public class Person implements Comparable<Person>{

     String name;

     String id;

     public Person(String name,String id) {

         this.name=name;

         this.id=id;

     }

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public String getId() {

         return id;

     }

     public void setId(String id) {

         this.id = id;

     }

     public boolean equals(Object o) {

         if(!(o instanceof Person)) {

             return false;

         }

         Person person=(Person) o;

         return this.id.equals(person.id);

     }

     @Override

     public int compareTo(Person o) {

         if(o==null)

             return ;

         return this.id.compareTo(o.id);

     }    

     public String toString() {

         return String.format("%s-%s", name,id);

     }

     public int hasCode() {

         return id.hashCode();

     }

 }

 import java.util.HashMap;

 import java.util.Map;

 import java.util.Map.Entry;

 import java.util.Set;

 import difficult.Person;

 public class HashMapDemo {

     public static void main(String[] args) {

         Map<String, Person> map=new HashMap<>();

         Person p1=new Person("张三", "");

         map.put(p1.getId(), p1);

         map.put("", new Person("", "李四"));

         map.put("", new Person("", "王五"));

         System.out.println(map);

         System.out.printf("%s-%s\n","",map.get(""));

         //增强型for，元素类型为Entry<String,Person>

         for(Entry<String, Person> entry:map.entrySet()) {

             System.out.printf("%s-%s ",entry.getKey(),entry.getValue());

         }

         System.out.println();

         //利用set来遍历

         Set<String> keys=map.keySet();

         for(String key:keys) {

             Person value=map.get(key);

             System.out.printf("%s-%s ",key,value);

         }

         System.out.println();

     }

 }

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 import difficult.Person;

 public class IterateList {

     public static void main(String[] args) {

         List<Person> persons = new ArrayList<>();//，List为一个接口，定义一个泛型为Person的ArrayList表

         Person p = new Person("1001", "张三");

         persons.add(p);

         persons.add(p);

         persons.add(new Person("1002", "李四"));

         persons.add(new Person("1003", "王五"));

         persons.add(new Person("1004", "沈六"));

         //遍历1：下标

         int len=persons.size();

         for(int i=0;i<len;i++) {

             Person person=persons.get(i);

             System.out.print(person+"\t");

         }

         System.out.println();

         //遍历2：迭代器

         Iterator<Person> iterator=persons.iterator();

         while(iterator.hasNext()) {

             Person person=iterator.next();

             System.out.print(person+"\t");

         }

         System.out.println();

         //遍历3：增强型for

         for(Person person:persons) {

             System.out.print(person+"\t");

         }

         System.out.println();

         int[] data= {1,3,5,7,9};

         for(int dat:data) {

             System.out.print(dat+"\t");

         }

     }

 }

 import java.util.ArrayList;

 import java.util.Enumeration;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Vector;

 import difficult.Person;

 public class VectorAndList {

     public static void main(String[] args) {

         List<Person> persons = new ArrayList<>();

         Person p = new Person("1001", "张三");

         persons.add(p);

         persons.add(p);

         persons.add(new Person("1002", "李四"));

         persons.add(new Person("1003", "王五"));

         persons.add(new Person("1004", "沈六"));

         // 遍历二：迭代器

         Iterator<Person> iterator=persons.iterator();

         while(iterator.hasNext()) {

             Person person=iterator.next();

             System.out.print(person+"\t");

         }

         System.out.println();

         //向量

         Vector<Person> vector=new Vector<>();

         vector.addAll(persons);

         //通过枚举遍历

         Enumeration<Person> enu=vector.elements();

         while(enu.hasMoreElements()) {

             Person person=enu.nextElement();

             System.out.print(person+"\t");

         }

         System.out.println();

     }

 }