Java集合的互相巢狀以及TreeMap集合獲取字串中不同字元數量例項
阿新 • • 發佈：2018-11-11
文章目錄
1、獲取輸入字串中每個字元的個數
package test12_TreeMap;
import java.util.Scanner;
import java.util. 輸出結果：
2、ArrayList巢狀HashMap
package test13_Nest;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;
/*
* ArrayList巢狀HashMap
*
* 一共有兩組HashMap
* 小明-踢球
* 小王-游泳
*
* 小紅-唱歌
* 小麗-畫畫
*/
public class ArrayListNestHashMap {
public static void main(String[] args) {
ArrayList<HashMap<String,String>> al=new ArrayList<HashMap<String,String>>();
HashMap<String,String> hm1=new HashMap<String,String>();
HashMap<String,String> hm2=new HashMap<String,String>();
hm1.put("小明", "踢球");
hm1.put("小王", "游泳");
hm2.put("小紅", "小紅");
hm2.put("小麗", "畫畫");
al.add(hm1);
al.add(hm2);
for(HashMap<String,String> hm:al) {
Set <String> set=hm.keySet();
for(String key:set) {
String value=hm.get(key);
System.out.println(key+"--"+value);
}
}
}
}
輸出結果
3、HashMap巢狀ArrayList
package test13_Nest;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;
/*
* 實現HashMap巢狀ArrayList
* man
* 小明
* 小王
* woman
* 小紅
* 小麗
*/
public class HashMapNestArrayList {
public static void main(String[] args) {
HashMap<String,ArrayList<String>> hm=new HashMap<String,ArrayList<String>>();
ArrayList<String> al1=new ArrayList<String>();
al1.add("小明");
al1.add("小王");
ArrayList<String> al2=new ArrayList<String>();
al2.add("小紅");
al2.add("小麗");
hm.put("man", al1);
hm.put("woman", al2);
Set<String> set=hm.keySet();
for(String key:set) {
ArrayList<String> value=hm.get(key);
System.out.println(key);
for(String s:value) {
System.out.println("\t"+s);
}
}
}
}
輸出結果
4、HashMap巢狀HashMap
package test13_Nest;
import java.util.HashMap;
import java.util.Set;
/*
* 實現HashMap巢狀HashMap
* 鍵 值 鍵 值
* Man 男人Map :
* 1、 小明 20
* 2、 小王 22
* Woman 女人Map：
* 1、 小紅 18
* 2、 小麗 16
*/
public class HashMapNestHashMap {
public static void main(String[] args) {
//建立HashMap物件
HashMap<String,HashMap<String,Integer>> peopleMap=new HashMap<String,HashMap<String,Integer>>();
HashMap<String,Integer> manMap=new HashMap<String,Integer>();
HashMap<String,Integer> womanMap=new HashMap<String,Integer>();
//新增元素
manMap.put("小明", 20);
manMap.put("小王", 22);
peopleMap.put("man", manMap);
womanMap.put("小紅", 18);
womanMap.put("小麗", 16);
peopleMap.put("woman", womanMap);
//遍歷
Set <String> peopleMapSet=peopleMap.keySet();
for(String peopleMapKey:peopleMapSet) {
HashMap<String,Integer> peopleMapValue=peopleMap.get(peopleMapKey);
System.out.println(peopleMapKey);
Set<String> peopleMapValueSet=peopleMapValue.keySet();
for(String peopleMapValueKey:peopleMapValueSet) {
Integer peopleMapValueValue=peopleMapValue.get(peopleMapValueKey);
System.out.println("\t"+peopleMapValueKey+":"+peopleMapValueValue);
}
}
}
}
輸出結果
5、HashMap巢狀HashMap再巢狀ArrayList
三層巢狀，ArrayList儲存的是學生物件
巢狀程式
package test13_Nest;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;
/*
* 實現三層巢狀：HashMap巢狀HashMap再巢狀ArrayList
* 這次的ArrayList儲存的是學生物件
*
* 通訊學院：
* 2班
* 小紅18歲
* 小李18歲
* 12班
* 小王19歲
* 小麗18歲
* 電子學院：
* 1班
* 小芳18歲
* 小明20歲
* 11班
* 小趙20歲
* 小軍19歲
*/
public class ThreeNest {
public static void main(String[] args) {
HashMap<String,HashMap<String,ArrayList<Student>>> hm=
new HashMap<String,HashMap<String,ArrayList<Student>>>();
HashMap<String,ArrayList<Student>> hm1=new HashMap<String,ArrayList<Student>>();
HashMap<String,ArrayList<Student>> hm2=new HashMap<String,ArrayList<Student>>();
ArrayList<Student> a1=new ArrayList<Student>();
ArrayList<Student> a2=new ArrayList<Student>();
ArrayList<Student> a3=new ArrayList<Student>();
ArrayList<Student> a4=new ArrayList<Student>();
Student s1=new Student("小紅",18);
Student s2=new Student("小李",18);
Student s3=new Student("小王",19);
Student s4=new Student("小麗",18);
Student s5=new Student("小芳",18);
Student s6=new Student("小明",20);
Student s7=new Student("小趙",20);
Student s8=new Student("小軍",19);
a1.add(s1);
a1.add(s2);
a2.add(s3);
a2.add(s4);
a3.add(s5);
a3.add(s6);
a4.add(s7);
a4.add(s8);
hm1.put("2班", a1);
hm1.put("12班", a2);
hm2.put("1班", a3);
hm2.put("11班", a4);
hm.put("通訊學院", hm1);
hm.put("電子學院", hm2);
Set <String> hmSet=hm.keySet();
for(String hmKey: hmSet) {
HashMap<String,ArrayList<Student>> hmValue=hm.get(hmKey);
System.out.println(hmKey);
Set<String> hmValueSet=hmValue.keySet();
for(String hmValueKey:hmValueSet) {
ArrayList<Student> hmValueValue=hmValue.get(hmValueKey);
System.out.println("\t"+hmValueKey);
for(Student al:hmValueValue) {
System.out.println("\t\t"+al.getName()+al.getAge()+"歲");
}
}
}
}
}
學生類程式
package test13_Nest;
public class Student {
private String name;
private int age;
public Student() {
super();
// TODO Auto-generated constructor stub
}
public Student(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
輸出結果
