在java中将两个数组列表合并成一个TreeMap

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.TreeMap;

ArrayList<Integer> list1 = new ArrayList<>();
list1.add(1);
list1.add(3);
list1.add(5);

ArrayList<Integer> list2 = new ArrayList<>();
list2.add(2);
list2.add(4);
list2.add(6);

ArrayList<Integer> mergedList = new ArrayList<>();
mergedList.addAll(list1);
mergedList.addAll(list2);
Collections.sort(mergedList);

TreeMap<Integer, Integer> treeMap = new TreeMap<>();
for (int i = 0; i < mergedList.size(); i++) {
    treeMap.put(i, mergedList.get(i));
}

for (Integer key : treeMap.keySet()) {
    System.out.println("Key: " + key + ", Value: " + treeMap.get(key));
}