update:demo6

.gitignore

@@ -0,0 +1,95 @@
+### Compiled class files
+*.class
+
+### Log files
+*.log
+
+### BlueJ files
+*.ctxt
+
+### Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+### Package Files
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+### VM crash logs
+hs_err_pid*
+replay_pid*
+
+# ========================
+# Maven
+# ========================
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+.mvn/wrapper/maven-wrapper.jar
+
+# ========================
+# Gradle
+# ========================
+.gradle/
+build/
+!gradle-wrapper.jar
+!*/src/main/**/build/
+!*/src/test/**/build/
+
+### Avoid ignoring Gradle wrapper
+gradle-app.setting
+
+# ========================
+# IntelliJ IDEA
+# ========================
+.idea/
+*.iml
+*.ipr
+*.iws
+out/
+
+# ========================
+# Eclipse
+# ========================
+.project
+.classpath
+.cproject
+.settings/
+bin/
+tmp/
+
+# ========================
+# NetBeans
+# ========================
+nbproject/private/
+nbbuild/
+dist/
+nbdist/
+.nb-gradle/
+
+# ========================
+# VS Code
+# ========================
+.vscode/
+
+# ========================
+# OS files
+# ========================
+# macOS
+.DS_Store
+
+# Windows
+Thumbs.db
+
+#local
+com/study/test/

com/study/demo/Demo.java

@@ -1,7 +1,7 @@
 package com.study.demo;
 
 public class Demo {
-	public static void main(String [] args) {
+  public static void main(String[] args) {
     System.out.println("HelloWorld!");
   }
 }

com/study/demo/test1_1.java

@@ -1,9 +1,11 @@
 package com.study.demo;
+
 import java.util.Scanner;
+
 // I am 212306206
 public class test1_type {
   public static void main(String[] args) {
-		Scanner scanner = new Scanner (System.in);
+    Scanner scanner = new Scanner(System.in);
     int a = scanner.nextInt();
     int b = scanner.nextInt();
     int sum = a + b;

com/study/demo/test1_2.java

@@ -13,4 +13,3 @@ public class test2_for {
     }
   }
 }
-

com/study/demo/test1_3.java

@@ -16,4 +16,3 @@ public class test3_1_99 {
     System.out.println("1+2+...+99 的和 = " + sum);
   }
 }
-

com/study/demo/test2_2.java

@@ -1,4 +1,5 @@
 package com.study.demo;
+
 import java.util.Scanner;
 
 public class test5 {

com/study/demo2/Animal.java

@@ -8,6 +8,7 @@ public abstract class Animal {
   }
 
   public abstract void makeSound();
+
   public abstract void move();
 }
 

com/study/demo2/Rectangle.java

@@ -4,7 +4,8 @@ public class Rectangle {
   private double width = 1.0;
   private double height = 1.0;
 
-    public Rectangle() {}
+  public Rectangle() {
+  }
 
   public Rectangle(double width, double height) {
     this.width = width;

com/study/demo2/Student.java

@@ -24,17 +24,23 @@ public class Student {
   public int getMaxScore() {
     int max = score[0];
     for (int s : score) {
-            if (s > max) max = s;
+      if (s > max)
+        max = s;
     }
     return max;
   }
 
   public char getGrade() {
     double avg = getAverage();
-        if (avg >= 90) return 'A';
+    if (avg >= 90)
-        else if (avg >= 80) return 'B';
+      return 'A';
-        else if (avg >= 70) return 'C';
+    else if (avg >= 80)
-        else if (avg >= 60) return 'D';
+      return 'B';
-        else return 'E';
+    else if (avg >= 70)
+      return 'C';
+    else if (avg >= 60)
+      return 'D';
+    else
+      return 'E';
   }
 }

com/study/demo2/Student_Main.java

@@ -2,9 +2,8 @@ package com.study.demo2;
 
 public class Main {
   public static void main(String[] args) {
-        int[] scores = {85, 90, 78, 92, 88, 76, 95, 89, 79, 94};
+    int[] scores = { 85, 90, 78, 92, 88, 76, 95, 89, 79, 94 };
     Student student = new Student("5001", "张三", scores);
-        
     System.out.println("平均分: " + student.getAverage());
     System.out.println("最高分: " + student.getMaxScore());
     System.out.println("等级: " + student.getGrade());

com/study/demo3/Bicycle.java

@@ -1,4 +1,5 @@
 package com.study.demo3;
+
 public class Bicycle extends Vehicle {
   @Override
   public void start() {

com/study/demo3/Book.java

@@ -5,26 +5,22 @@ public class Book {
   protected String title;
   protected boolean available;
 
-   
   public Book() {
     this.available = true;
   }
 
-   
   public Book(String isbn, String title) {
     this.isbn = isbn;
     this.title = title;
     this.available = true;
   }
 
