java：ArrayList循环遍历的俩种方法使用 ArrayList取出第i个值

package collection;

import java.util.*;

public class NewArrayList {

 public static void main(String[] args) {

  List<Student> students = new ArrayList<Student>();

  for (int i = 0; i < 6; i++) {

   students.add(new Student("Happy"+i,"male"+i,20+i));

  }

  print(students);

  print2(students);

 }

 

 //循环遍历①for

 public static void print(List<Student> newList){

  System.out.println("总数据："+newList.size());

  Student student;

  for (int i = 0; i < newList.size(); i++) {

   student = (Student)newList.get(i);

   System.out.println(student.toString());

  }

 }

 //循环遍历①Iterator

 public static void print2(List<Student> newList){

  System.out.println("总数据："+newList.size());

  Iterator<Student> iterator = newList.iterator();

  Student student;

  while (iterator.hasNext()){

   student = (Student)iterator.next();

   System.out.println(student.toString());

  }

 }

 

}

 

 

 

 

用List的成员函数get(int index)

index表示要取的元素的下标(从0开始)

例如:你想取第一个元素"201";

List grouplist=this.getGroupList();

String s =(String)grouplist.get(0);

此时s="201";

如果要循环输出:

for(int i=0;i<grouplist.size();i++)

System.out.println(grouplist.get(i));