java 交集性能测试

import java.util.BitSet;
import java.util.HashSet;
import java.util.Random;
import java.util.Set;

public class BitSetTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		BitSet bm = new BitSet();
		int randomVal = 1000000;
		for (int i = 0; i < 1000000; i++) {
			bm.set(new Random().nextInt(randomVal));
		}

		BitSet bm2 = new BitSet();
		for (int i = 0; i < 1000000; i++) {
			bm2.set(new Random().nextInt(randomVal));
		}

		long s = System.currentTimeMillis();

		bm2.and(bm);

		System.out.println(System.currentTimeMillis() - s);
	}

}

 

import java.util.BitSet;
import java.util.HashSet;
import java.util.Random;
import java.util.Set;

 public class SetTest {  
  
    /**  
     * @param args  
     */  
    public static void main(String[] args) {  
    	HashSet bm=new HashSet(); 
        int randomVal = 1000000;
        for(int i=0;i<1000000;i++){
        	bm.add(new Random().nextInt(randomVal));
        }
        Set bm2=new HashSet(); 
        for(int i=0;i<1000000;i++){
        	bm2.add(new Random().nextInt(randomVal));
        }
        
        long s = System.currentTimeMillis();
        
        bm.retainAll(bm2);
        
		System.out.println(bm.size());
        

        System.out.println(bm2.size());
        
        System.out.println(System.currentTimeMillis()-s);
        
    }  
  
}