packagecom.light.swordimportjava.util.*importjava.util.concurrent.atomic.AtomicInteger/** * @author: Jack * 2020-02-21 13:52 */funmain(){val map=HashMap<Int,Int>()val atomicInt=AtomicInteger(0)for(iin0..9){Threa
package java.util; import java.io.*; public class HashMap<K, V> extends AbstractMap<K, V> implements Map<K, V>, Cloneable, Serializable { // 默认的初始容量(容量为HashMap中槽的数目)是16,且实际容量必须是2的整数次幂。 static final int DEFAULT_INITIAL_CAPACITY = 16; // 最大容量(必须是...
1. 使用 Iterator 遍历 HashMap EntrySet packagecom.java.tutorials.iterations;importjava.util.HashMap;importjava.util.Iterator;importjava.util.Map;importjava.util.Map.Entry;/** *在 Java 中遍历 HashMap 的5种最佳方式 *@authorRamesh Fadatare * */publicclassIterateHashMapExample{publicstaticvoidmain(...
而Java 8的ConcurrentHashMap,它与Java 7的实现差别较大。完全放弃了段的设计,而是变回与HashMap相似的设计,使用buckets数组与分离链接法(同样会在超过阈值时树化,对于构造红黑树的逻辑与HashMap差别不大,只不过需要额外使用CAS来保证线程安全),锁的粒度也被细分到每个数组元素(因为HashMap在Java 8中也实现了不少...
package ca.bazlur; import org.openjdk.jmh.annotations.Benchmark; import org.openjdk.jmh.annotations.*; import org.openjdk.jmh.infra.Blackhole; import java.util.HashMap; import java.util.Map; import java.util.concurrent.TimeUnit; @State(Scope.Benchmark) ...
Returns the number of key-value mappings in this map. Collection<V>values() Returns aCollectionview of the values contained in this map. Methods inherited from class java.util.AbstractMap equals,hashCode,toString Methods inherited from class java.lang.Object ...
package map; import java.util.Collection; import java.util.HashMap; import java.util.Set; public class HashMapDemo { public static void main(String[] args) { HashMap<String, String> map = new HashMap<String, String>(); // 键不能重复,值可以重复 map.put("san", "张三"); map.put(...
package com.qiuzq.jz.service.impl;import java.util.Collections;import java.util.HashMap;import java.util.Hashtable;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;/*...
新建package和Class(步骤略过,可自行选择名字),这里就使用jsonTest。 以下代码块方法见注释,是将JSONObject转换为HashMap的主要方法,传入参数为一个JSONObject对象,返还值为一个HashMap。 1 2 3 4 5 6 7 8 9 10 11 12 //1.將JSONObject對象轉換為HashMap<String,String> public static HashMap<String, ...
1.Introduction to JavaWeakHashMap TheWeakHashMapclass (present injava.util package) is aHashTable-based implementation ofMapInterface and is present sinceJava version 1.2.It has almost same features asHashMapincluding the constructors, methods, performance, andinternal implementation. ...