arraylist的使用

ArraylistDemo

package cn.stat.p6.arraylist.demo;
 
import java.util.ArrayList;
import java.util.Iterator;
 
import cn.stat.p5.person.demo.PresonDemo;
 
public class ArraylistDemo {
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
      ArrayList<PresonDemo> al=new ArrayList<PresonDemo>();
     PresonDemo p1=new PresonDemo("list1",11);
     PresonDemo p2=new PresonDemo("list2",12);
     PresonDemo p3=new PresonDemo("list3",13);
     al.add(p1);
     al.add(p2);
     al.add(p3);
      al.add(new PresonDemo("list5",15));
 
      Iterator<PresonDemo> it=al.iterator();
      while(it.hasNext())
      {
          PresonDemo p=(PresonDemo) it.next();
          System.out.println(p.getName()+";;"+p.getAge());
      }
      show(3);
 
      String qc="123";
      String ai="12";
      System.out.println(ai.hashCode());
      System.out.println(qc.hashCode());
 
    }
    public static void show(int i)
    {
        int s=i+1;
        System.out.println(s);
 
    }
 
}

PresonDemo

package cn.stat.p5.person.demo;
 
public class PresonDemo implements Comparable  {
 
    private String name;
    private int age;
 
    /**
     * @param args
     */
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    public void outPrint()
    {
 
        System.out.println(this.age+".."+this.name);
    }
    public PresonDemo(String name, int age) {
 
        this.name = name;
        this.age = age;
    }
    //TreeSet();为空时，实列类内部比较器
    @Override
    public int compareTo(Object o) {
        // TODO Auto-generated method stub
        PresonDemo p=(PresonDemo)o;
        if(p.age<this.age)
            return 1;
        if(p.age>this.age)
            return-1;
        return 0;
    }
 
}