19.Java5同步集合类的应用

public class User implements Cloneable{
    private String name;
    private int age;
    
    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }
    public boolean equals(Object obj) {
        if(this == obj) {
            return true;
        }
        if(!(obj instanceof User)) {
            return false;    
        }
        User user = (User)obj;
        //if(this.name==user.name && this.age==user.age)
        if(this.name.equals(user.name) 
            && this.age==user.age) {
            return true;
        }
        else {
            return false;
        }
    }
    public int hashCode() {
        return name.hashCode() + age;
    }
    
    public String toString() {
        return "{name:‘" + name + "‘,age:" + age + "}";
    }
    public Object clone()  {
        Object object = null;
        try {
            object = super.clone();
        } catch (CloneNotSupportedException e) {}
        return object;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
} 

 1 import java.util.Collection;
 2 import java.util.Iterator;
 3 import java.util.concurrent.CopyOnWriteArrayList;
 4 
 5 /**
 6  * 迭代集合的时候不能增加、删除,如果修改了，next()方法中的版本号就会出现不一致了。
 7  * @author LiTaiQing
 8  *
 9  */
10 public class CollectionModifyExceptionTest {
11     public static void main(String[] args) {
12         Collection<User> users = new CopyOnWriteArrayList<User>();
13             
14             //new ArrayList();
15         users.add(new User("张三",28));    
16         users.add(new User("李四",25));            
17         users.add(new User("王五",31));    
18         Iterator<User> itrUsers = users.iterator();
19         while(itrUsers.hasNext()){
20             System.out.println("aaaa");
21             User user = (User)itrUsers.next();
22             if("李四".equals(user.getName())){
23                 users.remove(user);
24                 //itrUsers.remove();
25             } else {
26                 System.out.println(user);                
27             }
28         }
29     }
30 }