Java基础之集合框架练习

痛定思痛。 2022-12-08 15:53 155阅读 0赞

package cn.itcast.p3.arraylist.test;
    
    import java.util.ArrayList;
    import java.util.Iterator;
    
    import cn.itcast.p.bean.Person;
    
    /*
     * 定义功能去除ArrayList中的重复元素。
     */
    
    public class ArrayListTest2 {
        
    
    	/**
    	 * @param args
    	 */
    	public static void main(String[] args) {
        
    		
    		
    //		demo();
    		
    //		singleDemo();
    		
    		
    		ArrayList al = new ArrayList();
    		al.add(new Person("lisi1",21));
    		al.add(new Person("lisi2",22));
    		al.add(new Person("lisi3",23));
    		al.add(new Person("lisi4",24));
    		al.add(new Person("lisi2",22));
    		al.add(new Person("lisi3",23));
    		System.out.println(al);
    		
    		al = getSingleElement(al);
    		
    		
    		System.out.println(al.remove(new Person("lisi2",22)));
    		System.out.println(al);
    		
    		
    		
    		
    	}
    
    	/**
    	 * 
    	 */
    	public static void singleDemo() {
        
    		ArrayList al = new ArrayList();
    		al.add("abc1");
    		al.add("abc2");
    		al.add("abc2");
    		al.add("abc1");
    		al.add("abc");
    		System.out.println(al);
    		
    		al = getSingleElement(al);
    		
    		System.out.println(al);
    		
    		
    	}
    
    	public static ArrayList getSingleElement(ArrayList al) {
        
    		
    		//1,定义一个临时容器。
    		ArrayList temp = new ArrayList();
    		
    		//2,迭代al集合。
    		Iterator it = al.iterator();
    		
    		while(it.hasNext()){
        
    			Object obj = it.next();
    			
    			//3,判断被迭代到的元素是否在临时容器存在。
    			if(!temp.contains(obj)){
        
    				temp.add(obj);
    			}
    		}
    		
    		return temp;
    	}
    
    	/**
    	 * 
    	 */
    	public static void demo() {
        
    		
    //		al.add(5);//al.add(new Integer(5));
    	}
    	
    
    }

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