compareduplicate.java

用于比较两个list中的字符是否有重复的,如果有则输出重复的内容.

package test.structure;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class CompareDuplicate {

	
	
	
	public static void main(String[] args) {
		;
		System.out.println(checkTheSameData((List)getListArray()));
		//System.out.println(havaSameElement(data));
		
	}
	
	
	private String[] getStringArray() {
		String[] data = { "1", "2", "3", "2", "4", "3" };
		return data;
	}
	
	private static List getListArray() {
		List data =new ArrayList();
		data.add("1");
		data.add("5");
		data.add("5");
		data.add("4");
		data.add("8");
		data.add("19");
		data.add("2");		
		return data;
	}
	
	
	 /** 
     *   check   the   list   have   same   element 
     *   @param   list   List 
     *   @return   have   same   element   result 
     */ 
   private static boolean checkTheSameData(List list) {
		Iterator it = list.iterator();
		Map map = new HashMap();
		String element = null;
		while (it.hasNext()) {
			element = (String) it.next();
			if (null != map.get(element)) {
				System.out.println(element);
				return true;
			} else {
				map.put(element, element);
				
			}
		}
		map.keySet();
		return false;

	} 

	
	
	public static boolean havaSameElement(String[] a) {
		Set<String> s = new HashSet<String>();
		boolean b = false;
		for (int i = 0; i < a.length; i++) {
			if ((b = s.add(a[i])) == false) {//return ture,if hashset add elements in failure then it includes same elements.
				System.out.println(a[i]);
				b = true;
				break;
			}
		}
		return b;
	}
}