编辑代码

import java.util.Map;
import java.util.Map.Entry;
import java.util.HashMap;
import java.util.Set;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.LinkedList;
class Demo16{
    public static void main(String[] args){
        Map<String,String> map = new HashMap<>();
        map.put("name","--哥");
        map.put("age","30");
        map.put("sex","男");
        Set<Entry<String,String>> entrySet = map.entrySet();
        Iterator<Map.Entry<String,String>> iterator = entrySet.iterator();
        while (iterator.hasNext()){
            Map.Entry<String,String> entry = iterator.next();
            String key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key + "=" + value);
        }
        for(Map.Entry<String,String> entry : map.entrySet()){
            String key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key + "=" + value);
        }
    }
    public static void addArrayList(){
        long start = System.currentTimeMillis();
        ArrayList<Integer> arrayList = new ArrayList<>();
        for (int i = 1; i <= 10000000 ; i++) {
            arrayList.add(i);
        }
        long end = System.currentTimeMillis();
        System.out.println("耗时:" + (end - start));
    }
    public static void addLinkedList(){
        long start = System.currentTimeMillis();
        LinkedList<Integer> linkedList = new LinkedList<>();
        for (int i = 1; i <= 10000000 ; i++) {
            linkedList.add(i);
        }
        long end = System.currentTimeMillis();
        System.out.println("耗时:" + (end - start));
    }
}