-   
   public Book(String isbn, String title, boolean available) {
     this.isbn = isbn;
     this.title = title;
     this.available = available;
   }
 
-   
   public String getIsbn() {
     return isbn;
   }
@@ -49,11 +45,11 @@ public class Book {
     this.available = available;
   }
 
-   
   public void returnBook() {
     if (!this.available) {
       this.available = true;
-            System.out.println(this.title + " (ISBN: " + this.isbn + ") has been returned and is now available.");
+      System.out.println(
+          this.title + " (ISBN: " + this.isbn + ") has been returned and is now available.");
     } else {
       System.out.println(this.title + " (ISBN: " + this.isbn + ") is already available.");
     }

com/study/demo3/Car.java

@@ -1,7 +1,7 @@
 package com.study.demo3;
+
 public class Car extends Vehicle {
   @Override
-   
   public void start() {
     System.out.println("The car is started");
   }

com/study/demo3/EBook.java

@@ -1,20 +1,17 @@
 package com.study.demo3;
+
 public class EBook extends Book {
   private double fileSize;
 
-   
   public EBook() {
     super();
   }
 
-   
-   
   public EBook(String isbn, String title, double fileSize) {
     super(isbn, title);
     this.fileSize = fileSize;
   }
 
-   
   public double getFileSize() {
     return fileSize;
   }
@@ -25,6 +22,14 @@ public class EBook extends Book {
 
   @Override
   public String toString() {
-        return "EBook [ISBN=" + isbn + ", Title=" + title + ", FileSize=" + fileSize + "MB, Available=" + available + "]";
+    return "EBook [ISBN="
+        + isbn
+        + ", Title="
+        + title
+        + ", FileSize="
+        + fileSize
+        + "MB, Available="
+        + available
+        + "]";
   }
 }

com/study/demo3/Library.java

@@ -1,8 +1,9 @@
 package com.study.demo3;
+
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.ArrayList;
 
 public class Library {
 
@@ -12,12 +13,9 @@ public class Library {
     this.books = new HashMap<>();
   }
 
-   
-   
   public void addBook(Book b) {
     String isbn = b.getIsbn();
 
-       
     if (books.containsKey(isbn)) {
       System.out.println("The book already exists, adding it failed.");
     } else {
@@ -26,12 +24,9 @@ public class Library {
     }
   }
 
-   
-   
   public List<Book> searchAvailableBooks() {
     List<Book> availableBooks = new ArrayList<>();
 
-       
     for (Book book : books.values()) {
       if (book.isAvailable()) {
         availableBooks.add(book);

com/study/demo3/LibraryTest.java

@@ -1,26 +1,22 @@
 package com.study.demo3;
+
 import java.util.List;
 
 public class LibraryTest {
   public static void main(String[] args) {
     Library lib = new Library();
 
-       
     EBook e1 = new EBook("E001", "Java Basics", 5.2);
 
     e1.setAvailable(false);
 
-       
     PrintedBook p1 = new PrintedBook("P001", "Design Patterns", 3);
 
-       
     lib.addBook(e1);
     lib.addBook(p1);
 
-       
     lib.addBook(p1);
 
-       
     System.out.println("\n--- 可借阅图书列表 (available = true) ---");
     List<Book> availableList = lib.searchAvailableBooks();
 
@@ -33,7 +29,6 @@ public class LibraryTest {
       }
     }
 
-       
     e1.returnBook();
     System.out.println("\n--- 恢复 e1 后可借阅图书列表 ---");
     availableList = lib.searchAvailableBooks();

com/study/demo3/Main3.java

@@ -1,4 +1,5 @@
 package com.study.demo3;
+
 public class Main {
   public static void main(String[] args) {
 
@@ -7,15 +8,12 @@ public class Main {
     EBook ebook = new EBook("123-456", "Java Programming", 2.5);
     System.out.println("EBook Status (Initial): " + ebook.toString());
 
-       
     ebook.setAvailable(false);
     System.out.println("EBook Status (Borrowed): " + ebook.toString());
 
-       
     ebook.returnBook();
     System.out.println("EBook Status (After Return): " + ebook.toString());
 
-       
     System.out.println("\n--- 测试 PrintedBook ---");
     PrintedBook pbook = new PrintedBook();
     pbook.setIsbn("789-012");
@@ -23,11 +21,9 @@ public class Main {
     pbook.setStock(10);
     System.out.println("PBook Status (Initial): " + pbook.toString());
 
-       
     pbook.setAvailable(false);
     System.out.println("PBook Status (Borrowed): " + pbook.toString());
 
-       
     pbook.returnBook();
     System.out.println("PBook Status (After Return): " + pbook.toString());
   }

com/study/demo3/PrintedBook.java

@@ -1,19 +1,17 @@
 package com.study.demo3;
+
 public class PrintedBook extends Book {
   private int stock;
 
