Java -- 集合List

//ArrayList: List的主要实现类
/**
* 增：add(Object obj)
* 删：remove(int index)
* 改：set(int index,Object ele)
* 查：get(int index)
* 插：add(int index,Object ele)
* 长：size()
*/

// @Test
public void Test1(){
List list = new ArrayList();
list.add(123);
list.add(456);
list.add(new String("AA"));
list.add(new String("GG"));
System.out.println(list);

list.add(0, 666);
System.out.println(list);

Object o1 = list.get(1);
System.out.println(o1);

Object o2 = list.remove(2);
System.out.println(o2);

list.set(1, 222);
System.out.println(list);


}

@Test
public void Test2(){
List list = new ArrayList();
list.add(123);
list.add(456);
list.add(new String("AA"));
list.add(new String("GG"));
System.out.println(list.indexOf(456));//如果有返回1，否则返回-1
System.out.println(list.lastIndexOf(456));
System.out.println(list.indexOf(123) == list.lastIndexOf(123));
System.out.println(list.indexOf(444));

List list1 = list.subList(0, 2);//[5,7]相当于包含5不包含7 5<=x<7
System.out.println(list1);// [123, 456]


}