ConcurrentHashMap的使用

 

 

http://blog.csdn.net/gjt19910817/article/details/47353909

 

Long oldValue, newValue;
    while(true) {
        oldValue = wordCounts.get(word);
        if(oldValue == null) {
            // Add the word firstly, initial the value as 1
            newValue = 1L;
            if(wordCounts.putIfAbsent(word, newValue) == null) {
                break;
            }
        }else{
            newValue = oldValue + 1;
            if(wordCounts.replace(word, oldValue, newValue)) {
                break;
            }
        }
    }