HashMap,根据key,value排序和HashMap在声明时初始化

/声明的时候初始化
HashMap hashMap = new HashMap(){
{
put("a", 1);
put("b", 3);
put("c", 2);
}
};
//sorted by value
ArrayList<Map.Entry> l = new ArrayList<Map.Entry>(hashMap.entrySet());
Collections.sort(l, new Comparator<Map.Entry>() {
public int compare(Map.Entry o1, Map.Entry o2) {
return o1.getValue().compareTo(o2.getValue()) ;
}
});
for(Map.Entry e : l) {
System.out.println(e.getKey() + "::::" + e.getValue());
}

//sorted by key
l = new ArrayList<Map.Entry>(hashMap.entrySet());
Collections.sort(l, new Comparator<Map.Entry>() {
public int compare(Map.Entry o1, Map.Entry o2) {
return o1.getKey().compareTo(o2.getKey());
}
});
for(Map.Entry e : l) {
System.out.println(e.getKey() + "::::" + e.getValue());
}
//sorted by key,利用treeMap的特性
TreeMap treeMap= new TreeMap(hashMap);
for(Iterator iterator=treeMap.keySet().iterator();iterator.hasNext();) {
String temp=iterator.next();
System.out.println(temp + "::::" + treeMap.get(temp));
}

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