帮我优化以下代码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; } } }

这段代码主要有两个问题：

1. 没有使用 try-with-resources 语句处理文件流

2. 每次读取一行数据时，都需要进行字符串的操作，可能会影响性能

下面是我对代码进行的优化：

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) {
        ArrayList<Student> arr = new ArrayList<>();
        try (BufferedReader br = new BufferedReader(new FileReader("input.txt"));
             FileWriter writer = new FileWriter("output.txt")) {
            String msg;
            while ((msg = br.readLine()) != null) {
                if (msg.trim().isEmpty()) {
                    continue;
                }
                String[] stu = msg.split(" ");
                int num = Integer.parseInt(stu[0]);
                String na = stu[1];
                LocalDate da = LocalDate.parse(stu[2]);
                String gen = stu[3];
                Student student = new Student(num, na, da, gen);
                arr.add(student);
                Collections.sort(arr, Comparator.comparing(Student::getDate));
            }
            for (Student obj : arr) {
                writer.write(String.valueOf(obj));
                writer.write(System.lineSeparator());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    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;
        }
    }
}

优化后的代码使用 try-with-resources 语句处理文件流，避免了手动关闭流的问题。同时，将读取文件和写入文件的逻辑放在了同一个 try-with-resources 语句块中，避免了代码中的重复。读取文件时，使用了 `trim()` 方法去掉字符串两端的空格，并且使用 `isEmpty()` 方法判断是否为空，避免了每次读取数据时进行字符串判断的问题。写入文件时，使用了 `System.lineSeparator()` 方法代替了 `"\r\n"`，这样可以在不同的操作系统上保持一致的换行符。