Java集合 Map 嵌套 Map

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/*
 *  Map集合的嵌套,Map中存儲的還是Map集合
 *  要求:
 *    傳智播客  
 *      Java基礎班
 *        001  張三
 *        002  李四
 *      
 *      Java就業班
 *        001  王五
 *        002  趙六
 *  對以上數據進行對象的存儲   
 *   基礎班Map   <學號,姓名>
 *   就業班Map   <學號,姓名>
 *   傳智播客Map  <班級名字, 基礎班Map>
 */
public class TestMapMap {

    public static void main(String[] args) {
        
        HashMap<String, String> javaSEmap = new HashMap<String, String>();
        javaSEmap.put("001", "張三");
        javaSEmap.put("002", "李四");
        
        HashMap<String, String> javaEEmap = new HashMap<String, String>();
        javaEEmap.put("001", "王五");
        javaEEmap.put("002", "趙六");
        
        HashMap<String, HashMap<String, String>> czmap = new HashMap<String, HashMap<String, String>>();
        czmap.put("基礎班", javaSEmap);
        czmap.put("就業班", javaEEmap);
        
        Set<Map.Entry<String, HashMap<String, String>>> classNameSet = czmap.entrySet();
        Iterator<Map.Entry<String, HashMap<String, String>>> classNameit = classNameSet.iterator();
        
        while(classNameit.hasNext()){
            Map.Entry<String, HashMap<String, String>> classEntry = classNameit.next();
            String classNameKey = classEntry.getKey();
            HashMap<String, String> classMap = classEntry.getValue();
            
            Set<Map.Entry<String, String>> studentSet = classMap.entrySet();
            Iterator<Map.Entry<String, String>> studentIt = studentSet.iterator();
            while(studentIt.hasNext()){
                Map.Entry<String, String> studentEntry = studentIt.next();
                String skey = studentEntry.getKey();
                String svalue = studentEntry.getValue();
                
                System.out.println( classNameKey + "_" +skey+ "_"+svalue);
                
            }
            
        }
        
        

    }

}