Java统计List中每个元素出现的次数

    int countA = Collections.frequency(list, "a");

Collections.frequency(list, key)

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Test {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("a");
        list.add("b");
        list.add("b");
        int countA = Collections.frequency(list, "a");
        int countB = Collections.frequency(list, "b");
        System.out.println(countA);
        System.out.println(countB);
    }
}

从源码里面进去看Collections.frequency(list, “a”)
实际上可以根据自己需要去改造一下

private int getCount(List<JiHaiBrandResp> jiHaiPoiRespList, String brandName) {
        int count = 0;
        if (null != brandName) {
            for (JiHaiBrandResp haiBrandResp : jiHaiPoiRespList) {
                if (brandName.equals(haiBrandResp.getBrandName())) {
                    count++;
                }
            }
        }
        return count;
    }