arraylistexample.java

java 完全探索的随书源码

import java.util.ArrayList;

public class ArrayListExample {

  public void doExample() {
    ArrayList myList = new ArrayList(5);  // set initial array capacity to 5
    // load the list with integers 0-4 wrapped in Integer
    for ( int i=0; i<5; i++) {
      myList.add( new Integer(i) );
    }
    System.out.println( "List contains " + myList.size() + " elements" );

    // locate a specific object in the list
    Integer int2 = new Integer(2);
    System.out.println( "List contains Integer(2): " +
      myList.contains(int2) );
    System.out.println( "Integer(2) is at index " + myList.indexOf(int2) );

    // replace an object and then locate it by index
    myList.set(2, new Integer(99));
    System.out.println( "Get element at index 2: " + myList.get(2) );

    // add 5 more elements - capacity will grow automatically
    for ( int i=5; i<10; i++) {
      // add by specifying the index
      myList.add( i, new Integer(i) );
    }

    // add 5 more elements, but increase the capacity first
    myList.ensureCapacity(15);
    for ( int i=10; i<15; i++) {
      myList.add( new Integer(i) );
    }

    // take the last 5 elements back out and reduce the capacity
    myList.subList(10,15).clear();
    myList.trimToSize();

    // create another list and copy it into the original one
    ArrayList otherList = new ArrayList();
    otherList.add( new String("otherList 1") );
    otherList.add( new String("otherList 2") );
    myList.add(7,otherList);

    // display the list elements
    System.out.println(myList);
  }

  public static void main( String args[] ) {
    new ArrayListExample().doExample();
  }

}