arraylist的使用

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;
}

}