编辑代码

import java.util.Map;
import java.util.HashMap;

public class Demo14{

    public static void main(String[] args) {
        Map<String,String>map = new HashMap<>();
        map.put("name","一哥")；
        map.put("age","30");
        map.put("sex","男");
        System.out.println("map="+map);
    }
}

public class Demo15{

    public static void main(String[] args) {
        Map<String,String>map = new HasMap<>();
        map.put("name","一哥")；
        map.put("age","30");
        map.put("sex","男");
        String sex = map.getOrDefault("sex","男");
        String height = map.getOrDefault("height","0");
        System.out.println("[name]="+name+" ,[age]="+age+",[sex]="
        +sex+",[height]=")
    }
}

public class Demo16{

    public static void main(String[] args){
        Map<String,String>map = new HashMap<>();
        map.put("name","一哥")；
        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 class Demo17{
    public static void main(String[] args) {
        Map<String,String>map1 = new HashMap<>();
        map.put("name","一哥")；
        map.put("age","30");
        map.put("sex","男");
    }
}