Java中如何开发个人日记管理软件

 public class DiaryEntry {     private String title;     private String content;     private LocalDateTime date; <pre class='brush:java;toolbar:false;'>public DiaryEntry(String title, String content) {     this.title = title;     this.content = content;     this.date = LocalDateTime.now(); }  // Getter 和 Setter 方法 public String getTitle() { return title; } public void setTitle(String title) { this.title = title; }  public String getContent() { return content; } public void setContent(String content) { this.content = content; }  public LocalDateTime getDate() { return date; }  @Override public String toString() {     return "日期: " + date + "n标题: " + title + "n内容: " + content + "n"; }

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 import com.google.gson.Gson; import com.google.gson.reflect.TypeToken; import java.io.*; import java.util.ArrayList; <p>// 保存日记列表 public void saveEntries(ArrayList<DiaryEntry> entries, String filename) { try (FileWriter writer = new FileWriter(filename)) { new Gson().toJson(entries, writer); } catch (IOException e) { System.out.println("保存失败：" + e.getMessage()); } }</p><p>// 加载日记列表 public ArrayList<DiaryEntry> loadEntries(String filename) { try (FileReader reader = new FileReader(filename)) { return new Gson().fromJson(reader, new TypeToken<ArrayList<DiaryEntry>>(){}.getType()); } catch (FileNotFoundException e) { return new ArrayList<>(); // 文件不存在则返回空列表 } catch (IOException e) { System.out.println("读取失败：" + e.getMessage()); return new ArrayList<>(); } }</p>

 import java.util.*; <p>public class Diaryapp { private ArrayList<DiaryEntry> entries; private Scanner scanner; private static final String FILE_NAME = "diary.json";</p><pre class='brush:java;toolbar:false;'>public DiaryApp() {     entries = loadEntries(FILE_NAME);     scanner = new Scanner(System.in); }  public void start() {     while (true) {         System.out.println("n=== 个人日记系统 ===");         System.out.println("1. 写日记");         System.out.println("2. 查看所有日记");         System.out.println("3. 搜索日记");         System.out.println("4. 删除日记");         System.out.println("5. 退出");         System.out.print("请选择：");          int choice = scanner.nextInt();         scanner.nextLine(); // 消费换行符          switch (choice) {             case 1 -> writeDiary();             case 2 -> viewDiaries();             case 3 -> searchDiary();             case 4 -> deleteDiary();             case 5 -> {                 saveEntries(entries, FILE_NAME);                 System.out.println("已保存，再见！");                 return;             }             default -> System.out.println("无效选择，请重试。");         }     } }  private void writeDiary() {     System.out.print("请输入标题：");     String title = scanner.nextLine();     System.out.print("请输入内容：");     String content = scanner.nextLine();     entries.add(new DiaryEntry(title, content));     System.out.println("日记已保存！"); }  private void viewDiaries() {     if (entries.isEmpty()) {         System.out.println("暂无日记。");     } else {         for (int i = 0; i < entries.size(); i++) {             System.out.println("n--- 第" + (i+1) + "篇 ---");             System.out.println(entries.get(i));         }     } }  private void searchDiary() {     System.out.print("请输入关键词：");     String keyword = scanner.nextLine().toLowerCase();     boolean found = false;     for (DiaryEntry entry : entries) {         if (entry.getTitle().toLowerCase().contains(keyword) ||             entry.getContent().toLowerCase().contains(keyword)) {             System.out.println("n匹配结果：");             System.out.println(entry);             found = true;         }     }     if (!found) {         System.out.println("未找到相关日记。");     } }  private void deleteDiary() {     viewDiaries();     if (entries.isEmpty()) return;     System.out.print("输入要删除的序号：");     int index = scanner.nextInt() - 1;     if (index >= 0 && index < entries.size()) {         entries.remove(index);         System.out.println("删除成功！");     } else {         System.out.println("序号无效！");     } }  // 加载与保存方法见上文

 public static void main(String[] args) {     new DiaryApp().start(); } 

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