Quickly grasp the common use of ArrayList and Vector classes in the Java container
- 2020-04-01 04:23:17
- OfStack
ArrayList class
Instantiation of List collection:
List<String> l = new ArrayList<String>(); //The List collection is instantiated using the ArrayList class
List<String> l2 = new LinkedList<String>(); //Use the LinkedList class to instantiate the List collection
Common methods of ArrayList:
The add (int index, Object obj); AddAll (int, Collection coll); Remove (int index); Set (int index, Object obj); Get (int index); IndexOf (Object obj); The lastIndexOf (Object obj); ListIterator (); ListIterator (int index);
Example of ArrayList: an implementation that creates an empty ArrayList object, adds elements to it, and then outputs all elements.
<%@ page import="java.util.*" %>
<%
List<String> list = new ArrayList<String>();
for(int i=0;i<3;i++) {
list.add(new String(" fuwa " + i));
}
list.add(1, " After adding fuwa ");
//Output all elements
Iterator<String> it = list.iterator();
while(it.hasNext()) {
out.println(it.next());
}
%>
The output result is:
fuwa 0 After adding fuwa fuwa 1 fuwa 2
The usage of the LinkedList class is similar to that of the ArrayList class.
The Vector class
Common methods of Vector class:
Instance of Vector class: implement creating an empty Vector object, adding elements to it, and then outputting all elements.
<%@ page import="java.util.*" %>
<%
Vector v = new Vector(); //Create an empty Vector object
for(int i=0;i<3;i++) {
v.add(new String(" fuwa " + i));
}
v.remove(1); //Removes an element with an index position of 1
//Display all elements
for(int i=0;i<v.size();i++) {
out.println(v.indexOf(v.elementAt(i))+": "+v.elementAt(i));
}
%>
The display result is:
0: fuwa 0 1: fuwa 2