcd");

arr2.add("cde");

//ArrayList添加一个集合

arr.addAll(arr2);

for (int i=0;i<arr.size();i++){

System.out.println(arr.get(i));

}

System.out.println("-----------------------");

//获取ArrayList的元素个数

int size = arr.size();

//判断ArrayList是否为空

boolean result1 = arr.isEmpty();

System.out.println(size);

System.out.println(result1);

System.out.println("-----------------------");

//Arr判断ArrayList是否包含abc

boolean result3 = arr.contains("abc");

System.out.println(result3);

System.out.println(arr.containsAll(arr2));

//获取ArrayList中的对象的索引

int index = arr.indexOf("abc");

System.out.println(index);

//克隆ArrayList

Object ob = arr.clone();

System.out.println(ob);

System.out.println("-----------------------");

//获取ArrayList中对应索引的对象

Object obj = arr.get(3);

System.out.println(obj);

System.out.println("-----------------------");

//清除ArrayList中的所有元素

arr2.clear();

System.out.println(arr2);

System.out.println("-----------------------");