集合嵌套 - 黑马程序员技术交流社区

import java.util.*;
import java.util.Map.Entry;
public class Demo
{
public static void main(String[] args)
{
HashMap<String, HashMap<String, String>> 传智博客=new HashMap<String, HashMap<String, String>>();
HashMap<String,String> 基础班=new HashMap<String,String>();
HashMap<String,String> 就业班=new HashMap<String,String>();
基础班.put("001", "zhangsan1");
基础班.put("002", "zhangsan2");
基础班.put("003", "zhangsan3");
就业班.put("001", "lisi1");
就业班.put("002", "lisi2");
就业班.put("003", "lisi3");
传智博客.put("基础教学", 基础班);
传智博客.put("企业教学", 就业班);
keySet(传智博客);
}
//entrySet方式获取
public static void entrySet(HashMap<String,HashMap<String,String>> 传智博客){
Set<Map.Entry<String,HashMap<String,String>>> set=传智博客.entrySet();
Iterator <Map.Entry<String,HashMap<String,String>>> it=set.iterator();
while(it.hasNext()){
Map.Entry<String,HashMap<String,String>> cz=it.next();
String key=cz.getKey();
HashMap<String,String> value =cz.getValue();
System.out.println(key+":");
Set<Entry<String, String>> set2=value.entrySet();
Iterator <Map.Entry<String,String>> it2=set2.iterator();
while(it2.hasNext()){
Map.Entry<String, String> cz2=it2.next();
String key2=cz2.getKey();
String value2=cz2.getValue();
System.out.println(key2+"..."+value2);
}
}
}
//KeySet方式获取
public static void keySet(HashMap<String, HashMap<String, String>> 传智博客){
Set<String> set=传智博客.keySet();
Iterator<String> it=set.iterator();
while(it.hasNext()){
String key=it.next();
HashMap<String,String> map=传智博客.get(key);
System.out.println(key+":");
Set<String> set2=map.keySet();
Iterator <String> it2=set2.iterator();
while(it2.hasNext())
{
String key2=it2.next();
String map2=map.get(key2);
System.out.println(key2+"+++"+map2);
}
}
}
}
//学生类
class Student
{
private String name;
private String xuehao;
public void stady(){
System.out.println("学习");
}
public Student(){}
public Student(String name,String xuehao){
this.name=name;
this.xuehao=xuehao;
}
public boolean equals(Object obj){
if(this==obj)
return true;
if(obj==null)
return false;
if(obj instanceof Student)
{
Student stu=(Student)obj;
return this.name.equals(stu.name);
}
return false;
}
public int hashCode(){
return this.name.hashCode()+this.xuehao.hashCode();
}
public String toString(){
return "Student: "+name+"..."+xuehao;
}
//----------------gs-----------------------
public void setName(String name){
this.name=name;
}
public String getName(){
return name;
}
public void setXuehao(String xuehao){
this.xuehao =xuehao;
}
public String getXuehao(){
return xuehao;
}
}
//基础班学生类
class JCStudent extends Student
{
public void stady(){
System.out.println("基础学习");
}
}
//就业班学生类
class JYStudent extends Student
{
public void stady(){
System.out.println("就业学习");
}
}

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