将下列Java代码改为python代码：import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.concurrent.CountDownLatch; import java.net.*; public class Scanport { public static void main(String[] args) throws InterruptedException { String host = "120.46.209.149"; int startPort = 1; int endPort = 1024; int start = 0; int end = 0; int step = Math.round(endPort / 1000) + 1;// 四舍五入函数 for (int i = 1; i < step; i++) { start = startPort + (i - 1) * 1000; end = startPort + i * 1000; System.out.println("正在扫描" + start + "-" + end); scan(host, start, end); } } public static void scan(String host, int startPort, int endPort) throws InterruptedException { List<Integer> portList = new ArrayList<>(); final CountDownLatch latch = new CountDownLatch(endPort - startPort + 1); for (int port = startPort; port <= endPort; port++) { int finalPort = port; Thread thread = new Thread(new Runnable() { @Override public void run() { try { Socket socket = new Socket(); socket.connect(new InetSocketAddress(host, finalPort), 100); System.out.println("TCP端口" + finalPort + "开放"); portList.add(finalPort); } catch (Exception e) { } try { DatagramSocket dsocket = new DatagramSocket(finalPort); dsocket.close(); } catch (SocketException e) { portList.add(finalPort); System.out.println("UDP端口" + finalPort + "开放"); } latch.countDown(); } }); thread.start(); } latch.await(); portList.sort(new Comparator<Integer>() { @Override public int compare(Integer o1, Integer o2) { return o1.compareTo(o2); } }); } }

import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; public class Student { private String name; private int age; private int chinesescore; private int mathsscore; private int englishscore; public Student(String name, int age, int chinesescore, int mathsscore, int englishscore) { this.name = name; this.age = age; this.chinesescore = chinesescore; this.mathsscore = mathsscore; this.englishscore = englishscore; } public String getName() { return name; } public int getAge() { return age; } public int getch() { return chinesescore; } public int getma() { return mathsscore; } public int geteng() { return englishscore; } public int gettotal() { return englishscore + chinesescore + mathsscore; } public void printScores() { System.out.println(getName()); System.out.println(getAge()); System.out.println(getch()); System.out.println(getma()); System.out.println(geteng()); } public static void main(String[] args) { Student student1 = new Student("张三", 18, 80, 90, 85); Student student2 = new Student("李四", 17, 75, 95, 90); Student student3 = new Student("王五", 16, 85, 80, 95); student1.printScores(); student2.printScores(); student3.printScores(); } List<Student> students = new ArrayList<>(); Comparator<Student> comparator = Comparator.comparing(Student::gettotal) .reversed() .thenComparing(Student::getch, Comparator.reverseOrder()) .thenComparing(Student::getma, Comparator.reverseOrder()) .thenComparing(Student::getAge); Collections.sort(student, comparator); for (Student student : students) { System.out.println(student); } }

请将代码中的student改为students，如下所示： java Collections.sort(students, comparator); for (Student student : students) { System.out.println(student); } 这样就可以正确地对学生对象进行排序...

将下列java代码改为python代码：import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.concurrent.CountDownLatch; import java.net.; public class Scanport { public static void main(String[] args) throws InterruptedException { String host = "120.46.209.149"; int startPort = 1; int endPort = 1024; int start = 0; int end = 0; int step = Math.round(endPort / 1000) + 1;// 四舍五入函数 for (int i = 1; i < step; i++) { start = startPort + (i - 1) 1000; end = startPort + i * 1000; System.out.println("正在扫描" + start + "-" + end); scan(host, start, end); } } public static void scan(String host, int startPort, int endPort) throws InterruptedException { List<Integer> portList = new ArrayList<>(); final CountDownLatch latch = new CountDownLatch(endPort - startPort + 1); for (int port = startPort; port <= endPort; port++) { int finalPort = port; Thread thread = new Thread(new Runnable() { @Override public void run() { try { Socket socket = new Socket(); socket.connect(new InetSocketAddress(host, finalPort), 100); System.out.println("TCP端口" + finalPort + "开放"); portList.add(finalPort); } catch (Exception e) { } try { DatagramSocket dsocket = new DatagramSocket(finalPort); dsocket.close(); } catch (SocketException e) { portList.add(finalPort); System.out.println("UDP端口" + finalPort + "开放"); } latch.countDown(); } }); thread.start(); } latch.await(); portList.sort(new Comparator<Integer>() { @Override public int compare(Integer o1, Integer o2) { return o1.compareTo(o2); } }); } }

以下是将Java代码转换为Python代码的结果： import socket import threading from queue import Queue def scan(host, startPort, endPort): port_list = [] for port in range(startPort, endPort + 1): ...

