对象数组与管理

朴灿烈づ我的快乐病毒、 2023-07-24 08:43 3阅读 0赞

### 对象数组与管理 ###

*   *  引入：
     *  例子

## 引入： ##

对象数组就是数组中的每个元素都是类的对象，赋值时先定义对象，然后将对象直接赋值给数组。

## 例子 ##

package no1;
    import java.util.Arrays;
    public class test10 {
        
    	public static void main(String[] args) {
        
    		ChickenManager cm = new ChickenManager(5);
    		//添加
    		cm.add(new Chicken(1,"小小",10));
    		cm.add(new Chicken(2,"小二",8));
    		cm.add(new Chicken(3,"小三",6));
    		cm.add(new Chicken(4,"小红",4));
    		cm.add(new Chicken(5,"小奋",2));
    		
    		cm.add(new Chicken(6,"小斗",1)); 
    		System.out.println("数组的长度为："+cm.length());
    		
    		System.out.println("-----printAll------");
    		cm.printAll();
    		System.out.println("-----find------");
    		Chicken c = cm.find(5);
    		c.print();
    		System.out.println("------update------");
    		cm.update(new Chicken(1,"下蛋铁公鸡",20));
    		cm.printAll();
    	}
    }
    
    //小鸡管理类
    class ChickenManager{
        
    	private Chicken[] cs = null;
    	private int count = 0;  //记录当前数组的元素个数（下标）
    	public ChickenManager(int size) {
        
    		if(size > 0) {
        
    			cs = new Chicken[size];
    		}else {
        
    			cs = new Chicken[5];
    		}
    	}
    	public int length() {
        
    		return cs.length;
    	}
    	//添加
    	public void add(Chicken c) {
        
    		if(count >= cs.length) {
        //数组已满，需要扩充
    			//1.扩充原来数组大小的一半 cs.length*3/2+1			
    			//2.扩充原来数组的一倍 cs.length*2
    			int newLen = cs.length<<1;
    			cs = Arrays.copyOf(cs, newLen);
    		}
    		cs[count] = c;
    		count++;
    	}
    	//删除
    	public void delete(int id) {
        
    		for(int i=0; i<count; i++) {
        
    			if(cs[i].getId() == id) {
        
    				for(int j=i; j<count-1; j++) {
        
    					cs[j] = cs[j+1];
    				}
    				cs[count-1] = null;
    				count--;
    				break;
    			}
    		}
    	}
    	//更新
    	public void update(Chicken c) {
        
    		Chicken temp = find(c.getId());
    		if(temp != null) {
        
    			temp.setName(c.getName());
    			temp.setAge(c.getAge());
    		}
    	}
    	//查找
    	public Chicken find(int id) {
         
    		for(int i=0; i<count; i++) {
        
    			if(cs[i].getId() == id) {
        
    				return cs[i];
    			}
    		}
    		return null;
    	}
    	//输出所有
    	public void printAll() {
        
    		for(int i=0; i<count; i++) {
        
    			cs[i].print();
    		}
    	}
    }
    
    //小鸡类（数据对象）
    class Chicken{
        
    	private int id;
    	private String name;
    	private int age;
    	public Chicken() {
        };
    	public Chicken(int id,String name, int age) {
        
    		this.id = id;
    		this.name = name;
    		this.age = age;
    	}
    	public void setId(int id) {
        
    		this.id = id;
    	}
    	public void setAge(int age) {
        
    		this.age = age;
    	}
    	public void setName(String name) {
        
    		this.name = name;
    	}
    	public int getId() {
        
    		return id;
    	}
    	public int getAge() {
        
    		return age;
    	}
    	public String getName() {
        
    		return name;
    	}
    	public void print() {
        
    		System.out.println("id=" + id + ",name=" + name+ ",age="+age);
    	}
    }