java之集合高级的运用

高级的运用"/>

java之集合高级的运用

学习java的第三十一天

• • 作业：
  • Employee 类
  • Book 类
  • Product 类
  • Nanny 类
  • HomeMain 测试类

作业：

1. 使用TreeSet添加员工对象，并按照ID倒序排列。
2. 使用LinkedHashSet添加10个书籍对象，并循环输出观察顺序
3. 掌握TreeSet、LinkedHashSet与HashSet的异同
4. 使用HashTable和ConcurrentHashMap添加10个产品对象，并重写hashCode和equals方法，比较记忆他们余HashMap的异同。
5. 使用LinkedHashMap添加10个保姆对象，并分别观察使用accessOrder和不使用accessOrder的区别，并掌握这些区别。

Employee 类

package com.qf.entity;public class Employee implements Comparable<Object> {private int id;//编号private String name;//名字private String sex;//性别private int age;//年龄private String dept;//部门public Employee() {super();// TODO Auto-generated constructor stub}public Employee(int id, String name, String sex, int age, String dept) {super();this.id = id;this.name = name;this.sex = sex;this.age = age;this.dept = dept;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getDept() {return dept;}public void setDept(String dept) {this.dept = dept;}@Overridepublic String toString() {return "Employee [id=" + id + ", name=" + name + ", sex=" + sex + ", age=" + age + ", dept=" + dept + "]";}@Overridepublic int compareTo(Object o) {if(o instanceof Employee){Employee e = (Employee) o;if(e.id > this.id){return 1;}else if (e.id < this.id) {return -1;}}return 0;}}

Book 类

package com.qf.entity;public class Book {private int id;//编号private String name;//名称private String type;//类型public Book() {super();// TODO Auto-generated constructor stub}public Book(int id, String name, String type) {super();this.id = id;this.name = name;this.type = type;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getType() {return type;}public void setType(String type) {this.type = type;}@Overridepublic String toString() {return "Book [id=" + id + ", name=" + name + ", type=" + type + "]";}}

Product 类

package com.qf.entity;public class Product {private int id;//编号private String name;//名称private String type;//类型 public Product() {super();// TODO Auto-generated constructor stub}public Product(int id, String name, String type) {super();this.id = id;this.name = name;this.type = type;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getType() {return type;}public void setType(String type) {this.type = type;}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result + id;result = prime * result + ((name == null) ? 0 : name.hashCode());result = prime * result + ((type == null) ? 0 : type.hashCode());return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;Product other = (Product) obj;if (id != other.id)return false;if (name == null) {if (other.name != null)return false;} else if (!name.equals(other.name))return false;if (type == null) {if (other.type != null)return false;} else if (!type.equals(other.type))return false;return true;}@Overridepublic String toString() {return "Product [id=" + id + ", name=" + name + ", type=" + type + "]";}}

Nanny 类

package com.qf.entity;public class Nanny {private int id;//编号private String name;//名字private String type;//类型public Nanny() {super();// TODO Auto-generated constructor stub}public Nanny(int id, String name, String type) {super();this.id = id;this.name = name;this.type = type;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getType() {return type;}public void setType(String type) {this.type = type;}@Overridepublic String toString() {return "Nanny [id=" + id + ", name=" + name + ", type=" + type + "]";}}