将下列代码改为python代码：import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.concurrent.CountDownLatch; import java.net.; public class Scanport { public static void main(String[] args) throws InterruptedException { String host = "120.46.209.149"; int startPort = 1; int endPort = 1024; int start = 0; int end = 0; int step = Math.round(endPort / 1000) + 1;// 四舍五入函数 for (int i = 1; i < step; i++) { start = startPort + (i - 1) 1000; end = startPort + i * 1000; System.out.println("正在扫描" + start + "-" + end); scan(host, start, end); } } public static void scan(String host, int startPort, int endPort) throws InterruptedException { List<Integer> portList = new ArrayList<>(); final CountDownLatch latch = new CountDownLatch(endPort - startPort + 1); for (int port = startPort; port <= endPort; port++) { int finalPort = port; Thread thread = new Thread(new Runnable() { @Override public void run() { try { Socket socket = new Socket(); socket.connect(new InetSocketAddress(host, finalPort), 100); System.out.println("TCP端口" + finalPort + "开放"); portList.add(finalPort); } catch (Exception e) { } try { DatagramSocket dsocket = new DatagramSocket(finalPort); dsocket.close(); } catch (SocketException e) { portList.add(finalPort); System.out.println("UDP端口" + finalPort + "开放"); } latch.countDown(); } }); thread.start(); } latch.await(); portList.sort(new Comparator<Integer>() { @Override public int compare(Integer o1, Integer o2) { return o1.compareTo(o2); } }); } }

import socket import threading def scan(host, startPort, endPort): portList = [] for port in range(startPort, endPort+1): thread = threading.Thread(target=checkPort, args=(host, port, portList)) ...

import java.util.Scanner; import java.util.ArrayList; import java.util.Comparator; public class Main { public static void main(String []args) { Scanner in = new Scanner(System.in); int n = Integer.parseInt(in.nextLine()); ArrayList<String> a = new ArrayList<String>(); while(n!=0){ String s = in.nextLine(); if(!a.contains(s)){ a.add(s); } n--; } a.sort(new Comparator<String>() { @Override public int compare(String s1, String s2) { return Integer.parseInt(s1.substring(0, 4))-Integer.parseInt(s2.substring(0, 4)); } }); System.out.println(a.size()); for(String i:a){ System.out.println(i); } } }

这是一段使用Java语言编写的程序。程序的功能是读取用户输入的一组字符串，去除其中重复的字符串，并按照字符串前四个字符转换成的整数从小到大排序，最后输出排序后的字符串列表。具体实现方法是先使用Scanner类...

import java.util.Scanner; import java.util.Arrays; import java.util.Comparator; import java.util.List; import java.util.ArrayList; import java.util.stream.Collectors; class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int numberOfWineshops = scanner.nextInt(); int numberOfPickedWineshops = scanner.nextInt(); int referencePrice = scanner.nextInt(); int[] WineshopPrices = new int[numberOfWineshops]; for (int i = 0; i < numberOfWineshops; i++) { WineshopPrices[i] = scanner.nextInt(); } Arrays.sort(WineshopPrices); int[][] priceDifference = new int[numberOfWineshops][2]; for (int i = 0; i < numberOfWineshops; i++) { int price = WineshopPrices[i]; priceDifference[i][0] = price; priceDifference[i][1] = Math.abs(price - referencePrice); } List<int[]> sortedPriceDifference = Arrays.stream(priceDifference) .sorted(Comparator.comparingInt(Wineshop -> Wineshop[1])) .collect(Collectors.toList()); List<Integer> pickedWineshopPrices = new ArrayList<>(); for (int i = 0; i < numberOfPickedWineshops; i++) { pickedWineshopPrices.add(sortedPriceDifference.get(i)[0]); } pickedWineshopPrices.sort(Integer::compareTo); for (int i = 0; i < pickedWineshopPrices.size(); i++) { System.out.print(pickedWineshopPrices.get(i)); if (i != pickedWineshopPrices.size() - 1) { System.out.print(" "); } } } }；这段代码每行注释下

import java.util.Comparator; // 引入Comparator接口 import java.util.List; // 引入List接口 import java.util.ArrayList; // 引入ArrayList类 import java.util.stream.Collectors; // 引入Collectors类 class ...

