JavaCollection框架Demo

Collection框架Demo（java.util.Collection）

1，Collection集合的基本Demo:

package com.hpioneer.collection;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Objects;

/**
 * @Description: ColLection轉數組遍歷
 * @Author: HPioneer
 * @CreateTime: 2018/5/7  17:40
 * @File: Collection of JavaProject in com.hpioneer.collection
 * @FullFileName: com.hpioneer.collection.Collection
 * @Create By IntelliJ
 * @Version: 1.0
 */
public class Demo_Collection { public static void main(String[] args) { Collection c = new ArrayList(); boolean b1 = c.add("abc"); boolean b2 = c.add(true); //自動裝箱new Boolean(true); boolean b3 = c.add(100); boolean b4 = c.add(new Student("張三",23)); boolean b5 = c.add("abc"); System.out.println(b1); System.out.println(b2); System.out.println(b3); System.out.println(b4); System.out.println(b5); System.out.println(c.toString()); Object[] arr = c.toArray(); for (int i =0 ;i<arr.length;i++){ System.out.println(arr[i]); } System.out.println(c.size()); System.out.println(c); } }

2，Collection迭代器遍歷

package com.hpioneer.collection;

import sun.plugin.WJcovUtil;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

/**
 * @Description:
 * @Author: HPioneer
 * @CreateTime: 2018/5/7  17:51
 * @File: Iterator of JavaProject in com.hpioneer.collection
 * @FullFileName: com.hpioneer.collection.Iterator
 * @Create By IntelliJ
 * @Version: 1.0
 */
public class Demo_Iterator { public static void main(String[] args) { Collection c = new ArrayList(); c.add(new Student("張三",23)); c.add(new Student("李四",25)); c.add(new Student("王五",25)); Iterator it = c.iterator(); while (it.hasNext()){ Student s = (Student) it.next(); System.out.println(s.getName()+" "+s.getAge()); } } }

3，ListIterator

package com.hpioneer.collection;

import java.util.List;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Objects;
import java.util.ListIterator;

/**
 * @Description: ListIterator的add,遍歷元素，集合修改元素
 * @Author: HPioneer
 * @CreateTime: 2018/5/7  17:40
 * @File: Collection of JavaProject in com.hpioneer.collection
 * @FullFileName: com.hpioneer.collection.Collection
 * @Create By IntelliJ
 * @Version: 1.0
 */
public class Demo_Collection { public static void main(String[] args) { List list = new ArrayList(); list.add("a"); //Object obj = new String(); list.add("b"); list.add("world"); list.add("c"); list.add("d"); list.add("e"); ListIterator lit = list.listIterator(); //獲取迭代器(List集合特有的) while(lit.hasNext()) { String str = (String)lit.next(); //向下轉型 if("world".equals(str)) { //list.add("javaee"); //遍歷的同時在增長元素,併發修改ConcurrentModificationException lit.add("javaee"); } } System.out.println(list); } }

4，Vector的迭代

package com.hpioneer.collection;

import java.util.Enumeration;
import java.util.Vector;

/**
 * @Description:
 * @Author: HPioneer
 * @CreateTime: 2018/5/7  18:14
 * @File: Demo_Vector of JavaProject in com.hpioneer.collection
 * @FullFileName: com.hpioneer.collection.Demo_Vector
 * @Create By IntelliJ
 * @Version: 1.0
 */
public class Demo_Vector { public static void main(String[] args) { Vector v = new Vector(); v.addElement("a"); v.addElement("b"); v.addElement("c"); v.addElement("d"); Enumeration en = v.elements(); //獲取枚舉 while(en.hasMoreElements()) { //判斷集合中是否有元素 System.out.println(en.nextElement()); //獲取集合中的元素  } } }