analysis 标签

基本方法

使用由 toString() 方法提供的默认的转换显示类集的内容，toString() 方法是从 AbstractCollection() 继承下来的。对于例子来说足够，但是通常情况下会重写此方法。

 public class ArrayListTest1 {
   public static void main(String[] args) {
     ArrayList arrayList = new ArrayList();
     arrayList.add("hello");
     arrayList.add("world");
     arrayList.add("world");
     arrayList.add("welcome");
 
     String s1 = (String) arrayList.get(0);
     String s2 = (String) arrayList.get(1);
     String s3 = (String) arrayList.get(2);
     String s4 = (String) arrayList.get(3);
 
     System.out.println(s1);
     System.out.println(s2);
     System.out.println(s3);
     System.out.println(s4);
 
     System.out.println("-------------");
     for (int i = 0; i < arrayList.size(); i++) {
       System.out.println(arrayList.get(i));
     }
 
     // arrayList.clear();
     // System.out.println(arrayList.size());
     // System.out.println(arrayList.isEmpty());
 
     arrayList.remove(0);
 
     System.out.println("-------------");
     for (int i = 0; i < arrayList.size(); i++) {
       System.out.println(arrayList.get(i));
     }
 
     arrayList.remove("welcome");
     System.out.println("-------------");
     for (int i = 0; i < arrayList.size(); i++) {
       System.out.println(arrayList.get(i));
     }
 
     System.out.println("-----------------");
 
     arrayList.add("aaa");
     arrayList.add("bbb");
 
     System.out.println(arrayList.indexOf("world"));
     System.out.println(arrayList.lastIndexOf("world"));
     System.out.println(arrayList.indexOf("aaa"));
   }
 }

Terwer...大约 5 分钟