浅谈java中的TreeMap 排序与TreeSet 排序

package com;import java.util.Comparator;import java.util.TreeMap;public class Test5 {	/**	 * @param args	 */	public static void main(String[] args) {		// TODO Auto-generated method stub		TreeMap<String, String> tree = new TreeMap<String, String>(				new Comparator<Object>() {					@Override					public int compare(Object o1, Object o2) {						// TODO Auto-generated method stub						if(o1 == null || o2 == null){							return 0;						}												return o1.toString().compareTo(o2.toString());					}				}		);								tree.put("k", "1");		tree.put("ba", "2");		tree.put("z", "3");		tree.put("d", "4");		tree.put("e", "5");		tree.put("an", "6");		tree.put("c", "7");				for(String str : tree.keySet()){			System.out.println(str);		}	}}

package com;import java.util.Comparator;import java.util.TreeSet;public class Test6 {	/**	 * @param args	 */	public static void main(String[] args) {		// TODO Auto-generated method stub		TreeSet<Object> tree = new TreeSet<Object>(new Comparator<Object>() {			@Override			public int compare(Object o1, Object o2) {				// TODO Auto-generated method stub				if(o1 == null || o2 == null){					return 0;				}								if(Integer.parseInt(o1.toString()) > Integer.parseInt(o2.toString())){					return -1;				}else if(Integer.parseInt(o1.toString()) < Integer.parseInt(o2.toString())){					return 1;				}else{					return 0;				}			}		});				tree.add(4);		tree.add(5);		tree.add(6);		tree.add(1);		tree.add(2);		tree.add(3);		for(Object o : tree){			System.out.println(o);		}	}}