• private ArrayList <String> notes=new ArrayList<String>();
  • 用来存放String的ArrayList
  • 容器类有两个类型
    • 容器的类型
    • 元素的类型
import java.util.ArrayList;

public class Notebook {
	private ArrayList <String> notes=new ArrayList<String>();
	public void add(String s) {
		notes.add(s);
	}
	
	public void add(String s,int location) {
		notes.add(location,s);
	}
	
	public int getSize() {
		return notes.size();
	}
	
	public String getnote(int index) {
		return notes.get(index);
	}
	
	public void removeNote(int index) {
		notes.remove(index);
	}
	
	public String[] list() {
		String[]a =new String[notes.size()];
		notes.toArray(a);
		return a;
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Notebook nb=new Notebook();
		nb.add("first");
		nb.add("second");
		nb.add("third",1);
		System.out.println(nb.getSize());
		System.out.println(nb.getnote(0));
		System.out.println(nb.getnote(1));
		nb.removeNote(1);
		String[] a=nb.list();
		for (String s:a) {
			System.out.println(s);
		}
	}

}