com.github.shaohj.sstool.core.util.MapUtil Maven / Gradle / Ivy
package com.github.shaohj.sstool.core.util;
import java.util.Map;
/**
* 编 号:
* 名 称:MapUtil
* 描 述:
* 完成日期:2019/6/29 10:28
* @author:felix.shao
*/
public class MapUtil {
/** hashmap默认加载因子 */
public static final float DEFAULT_LOAD_FACTOR = 0.75f;
public static void main(String[] args) {
System.out.println(calMapSize(7));
}
/**
* 计算Map的默认容量
* @param size eq:10, return 10 * DEFAULT_LOAD_FACTOR
* @return
*/
public static int calMapCapacity(int size){
return ((int)(size * DEFAULT_LOAD_FACTOR));
}
public static int calMapSize(int capacity){
return ((int)(capacity / DEFAULT_LOAD_FACTOR) + 1);
}
/**
* map是否为空
* @param map
* @return
*/
public static boolean isEmpty(Map map) {
return null == map || map.isEmpty();
}
}