import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.stream.Collectors; public class BookTest { public static void main(String[] args) { List<Book> books = new ArrayList<>(); // 初始化5本图书 books.add(new Book("Java编程思想", "Bruce Eckel", 2007, 89.5)); books.add(new Book("Effective Java", "Joshua Bloch", 2018, 105.0)); books.add(new Book("深入理解JVM", "周志明", 2020, 75.0)); books.add(new Book("设计模式", "Joshua Bloch", 1994, 55.5)); books.add(new Book("算法导论", "Thomas", 2009, 120.0)); System.out.println("=== 原始书籍列表 ==="); printBooks(books); // 删除书籍 removeBookByTitle(books, "算法导论"); System.out.println("\n=== 删除后书籍列表 ==="); printBooks(books); // 排序（按价格降序） books.sort(Comparator.comparingDouble(Book::getPrice).reversed()); System.out.println("\n=== 按价格降序排序 ==="); printBooks(books); // 查找作者书籍 String targe

import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.stream.Collectors; class Book { private String title; private String author; private int year; ...

帮我解释以下代码import java.io.*; import java.time.LocalDate; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; public class Demo5 { public static void main(String[] args) throws IOException { ArrayList<Student> arr = new ArrayList<>(); File f1 = new File("input.txt"); FileInputStream fin = new FileInputStream(f1); BufferedReader br = new BufferedReader(new InputStreamReader(fin)); String msg = br.readLine(); while (msg != null) { if (msg.equals("")) { msg = br.readLine(); continue; } String[] stu = msg.split(" "); String num = stu[0]; String na = stu[1]; String da = stu[2]; String gen = stu[3]; Student student = new Student(Integer.parseInt(num), na,LocalDate.parse(da), gen); arr.add(student); Collections.sort(arr,Comparator.comparing(Student::getDate)); msg = br.readLine(); } br.close(); fin.close(); FileWriter writer = new FileWriter("output.txt"); for (Student obj:arr ) { writer.write(String.valueOf(obj)); writer.write("\r\n"); } writer.close(); } static class Student { private Integer number; private String name; private LocalDate date; private String gender; public LocalDate getDate() { return date; } public Student(Integer number, String name, LocalDate date, String gender) { this.number = number; this.name = name; this.date = date; this.gender = gender; } @Override public String toString() { return number + " " + name + " " + date + " " + gender; } } }

2. 将读取的学生信息存储在一个ArrayList中，每个元素为一个Student对象。 3. 对ArrayList中的学生对象按照出生日期进行排序。 4. 将排好序的学生信息写入名为"output.txt"的文件中，每行为一名学生的信息，格式与...

