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Hutool是一个小而全的Java工具类库，通过静态方法封装，降低相关API的学习成本，提高工作效率，使Java拥有函数式语言般的优雅，让Java语言也可以“甜甜的”。

There is a newer version: 5.8.34

package cn.hutool.core.map;

import cn.hutool.core.util.JdkUtil;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;

/**
 * 安全的ConcurrentHashMap实现

 * 此类用于解决在JDK8中调用{@link ConcurrentHashMap#computeIfAbsent(Object, Function)}可能造成的死循环问题。

 * 方法来自Dubbo，见：issues#2349

 * 
 * 相关bug见：@see https://bugs.openjdk.java.net/browse/JDK-8161372
 *
 * @param  键类型
 * @param  值类型
 */
public class SafeConcurrentHashMap extends ConcurrentHashMap {
	private static final long serialVersionUID = 1L;

	// region == 构造 ==

	/**
	 * 构造，默认初始大小（16）
	 */
	public SafeConcurrentHashMap() {
		super();
	}

	/**
	 * 构造
	 *
	 * @param initialCapacity 预估初始大小
	 */
	public SafeConcurrentHashMap(int initialCapacity) {
		super(initialCapacity);
	}

	/**
	 * 构造
	 *
	 * @param m 初始键值对
	 */
	public SafeConcurrentHashMap(Map m) {
		super(m);
	}

	/**
	 * 构造
	 *
	 * @param initialCapacity 初始容量
	 * @param loadFactor      增长系数
	 */
	public SafeConcurrentHashMap(int initialCapacity, float loadFactor) {
		super(initialCapacity, loadFactor);
	}

	/**
	 * 构造
	 *
	 * @param initialCapacity  初始容量
	 * @param loadFactor       增长系数
	 * @param concurrencyLevel 并发级别，即Segment的个数
	 */
	public SafeConcurrentHashMap(int initialCapacity,
								 float loadFactor, int concurrencyLevel) {
		super(initialCapacity, loadFactor, concurrencyLevel);
	}
	// endregion == 构造 ==

	@Override
	public V computeIfAbsent(K key, Function mappingFunction) {
		if (JdkUtil.IS_JDK8) {
			return MapUtil.computeIfAbsentForJdk8(this, key, mappingFunction);
		} else {
			return super.computeIfAbsent(key, mappingFunction);
		}
	}
}