import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; public class ConcurrentHashMapExample { public static void main(String[] args) { //ConcurrentHashMap Map<String,String> myMap = new ConcurrentHashMap<String,String>(); myM...
ConcurrentHashMap是一个与HashMap很相似的类,但是它支持在运行时修改集合对象。 让我们通过一个简单的程序来帮助理解: ConcurrentHashMapExample.java package com.journaldev.util; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; public...
下面是一个简单的ConcurrentHashMap使用示例: import java.util.concurrent.ConcurrentHashMap; public class ConcurrentHashMapExample { public static void main(String[] args) { // 创建一个 ConcurrentHashMap 实例 ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>(); // 插入数据 map.put(...
import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; public class ConcurrentHashMapExample { public static void main(String[] args) { //ConcurrentHashMap Map<String,String> myMap = new ConcurrentHashMap<String,String>(); myM...
computeIfAbsent(userId, id -> loadUserFromDatabase(id)); } private User loadUserFromDatabase(int userId) { // 模拟数据库查询 return new User(userId, "User Name", "email@example.com"); } } 解释: computeIfAbsent 方法确保了当缓存中没有某个用户时,只有一个线程能够从数据库加载用户...
import java.util.concurrent.ConcurrentHashMap; public class ConcurrentHashMapExample { public static void main(String[] args) { //ConcurrentHashMap Map<String,String> myMap = new ConcurrentHashMap<String,String>(); myMap.put("1", "1"); myMap.put("2", "1"); myMap.put("3", "1")...
import java.util.concurrent.ConcurrentHashMap; public class ConcurrentHashMapExample { // 定义一个线程安全的 ConcurrentHashMap private ConcurrentHashMap<String, Integer> sharedMap = new ConcurrentHashMap<>(); // 向 map 中添加元素的方法 public void putElement(String key, Integer value) { // 使用...
at com.test.ConcurrentHashMapExample.main(ConcurrentHashMapExample.java:44) 明显ConcurrentHashMap 可以支持向 map 中添加新元素,而 HashMap 则抛出了 ConcurrentModificationException。 介绍ConcurrentHashMap: ConcurrentHashMap (简称 CHM )是在 Java 1.5作为 Hashtable 的替代选择新引入的,是 concurrent 包的重要...
//import statement import java.util.*; import java.util.concurrent.ConcurrentHashMap; public class ConcurrentHashMaphashcodeExample1 { public static void main(String args[]) { ConcurrentHashMap<String , String> mymap = new ConcurrentHashMap<String ,String>(); ConcurrentHashMap<String , String> ...
packagecn.juwatech.concurrentdemo;importjava.util.concurrent.ConcurrentHashMap;publicclassConcurrentHashMapExample{publicstaticvoidmain(String[] args){// 创建一个ConcurrentHashMap实例ConcurrentHashMap<Integer, String> map =newConcurrentHashMap<>();// 添加元素map.put(1,"Apple"); ...