以下代码的输出结果是什么？package Day06; import javafx.print.Collation; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; public class CustDemo { public static void main(String[] args) { addCustInfo("张三"); addInger(123); addall("小胡","老张"); isLastNull(""); sort(); } private static void addCustInfo(String name){ ArrayList<Cust> custs=new ArrayList<>(); Cust cust=new Cust(); cust.setCustName(name); custs.add(cust); System.out.println(custs.get(0).getCustName()); System.out.println("集合的大小为："+custs.size()); } private static void addInger(int age){ ArrayList<Integer>integers=new ArrayList<>(); integers.add(age); System.out.println(integers.get(0)); System.out.println("集合的大小为："+integers.size()); } private static void addall(String name,String name2){ ArrayList<String >strings=new ArrayList<>(); strings.add(name); ArrayList<String> strings1=new ArrayList<>(); strings1.add(name2); strings.addAll(strings1); for(String str:strings){ System.out.println(str); } System.out.printf("----->\n"); System.out.println(strings.get(1)); } private static void isLastNull(String name){ ArrayList<String >strings=new ArrayList<>(); strings.add(name); if(strings.size()>0){ System.out.println("非空"); }else { System.out.println("空"); } if(strings.isEmpty()){ System.out.println("空"); }else { System.out.println("非空"); } } private static void sort(){ ArrayList<Integer >integers=new ArrayList<>(); integers.add(1); integers.add(5); integers.add(3); integers.add(9); integers.add(7); integers.sort(Comparator.naturalOrder());//小到大排序顺序 System.out.println(integers); System.out.println("----->"); integers.sort(Comparator.reverseOrder());//大到小排序倒序 System.out.println(integers); System.out.println("----->"); Collections.sort(integers);//正序排序 System.out.println(integers); System.out.println("----->"); int y=1; for (Integer num:integers){ System.out.printf("序号为%d:",y); y++; System.out.println(num); } } // private void sunList(){ // // } }

接着，isLastNull("") 方法将空字符串添加到 ArrayList<String> 集合中，并通过判断集合大小和是否为空来输出结果。最后，sort() 方法演示了对 ArrayList<Integer> 集合进行排序的几种方式。首先，使用 ...

某教务管理系统中一个班级(Classes)包含多个学生(Student)，使用Java内置迭代器实现对学生信息遍历，要求按学生年龄由小到大的次序输出学生信息。比较器：接口java.lang.Comparable 和java.util.Comparator

import java.util.ArrayList; import java.util.List; public class Classes { private List<Student> students; // 构造函数和getter方法 public void printStudentsByAge() { Collections.sort(students); ...

dataList.sort( Comparator.comparing( ShopeePushOrderDto::getOrderProfit, Comparator.nullsLast(Comparator.reverseOrder()) ) ); orderProfit这个字段有可能正值，负值，空，现在负值之间没有倒序

import java.util.ArrayList; import java.util.List; class ListNode { int val; ListNode next; ListNode(int x) { val = x; } } public class ReverseLinkedList { public int[] reversePrint(ListNode ...

x = int(input()) li = [] for i in range(x): temp = list(map(str, input().split(" - "))) li.append(temp) def time_to_seconds(time_str): h, m, s = map(int, time_str.split(":")) return h * 3600 + m * 60 + s li.sort(key=lambda item: time_to_seconds(item[1])) re=[] if not li[0][0]=="00:00:00": re.append(["00:00:00",li[0][0]]) for i in range(len(li)-1): if(li[i][1]!=li[i+1][0]): re.append([li[i][1],li[i+1][0]]) if not li[len(li)-1][1]=="23:59:59": re.append([li[len(li)-1][1],"23:59:59"]) for i in re: print(i[0]+" - "+i[1])package L2; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.; public class LaoBanDeZuoXiBiao { public static void main(String[] args) throws IOException { BufferedReader bf=new BufferedReader(new InputStreamReader(System.in)); int x=Integer.valueOf(bf.readLine()); String[][]da=new String[x][2]; for(int i=0;i<x;i++){ String[]s=bf.readLine().split(" - "); da[i]=s; } Comparator<String[]>com=new Comparator<String[]>() { @Override public int compare(String[] o1, String[] o2) { int[] array = Arrays.stream(o1[1].split(":")).mapToInt(Integer::parseInt).toArray(); int[] array2 = Arrays.stream(o2[1].split(":")).mapToInt(Integer::parseInt).toArray(); int x=array[0]3600+array[1]60+array[2]; int x2=array2[0]3600+array2[1]*60+array2[2]; return x-x2; } }; Arrays.sort(da,com); ArrayList<String[]>re=new ArrayList<String[]>(); if(!da[0][0].equals("00:00:00")){ String[]temp={"00:00:00",da[0][0]}; re.add(temp); } for(int i=0;i<=da.length-2;i++){ if(!da[i][1].equals(da[i+1][0])){ String[] temp={da[i][1],da[i+1][0]}; re.add(temp); } } if(!da[da.length-1][1].equals("23:59:59")){ String[] temp={da[da.length-1][1],"23:59:59"}; re.add(temp); } for(String[] ss:re){ System.out.println(ss[0]+" - "+ss[1]); } } } 以上两种代码原理算法思想都是一样，只不过语法不同，为啥python时间短，Java时间长

例如，如果Java的Comparator改为先为每个元素预计算时间（类似于Python的key），然后比较这些预计算的值，那么排序时间应该会减少。这样可以避免在每次比较时重复解析字符串，提升性能。另外，用户可能没有考虑到...

