java的arraylist排序示例(arraylist用法)
2015-10-14 17:52
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package com.yonyou.test; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; public class Test { public static void main(String[] args) { Student zlj = new Student("丁晓宇", 21); Student dxy = new Student("赵四", 22); Student cjc = new Student("张三", 11); Student lgc = new Student("刘武", 19); List<Student> studentList = new ArrayList<Student>(); studentList.add(zlj); studentList.add(dxy); studentList.add(cjc); studentList.add(lgc); System.out.println("按照年齡排序:"); Collections.sort(studentList, new SortByAge()); for (Student student : studentList) { System.out.println(student.getName() + " / " + student.getAge()); } System.out.println(" ========= "); System.out.println("按照姓名排序"); Collections.sort(studentList, new SortByName()); for (Student student : studentList) { System.out.println(student.getName() + " / " + student.getAge()); } } } class SortByAge implements Comparator { public int compare(Object o1, Object o2) { Student s1 = (Student) o1; Student s2 = (Student) o2; if (s1.getAge() > s2.getAge()) return 1; else if (s1.getAge() == s2.getAge()) { return 0; } return -1; } } class SortByName implements Comparator { public int compare(Object o1, Object o2) { Student s1 = (Student) o1; Student s2 = (Student) o2; if(s1.getName().compareTo(s2.getName()) < 0) return -1; else if (s1.getName().compareTo(s2.getName()) > 0) { return 1; } return 0; } } class Student{ private int age; private String name; public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Student(String name,int age) { this.age = age; this.name = name; } }
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