java中Collections.sort方法可以根据list中对象(或者map)的某个属性进行排序
import com.td.cms.entity.Question;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* Created by Jerry on 2017/2/7.
* God Bless Me
*/
public class test {
public static void main(String[] args) {
List<Question> questions = new ArrayList<>();
Question q1 = new Question();
Question q2 = new Question();
Question q3 = new Question();
q1.setQuesNum(1);
q2.setQuesNum(3);
q3.setQuesNum(2);
questions.add(q1);
questions.add(q2);
questions.add(q3);
Collections.sort(questions, new Comparator<Question>(){
/*
* int compare(Question o1, Question o2) 返回一个基本类型的整型,
* 返回负数表示:o1 小于o2,
* 返回0 表示:o1和o2相等,
* 返回正数表示:o1大于o2。
*/
public int compare(Question o1, Question o2) {
//按照学生的年龄进行升序排列
if(o1.getQuesNum() > o2.getQuesNum()){
return 1;
}
if(o1.getQuesNum() == o2.getQuesNum()){
return 0;
}
return -1;
}
});
for (Question question : questions) {
System.out.println(question.getQuesNum());
}
}
}