以學生類為例，先準備一個Student類

package cn.sasa.demo1;

public class Student {
	private int id;
	private String name;
	
	public int getId() {
		return this.id;
	}
	public void setId(int id) {
		if(id<0) {
			this.id = 0;
		}else {
			this.id = id;
		}
	}

	public String getName() {
		return this.name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	public void SayHi() {
		System.out.println(this.id + "======" + this.name);
	}
}

　　測試類TestStudent:

package cn.sasa.demo1;
import java.util.ArrayList;
import java.util.Random;

public class TestStudent {

	public static void main(String[] args) {
		//要求隨機抽取三次，不重復
		ArrayList<Student> stuList = addStu();
		showStuList(stuList);
		
		getRanStu(stuList);
		showStuList(stuList);
		
		getRanStu(stuList);
		showStuList(stuList);
		
		getRanStu(stuList);
		showStuList(stuList);
	}

	public static ArrayList<Student> addStu() {
		ArrayList<Student> stuList = new ArrayList<Student>();
		Student s1 = new Student();
		s1.setId(1);
		s1.setName("abc");
		
		Student s2 = new Student();
		s2.setId(2);
		s2.setName("bcd");
		
		Student s3 = new Student();
		s3.setId(3);
		s3.setName("cde");
		
		Student s4 = new Student();
		s4.setId(4);
		s4.setName("def");
		
		Student s5 = new Student();
		s5.setId(5);
		s5.setName("efg");
		
		Student s6 = new Student();
		s6.setId(6);
		s6.setName("fgh");
		
		stuList.add(s1);
		stuList.add(s2);
		stuList.add(s3);
		stuList.add(s4);
		stuList.add(s5);
		stuList.add(s6);
		return stuList;
	}
	
	public static void showStuList(ArrayList<Student> stuList) {
		System.out.println("====================================");
		for(int i = 0; i < stuList.size(); i++) {
			stuList.get(i).SayHi();
		}
	}
	
	public static Student getRanStu(ArrayList<Student> stuList) {
		System.out.println("====================================");
		Random ran = new Random();
		int i = ran.nextInt(stuList.size());
		Student stu = stuList.get(i);
		stuList.remove(i);
		stu.SayHi();
		return stu;
	}
}

java 隨機抽取案例，不重復抽取