[转载]Java 根据 HashMap 的 value 进行排序
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转载:http://www.oschina.net/code/snippet_12_546?from=rss
package net.oschina.tester;import java.util.*;/** * 根据 HashMap 的 value 进行排序 * @author Winter Lau * @date 2009-11-24 下午01:35:37 */public class SortByValueDemo {public static void main(String[] args) {HashMap<String, Integer> datas = new HashMap<String, Integer>(){{put("Winter Lau", 100);put("Yier", 150);put("Nothing", 30);put("Zolo", 330);}};ByValueComparator bvc = new ByValueComparator(datas);//第一种方法TreeMap<String, Integer> sorted_map = new TreeMap<String, Integer>(bvc);sorted_map.putAll(datas);for(String name : sorted_map.keySet()){System.out.printf("%s -> %d\n", name, datas.get(name));}//第二种方法List<String> keys = new ArrayList<String>(datas.keySet());Collections.sort(keys, bvc);for(String key : keys) {System.out.printf("%s -> %d\n", key, datas.get(key));}}static class ByValueComparator implements Comparator<String> {HashMap<String, Integer> base_map;public ByValueComparator(HashMap<String, Integer> base_map) {this.base_map = base_map;}public int compare(String arg0, String arg1) {if (!base_map.containsKey(arg0) || !base_map.containsKey(arg1)) {return 0;}if (base_map.get(arg0) < base_map.get(arg1)) {return 1;} else if (base_map.get(arg0) == base_map.get(arg1)) {return 0;} else {return -1;}}}}??
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