Java初学Text7---集合

1.编写一个新闻管理系统，可显示标题，创作者，实现id自增，可新增标题

package Week5NewsTitle;

import lombok.Data;
@Data
public class NewsTitle {

    private int ID=1;
    private String name;
    private String setters;

    public NewsTitle() {
    }

    public NewsTitle(int ID, String name, String setters) {
        this.ID = ID;
        this.name = name;
        this.setters = setters;
    }

    public NewsTitle( String name, String setters) {

        this.name = name;
        this.setters = setters;
    }

    public int getID() {
        return ID;
    }

    public void setID(int ID) {
        this.ID = ID;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSetters() {
        return setters;
    }

    public void setSetters(String setters) {
        this.setters = setters;
    }

    @Override
    public String toString() {
        return "NewsTitle{" +
                "ID=" + ID +
                ", name='" + name + ''' +
                ", setters='" + setters + ''' +
                '}';
    }
}

package Week5NewsTitle;

import java.util.ArrayList;
import java.util.List;

public class Demonews {
    public static List addNewsId(List list,NewsTitle newsTitle){
        int id=getNextId(list);
        newsTitle.setID(id);
        list.add(newsTitle);
        return list;
    }
    public static int getNextId(List list){
        if(list!=null){
            int ID=1;
            for (Object o:list) {
                NewsTitle a=(NewsTitle)o;
                if(a.getID()>=ID){
                    ID=a.getID()+1;
                }
            }
            return ID;
        }else{return 1;}

    }
    public static void main(String[] args) {
        NewsTitle n1=new NewsTitle(1,"中国日报","张三");
        NewsTitle n2=new NewsTitle(2,"时代周刊","李四");
        NewsTitle n3=new NewsTitle(5,"青年日报","王五");

        List list=new ArrayList();

        list.add(n1);
        list.add(n2);
        list.add(n3);
        NewsTitle n4= new NewsTitle();
        n4.setName("纽约时报");
        n4.setSetters("Jack");
        List newList=DemoNews.addNewsId(list,n4);

        System.out.println("-------------------------");
        System.out.println("共有"+list.size()+"条新闻");
        for (Object o2:list) {
            NewsTitle a=(NewsTitle)o2;
            System.out.println(a.getID()+" "+a.getName()+" "+a.getSetters());
        }
    }


}

运行结果：

 2.

package Week5NewsTitle;

import java.util.ArrayList;
import java.util.List;

public class DemoContain {
    public static boolean pd(List list,String s){
        if(list.isEmpty()){return false;}
        for (Object o:list) {
//            DefineContain a=(DefineContain)o;
             if(s.equals(o)){
                 return true;
             }
        }
        return false;
    }

    public static void main(String[] args) {
//        DefineContain d=new DefineContain();
//        d.setStr("aaa");
        List list=new ArrayList();
        list.add("aaa");
        list.add("abc");
        list.add("cba");
        boolean x=pd(list,"abc");
        System.out.println(x);
        System.out.println(list);
    }
}
    

 运行结果：