对这段代码进行改错import java.io.; import java.util.; public class Test { public static void main(String[] args) throws IOException, ClassNotFoundException { List<Student> students = new ArrayList<>(); students.add(new Student("001", "张三", 90)); students.add(new Student("002", "李四", 80)); students.add(new Student("003", "王五", 85)); students.add(new Student("004", "赵六", 95)); // 排序并保存到文件 Collections.sort(students); ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("stud.dat")); out.writeObject(students); out.close(); // 从文件读取并显示学生信息 ObjectInputStream in = new ObjectInputStream(new FileInputStream("stud.dat")); List<Student> sortedStudents = (List<Student>) in.readObject(); for (Student student : sortedStudents) { System.out.println(student); } in.close(); } }

这段代码本身没有错误，但是需要注意以下几点： 1. Student类必须实现Serializable接口，以便可以使用ObjectOutputStream将对象序列化到文件中，和使用ObjectInputStream从文件中反序列化对象。 2. 如果...

package step3; import java.util.Map; import java.util.HashMap; import java.util.StringTokenizer; public class StudentDemo{ //获取单词的数量 public Map<String, Integer> getWordCount(String str) { Map<String, Integer> map = new HashMap<String, Integer>(); //请在此添加实现代码 / Begin / / End / return map; } } 请仔细阅读右侧代码，根据方法内的提示，在Begin - End区域内进行代码补充，具体任务如下：将指定文本(可以通过右侧文件目录下的src/step3/readme.txt查看)以降序的方式输出每个单词出现的次数。

import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; List<Map.Entry, Integer>> list = new ArrayList(wordCountMap.entrySet()); Collections.sort...

编程要求请仔细阅读右侧代码，根据方法内的提示，在Begin - End区域内进行代码补充，具体任务如下：将指定文本(可以通过右侧文件目录下的src/step3/readme.txt查看)以降序的方式输出每个单词出现的次数。package step3; import java.util.Map; import java.util.HashMap; import java.util.StringTokenizer; public class StudentDemo{ //获取单词的数量 public Map<String, Integer> getWordCount(String str) { Map<String, Integer> map = new HashMap<String, Integer>(); //请在此添加实现代码 / Begin / / End / return map; } }

import java.util.*; import java.io.*; public class WordFrequencyCounter { public static void main(String[] args) throws IOException { String text = "Your text content here"; // 替换为实际文本或文件...

package L2; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.*; public class LaoBanDeZuoXiBiao { public static void main(String[] args) throws IOException { BufferedReader bf=new BufferedReader(new InputStreamReader(System.in)); int x=Integer.valueOf(bf.readLine()); String[][]da=new String[x][2]; for(int i=0;i<x;i++){ String[]s=bf.readLine().split(" - "); da[i]=s; } Comparator<String[]>com=new Comparator<String[]>() { @Override public int compare(String[] o1, String[] o2) { return o1[1].compareTo(o2[1]); } }; Arrays.sort(da,com); ArrayList<String[]>re=new ArrayList<String[]>(); if(!da[0][0].equals("00:00:00")){ String[]temp={"00:00:00",da[0][0]}; re.add(temp); } for(int i=0;i<=da.length-2;i++){ if(!da[i][1].equals(da[i+1][0])){ String[] temp={da[i][1],da[i+1][0]}; re.add(temp); } } if(!da[da.length-1][1].equals("23:59:59")){ String[] temp={da[da.length-1][1],"23:59:59"}; re.add(temp); } for(String[] ss:re){ System.out.println(ss[0]+" - "+ss[1]); } } } 针对于这段代码，在时间复杂度上还能做哪些优化

