hashmap怎么嵌套hashmap

hashmap怎么嵌套hashmap

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

public class Test {
public static void main(String[] args) {
Map map1 = new HashMap();
map1.put("hey1","val1");
map1.put("hey2","val2");
map1.put("hey3","val3");
map1.put("hey4","val4");

Map> map0 = new HashMap>();
map0.put("0",map1);
map0.put("1",map1);

System.out.println(map0.get("0").get("hey2"));
}
}
比较简单的一个例子

package dao;
import java.util.HashMap;
import java.util.Set;
public class HashMapExc
{
public static void main(String[] args)
{
HashMap map1=new HashMap();
HashMap map2=new HashMap();
map2.put("1", "a");
map2.put("2", "b");
map2.put("3", "c");
map1.put("0", map1);
Set keys=map2.keySet();
Object keyArray[]=keys.toArray();
HashMap map=(HashMap)map1.get("0");
for(int i=0;i<keyArray.length;i++)
{
System.out.println(map2.get(""+(i+1)));

}
}
}