Collection 使用举例1

 

Collection 使用举例

 

容器类对象在调用remove，Collection 等方法时需要比较对象是否相等，这回涉及到对象类型的equals方法和hashCode方法，对于自定义的的类型
//需要重写equals和hashCode方法以实现自定义的对象相等规则。

package com.study;

import java.util.*;

public class CollectionDemo02 {
	
	public static void main(String []args) {
		
		Collection c1= new LinkedList();
		c1.add("CollectionDemo02");
		c1.add("CollectionDemo02");
		c1.add("CollectionDemo02");
		c1.add("CollectionDemo02");
		c1.add("TestCollection");
		
		c1.add(new Integer(100));
		c1.add(new Double(100.22));
		c1.add(new Boolean(true));
		c1.add(new Boolean(false));
		
		c1.add(new Desk("Office Desk 1","100","200"));
		c1.add(new Desk("Office Desk 2","200","400"));
		c1.add(new Desk("Office Desk 3","300","600"));
		
		Collection c2 = new ArrayList();
		c2.add(c1);
		c2.add("zhudansheng test Collection");
		System.out.println("==============================");
		System.out.println(c1);	//c1全部打印出来
		System.out.println("==============================");
		System.out.println(c2);	//把c1和c2数据全部打印出来
		System.out.println("==============================");
		c2.remove("TestCollection");	//为什么删除不掉呢？
		c2.remove("CollectionDemo02");	//为什么删除不掉呢？
		c2.remove(new Boolean(false));	//为什么删除不掉呢？
		System.out.println(c2);
		System.out.println("==============================");
		//因为ColleciontDemo02有好几条数据所以当前只可以删除最后的一条数据
		System.out.println("==============================");
		System.out.println(c1);
		System.out.println("==============================");
		c1.remove("TestCollection");
		c1.remove("CollectionDemo02");	 
		c1.remove("CollectionDemo02");	 
		c1.remove("CollectionDemo02");	 
		System.out.println(c1);
		System.out.println("==============================");
		
		//备注：容器类对象在调用remove，Collection 等方法时需要比较对象是否相等，这回涉及到对象类型的equals方法和hashCode方法，对于自定义的的类型
		//需要重写equals和hashCode方法以实现自定义的对象相等规则。
		System.out.println(c1.remove(new Desk("Office Desk 1","100","200")));	//false 
		
		
	}
}

class Desk {
	private String name;
	private String width;
	private String height;
	
	public Desk(String name,String width,String height) {
		this.name=name;
		this.width=width;
		this.height=height;
	}
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getWidth() {
		return width;
	}
	public void setWidth(String width) {
		this.width = width;
	}

	public String getHeight() {
		return height;
	}

	public void setHeight(String height) {
		this.height = height;
	}
	 
}