嗯，我现在需要分析用户提供的Java代码，并思考在时间复杂度上还能做哪些优化。首先，我得先理解这段代码的功能和结构。这段代码的主要功能是处理时间段数据，找出未被覆盖的时间段。用户输入一组时间段，程序将...

package com.shanzhu.tourism.utils.recommend; import cn.hutool.core.collection.CollUtil; import cn.hutool.core.map.MapUtil; import com.google.common.collect.Lists; import com.shanzhu.tourism.utils.recommend.dto.RelateDTO; import java.util.*; import java.util.stream.Collectors; import java.util.stream.IntStream; /** * 推荐算法 * * @author: ShanZhu * @date: 2024-07-25 */ public class CoreMath { /** * 推荐计算 */ public List<String> recommend(String userId, List<RelateDTO> list) { //找到最近邻用户id Map<Double, String> distances = computeNearestNeighbor(userId, list); if(MapUtil.isEmpty(distances)){ return Collections.EMPTY_LIST; } //取出相似度最近的用户id String nearest = distances.values().iterator().next(); Iterator<String> iterator = distances.values().iterator(); while (iterator.hasNext()) { nearest = iterator.next(); } Map<String, List<RelateDTO>> userMap = list.stream().collect(Collectors.groupingBy(RelateDTO::getUserId)); //最近邻用户涉及的业务id列表 List<String> neighborItemList = userMap.get(nearest).stream().map(e -> e.getProductId()).collect(Collectors.toList()); //当前用户涉及的业务id列表 List<String> userItemList = userMap.get(userId).stream().map(e -> e.getProductId()).collect(Collectors.toList()); //找到最近邻买过，但是该用户没涉及过的，计算推荐，放入推荐列表 List<String> recommendList = new ArrayList<>(); for (String item : neighborItemList) { if (!userItemList.contains(item)) { recommendList.add(item); } } Collections.sort(recommendList); return recommendList; } /** * 在给定userId的情况下，计算其他用户和它的相关系数并排序 */ private Map<Double, String> computeNearestNeighbor(String userId, List<RelateDTO> list) { //对同一个用户id数据，做分组 Map<String, List<RelateDTO>> userMap = list.stream().collect(Collectors.groupingBy(RelateDTO::getUserId)); //treemap是从小到大排好序的

用java调用python

java在web程序具有很大的优势，然而在科学计算，机器学习等领域中不如python，使用java调用python就是为了能够使得一个问题能够更好的解决。

相关推荐

java2python, 将Java源代码转换为 python的简单但有效的库.zip

java_to_python:使用python代码将Java

Java中调用Python代码

某教务管理系统中一个班级(Classes)包含多个学生(Student)，使用Java内置迭代器实现对学生信息遍历，要求按学生年龄由小到大的次序输出学生信息。 比较器：接口java.lang.Comparable 和java.util.Comparator

dataList.sort( Comparator.comparing( ShopeePushOrderDto::getOrderProfit, Comparator.nullsLast(Comparator.reverseOrder()) ) ); orderProfit这个字段有可能正值，负值，空，现在负值之间没有倒序

用java调用python

大家在看

matlab source code of GA for urban intersections green wave control

dmm fanza better -crx插件

服务质量管理-NGBOSS能力架构

AUTOSAR_MCAL_WDG.zip

基于tensorflow框架，用训练好的Vgg16模型，实现猫狗图像分类的代码.zip

最新推荐

Java Collections.sort()实现List排序的默认方法和自定义方法

Java针对ArrayList自定义排序的2种实现方法

java ArrayList集合中的某个对象属性进行排序的实现代码

构建基于ajax, jsp, Hibernate的博客网站源码解析

【Unity Sunny Land关卡设计高级指南】：打造完美关卡的8大技巧

C++ 模版

C#随机数摇奖系统功能及隐藏开关揭秘

【数据驱动的力量】：管道缺陷判别方法论与实践经验

EditPlus中实现COBOL语言语法高亮的设置

某教务管理系统中一个班级(Classes)包含多个学生(Student)，使用Java内置迭代器实现对学生信息遍历，要求按学生年龄由小到大的次序输出学生信息。比较器：接口java.lang.Comparable 和java.util.Comparator