HomeMain 测试类

package com.qf.test;import java.util.Hashtable;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;import com.qf.entity.Book;
import com.qf.entity.Employee;
import com.qf.entity.Nanny;
import com.qf.entity.Product;public class HomeMain {public static void main(String[] args) {System.out.println("1. 使用TreeSet添加员工对象，并按照ID倒序排列");TreeSet<Employee> treeSet = new TreeSet<>();Employee e1 = new Employee(1, "张三", "男", 25, "人事部");Employee e2 = new Employee(2, "张三", "男", 26, "人事部");Employee e3 = new Employee(3, "张三", "男", 27, "人事部");Employee e4 = new Employee(4, "张三", "男", 28, "人事部");Employee e5 = new Employee(5, "张三", "男", 29, "人事部");//乱序添加treeSet.add(e4);treeSet.add(e5);treeSet.add(e1);treeSet.add(e3);treeSet.add(e2);//根据id在控制台降序打印,需在实体类写compareTo方法,继承Comparable类Iterator<Employee> iterator = treeSet.iterator();while(iterator.hasNext()){System.out.println(iterator.next());}System.out.println("2. 使用LinkedHashSet添加10个书籍对象，并循环输出观察顺序");//LinkedHashSet便利时根据添加顺序进行打印LinkedHashSet<Book> linkedHashSet = new LinkedHashSet<>();Book b1 = new Book(1, "财运天降", "小说");Book b2 = new Book(2, "西游记", "小说");Book b3 = new Book(3, "红楼梦", "小说");Book b4 = new Book(4, "三国演义", "小说");Book b5 = new Book(5, "水浒传", "小说");Book b6 = new Book(6, "数学", "教材");Book b7 = new Book(7, "语文", "教材");Book b8 = new Book(8, "英语", "教材");Book b9 = new Book(9, "物理", "教材");Book b10 = new Book(10, "生物", "教材");linkedHashSet.add(b1);linkedHashSet.add(b2);linkedHashSet.add(b4);linkedHashSet.add(b3);linkedHashSet.add(b5);linkedHashSet.add(b7);linkedHashSet.add(b6);linkedHashSet.add(b8);linkedHashSet.add(b9);linkedHashSet.add(b10);Iterator<Book> iterator2 = linkedHashSet.iterator();while(iterator2.hasNext()){System.out.println(iterator2.next());}System.out.println("3. 掌握TreeSet、LinkedHashSet与HashSet的异同");System.out.println("//相同点:元素不能重复,方法大致一样.");System.out.println("//不同点:HashSet是无序的,可以添加null元素;LinkedHashSet是有序的,可以添加null元素，顺序是根据你添加的顺序;");System.out.println("TreeSet是有序的,不能添加null元素;,默认顺序是根据你添加的顺序,也可以按照指定方式,在添加元素时就进行排序,需在实体类写compareTo方法,继承Comparable类.");System.out.println("4. 使用HashTable和ConcurrentHashMap添加10个产品对象，并重写hashCode和equals方法，比较记忆他们余HashMap的异同。");//HashTable是倒序的,是线程安全的,ConcurrentHashMap是正序的,线程不安全Hashtable<String, Product> hashtable = new Hashtable<>();ConcurrentHashMap<String,Product> concurrentHashMap = new ConcurrentHashMap<>();Product p1 = new Product(1, "苹果", "手机");Product p2 = new Product(2, "华为", "手机");Product p3 = new Product(3, "三星", "手机");Product p4 = new Product(4, "魅族", "手机");Product p5 = new Product(5, "小米", "手机");Product p6 = new Product(6, "苹果", "电脑");Product p7 = new Product(7, "惠普", "电脑");Product p8= new Product(8, "联想", "电脑");Product p9 = new Product(9, "华硕", "电脑");Product p10 = new Product(10, "戴尔", "电脑");hashtable.put("a", p1);hashtable.put("b", p2);hashtable.put("c", p3);hashtable.put("d", p4);hashtable.put("e", p5);hashtable.put("f", p6);hashtable.put("g", p7);hashtable.put("h", p8);hashtable.put("i", p9);hashtable.put("j", p10);Iterator<String> iterator3 = hashtable.keySet().iterator();while(iterator3.hasNext()){String key1 = iterator3.next();System.out.println(key1+"==="+hashtable.get(key1));}concurrentHashMap.put("a", p1);concurrentHashMap.put("b", p2);concurrentHashMap.put("c", p3);concurrentHashMap.put("d", p4);concurrentHashMap.put("e", p5);concurrentHashMap.put("f", p6);concurrentHashMap.put("g", p7);concurrentHashMap.put("h", p8);concurrentHashMap.put("i", p9);concurrentHashMap.put("j", p10);Iterator<String> iterator4 = concurrentHashMap.keySet().iterator();while(iterator4.hasNext()){String key2 = iterator4.next();System.out.println(key2+"==="+concurrentHashMap.get(key2));}System.out.println("5. 使用LinkedHashMap添加10个保姆对象，并分别观察使用accessOrder和不使用accessOrder的区别，并掌握这些区别。");//LinkedHashMap是顺序的,不使用accessOrder时:对元素进行访问,位置不变;使用accessOrder时:对元素进行访问,该元素位置放到链表末尾.LinkedHashMap<String,Nanny> linkedHashMap1 = new LinkedHashMap<>();LinkedHashMap<String,Nanny> linkedHashMap2 = new LinkedHashMap<>(4,0.75f,true);Nanny n1 = new Nanny(1, "张阿姨", "做饭");Nanny n2 = new Nanny(2, "李阿姨", "洗衣服");Nanny n3 = new Nanny(3, "王阿姨", "拖地");Nanny n4 = new Nanny(4, "赵阿姨", "带小孩");Nanny n5 = new Nanny(5, "周阿姨", "暖被窝");Nanny n6 = new Nanny(6, "郑阿姨", "陪逛街");Nanny n7 = new Nanny(7, "刘阿姨", "赚钱");Nanny n8 = new Nanny(8, "孙阿姨", "挡酒");Nanny n9 = new Nanny(9, "徐阿姨", "司机");Nanny n10 = new Nanny(10, "郭阿姨", "保镖");linkedHashMap1.put("a", n1);linkedHashMap1.put("b", n2);linkedHashMap1.put("c", n3);linkedHashMap1.put("d", n4);linkedHashMap1.put("e", n5);linkedHashMap1.put("f", n6);linkedHashMap1.put("g", n7);linkedHashMap1.put("h", n8);linkedHashMap1.put("i", n9);linkedHashMap1.put("j", n10);linkedHashMap1.get("a");Iterator<String> iterator5 = linkedHashMap1.keySet().iterator();while(iterator5.hasNext()){String key3 = iterator5.next();System.out.println(key3+"==="+linkedHashMap1.get(key3));}linkedHashMap2.put("a", n1);linkedHashMap2.put("b", n2);linkedHashMap2.put("c", n3);linkedHashMap2.put("d", n4);linkedHashMap2.put("e", n5);linkedHashMap2.put("f", n6);linkedHashMap2.put("g", n7);linkedHashMap2.put("h", n8);linkedHashMap2.put("i", n9);linkedHashMap2.put("j", n10);linkedHashMap2.get("a");Iterator<String> iterator6 = linkedHashMap2.keySet().iterator();while(iterator6.hasNext()){String key4 = iterator6.next();System.out.println(key4);}Iterator<Nanny> iterator7 = linkedHashMap2.values().iterator();while(iterator7.hasNext()){System.out.println(iterator7.next());}}}