java map按照value值来比较大小并且返回最终结果

古城微笑少年丶 2022-09-25 07:16 53阅读 0赞

原文：[java map按照value值来比较大小并且返回最终结果][java map_value]

源代码下载地址： [http://www.zuidaima.com/share/1830834176347136.htm][java map_value]

package com.zuidaima.util;
    
    import java.util.Comparator;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.TreeMap;
    
    public class ValueComparator implements Comparator<Long> {
    
    	Map<Long, Double> base;
    
    	public ValueComparator(Map<Long, Double> base) {
    		this.base = base;
    	}
    
    	public int compare(Long a, Long b) {
    		if (base.get(a).doubleValue() >= base.get(b).doubleValue()) {
    			return -1;
    		} else {
    			return 1;
    		}
    	}
    
    	public static <K, V extends Comparable<V>> Map<K, V> sortByValues(
    			final Map<K, V> map) {
    		Comparator<K> valueComparator = new Comparator<K>() {
    			public int compare(K k1, K k2) {
    				int compare = map.get(k2).compareTo(map.get(k1));
    				if (compare == 0)
    					return 1;
    				else
    					return compare;
    			}
    		};
    		Map<K, V> sortedByValues = new TreeMap<K, V>(valueComparator);
    		sortedByValues.putAll(map);
    		return sortedByValues;
    	}
    
    	public static void main(String[] args) {
    		HashMap<Long, Double> map = new HashMap<Long, Double>();
    		map.put(1l, 99.5);
    		map.put(2l, 67.2);
    		map.put(3l, 67.5);
    		map.put(4l, 67.6);
    
    		ValueComparator bvc = new ValueComparator(map);
    		TreeMap<Long, Double> sorted_map = new TreeMap<Long, Double>(bvc);
    
    		System.out.println("unsorted map: " + map);
    
    		sorted_map.putAll(map);
    
    		System.out.println("results: " + sorted_map);
    
    		Map<Long, Double> sorted_map2 = sortByValues(map);
    		
    		System.out.println("results2: " + sorted_map2);
    	}
    }

输出结果：

unsorted map: \{1=99.5, 2=67.2, 3=67.5, 4=67.6\}  
results: \{1=99.5, 4=67.6, 3=67.5, 2=67.2\}  
results2: \{1=99.5, 4=67.6, 3=67.5, 2=67.2\}

通过key比较大小的原理类似，大家改写下就好了。enjoy it。

[java map_value]: http://www.zuidaima.com/share/1830834176347136.htm