Iterator类位于java.util包中，使用前要先引入，以下是其语法格式：import java.util.Iterator; // 引入 Iterator 类 2、获取一个迭代器 可以使用Iterator()方法在集合中获取一个迭代器，示例如下：// 引入 ArrayList 和 Iterator 类 import java.util.ArrayList;import java.util.Iterator;public class MiukuTest {...
ConcurrentModificationException官方文档第一句就指出: This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible. 这时候可以采用java.util.concurrent包下面的线程安全的容器解决此异常。 最后要说的是,ConcurrentModificationException应该...
publicEnext(){checkForComodification();int i=cursor;//记录索引位置if(i>=size)//如果获取元素大于集合元素个数,则抛出异常thrownewNoSuchElementException();Object[]elementData=ArrayList.this.elementData;if(i>=elementData.length)thrownewConcurrentModificationException();cursor=i+1;//cursor + 1return(E)...
Skip navigation links Java SE 17 & JDK 17 Overview Module Package Class Use Tree Preview New Deprecated Index Help Summary: Nested | Field | Constr | Method Detail: Field | Constr | Method SEARCH: Module java.base Package java.util Interface Iterator<E> Type Parameters: E - the type of ...
/*** Tests whether the iterator has a next object.* @return true if there are further objects, false otherwise*/publicbooleanhasNext(){returnj<size;}// size is field of outer instance/*** Returns the next object in the iterator.** @return next object* @throws NoSuchElementException if ...
Object[] elementData = ArrayList.this.elementData;if (i >=elementData.length)thrownewConcurrentModificationException(); cursor = i + 1;return (E) elementData[lastRet =i]; } 在next()方法中有一个checkForComodification()方法,其实现为: finalvoidcheckForComodification() ...
Object obj=it.next();if("three".equals(obj)){ it.add("four");//[one, two, three, four, five]//it.set("3");//[one, two, 3, five]//对比输出结果} } System.out.println(list); } } 2、增强for循环: (1)for(元素的数据类型 变量:Collection集合or数组){ }; ...
An Iterator is an object that can be used to loop through collections, like ArrayList and HashSet. It is called an "iterator" because "iterating" is the technical term for looping.To use an Iterator, you must import it from the java.util package....
In this tutorial, we will learn about the Java Iterator interface with the help of an example. All the Java collections include an iterator() method. This method returns an instance of iterator used to iterate over elements of collections.
boolean remove(Object o); 1. 从该集合中删除指定元素的单个实例(如果存在)(可选操作)。 如果该集合中有多个相同元素,则删除第一个。删除元素后,后面的元素会往前移。返回值为布尔型。 boolean equals(Object o); 1. 将指定的对象与此集合进行比较以获得相等性。 返回值为布尔型。