负载因子是和扩容机制有关的,意思是如果当前容器的容量,达到了我们设定的最大值,就要开始执行扩容操作。举个例子来解释,避免小白听不懂: 比如说当前的容器容量是16,负载因子是0.75,16*0.75=12,也就是说,当容量达到了12的时候就会进行扩容操作。 扩容的机制是当前容量大小的 2倍 他的作用很简单,相当于是一个扩...
当哈希表中条目数超出了当前容量*加载因子(其实就是HashMap的实际容量)时,则对该哈希表进行rehash操作,将哈希表扩充至两倍的桶数。 Java中默认初始容量为16,加载因子为0.75。 staticfinalintDEFAULT_INITIAL_CAPACITY =1<<4;//aka 16staticfinalfloatDEFAULT_LOAD_FACTOR =0.75f; 1)loadFactor加载因子 定义:loadFa...
上一篇我们讨论了HashMap的扩容操作, 提到扩容操作发生在table的初始化或者table大小超过threshold后,而这两个条件的触发基本上就发生在put操作中。 本篇我们就来聊聊HashMap的put操作。 本文的源码基于 jdk8 版本. put方法 HashMap 实现了Map接口, 因此必须要实现put方法: public V put(K key, V value) { ret...
复制 # coding=utf-8classMyHash(object):def__init__(self,length=10):self.length=length self.items=[[]foriinrange(self.length)]defhash(self,key):"""计算该key在items哪个list中,针对不同类型的key需重新实现"""returnkey%self.length defequals(self,key1,key2):"""比较两个key是否相等,针对不...
HashMap{1=Python, 2=Java, 3=JS} Java is present on the list. In the above example, we have created a hashmap namedlanguages. Notice the expressions, languages.containsValue("Java")// returns true Here, the specified valueJavais present in the mapping ({2=Java}). Hence, thecontainsVal...
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出品| 小林coding(ID:CodingLin ) 已获得原公众号的授权转载 今天分享一位同学Java快手后端面经,问的问题不难,主要都是基础八股,Java 集合+Java 线程池+mysql索引+redis+算法。 面试整体感受挺好的, 面试官人很好,都是常见八股文,不会的会给出解释和引导,体验很好,看到反转链表(算法)感觉很开心。
Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use. But these can also be overused and fall into some common pitfalls. To get a better understandi...
In favor of hardcoding: public class Message { public Message() { } public String getTagName( int tagNumber) { switch( tagNumber) { case 1: return "tag1Name"; case 2: return "tag2Name"; case 3: return "tag3Name"; default return null; } } } When you put everything in the ...
ServerClientServerClientRequest dataRetrieve data from hashmapReturn data Remember, the hashmap is a powerful tool in your web development toolkit. Happy coding! References [jQuery API Documentation]( [Hash Map - Wikipedia](