-   
   public PrintedBook() {
     super();
   }
 
-   
   public PrintedBook(String isbn, String title, int stock) {
     super(isbn, title);
     this.stock = stock;
   }
 
-   
   public int getStock() {
     return stock;
   }
@@ -24,6 +22,14 @@ public class PrintedBook extends Book {
 
   @Override
   public String toString() {
-        return "PrintedBook [ISBN=" + isbn + ", Title=" + title + ", Stock=" + stock + ", Available=" + available + "]";
+    return "PrintedBook [ISBN="
+        + isbn
+        + ", Title="
+        + title
+        + ", Stock="
+        + stock
+        + ", Available="
+        + available
+        + "]";
   }
 }

com/study/demo3/StudentManager.java

@@ -1,4 +1,5 @@
 package com.study.demo3;
+
 import java.util.*;
 
 public class StudentManager {

com/study/demo3/Train.java

@@ -1,4 +1,5 @@
 package com.study.demo3;
+
 public class Train extends Vehicle {
   @Override
   public void start() {

com/study/demo3/Vehicle.java

@@ -1,4 +1,5 @@
 package com.study.demo3;
+
 public class Vehicle {
   protected String name;
 

com/study/demo4/AlipayPayment.java

@@ -0,0 +1,9 @@
+package com.study.demo4;
+
+class AlipayPayment implements PaymentProcessor {
+  @Override
+  public boolean pay(double amount) {
+    System.out.println("支付宝支付: " + amount);
+    return true;
+  }
+}

com/study/demo4/BikeDeliveryCalculator.java

@@ -0,0 +1,11 @@
+package com.study.demo4;
+
+class BikeDeliveryCalculator implements DeliveryFeeCalculator {
+  @Override
+  public double calculateFee(double distance) {
+    if (distance <= 5) {
+      return 5.0; // 起步价
+    }
+    return 5.0 + (distance - 5) * 1.5;
+  }
+}

com/study/demo4/Cardeliverycalculator.java

@@ -0,0 +1,12 @@
+package com.study.demo4;
+
+class CarDeliveryCalculator implements DeliveryFeeCalculator {
+  @Override
+  public double calculateFee(double distance) {
+    if (distance <= 5) {
+      return 10.0; // 起步价
+    }
+    return 10.0 + (distance - 5) * 2.0;
+  }
+}
+

com/study/demo4/CreditCardPayment.java

@@ -0,0 +1,9 @@
+package com.study.demo4;
+
+class CreditCardPayment implements PaymentProcessor {
+  @Override
+  public boolean pay(double amount) {
+    System.out.println("银行卡支付: " + amount);
+    return true;
+  }
+}

com/study/demo4/DeliveryFeeCalculator.java

@@ -0,0 +1,5 @@
+package com.study.demo4;
+
+interface DeliveryFeeCalculator {
+  double calculateFee(double distance);
+}

com/study/demo4/HomeAppliance.java

@@ -0,0 +1,26 @@
+package com.study.demo4;
+
+abstract class HomeAppliance implements SmartDevice {
+  protected String name;
+  protected boolean isOn;
+
+  public HomeAppliance(String name) {
+    this.name = name;
+    this.isOn = false;
+  }
+
+  @Override
+  public void turnOn() {
+    isOn = true;
+  }
+
+  @Override
+  public void turnOff() {
+    isOn = false;
+  }
+
+  @Override
+  public String getStatus() {
+    return name + " is " + (isOn ? "ON" : "OFF");
+  }
+}

com/study/demo4/HomeController.java

@@ -0,0 +1,21 @@
+package com.study.demo4;
+
+import java.util.ArrayList;
+import java.util.List;
+
+class HomeController {
+  private List<SmartDevice> devices = new ArrayList<>();
+
+  public void addDevice(SmartDevice device) {
+    devices.add(device);
+  }
+
+  public String getDeviceStatus(String name) {
+    for (SmartDevice device : devices) {
+      if (device.getStatus().contains(name)) {
+        return device.getStatus();
+      }
+    }
+    return "Device not found";
+  }
+}

com/study/demo4/PaymentFactory.java

@@ -0,0 +1,16 @@
+package com.study.demo4;
+
+class PaymentFactory {
+  public static PaymentProcessor getProcessor(String type) {
+    switch (type.toLowerCase()) {
+      case "wechat":
+        return new WechatPayment();
+      case "alipay":
+        return new AlipayPayment();
+      case "card":
+        return new CreditCardPayment();
+      default:
+        throw new IllegalArgumentException("不支持的支付方式");
+    }
+  }
+}

com/study/demo4/PaymentProcessor.java

@@ -0,0 +1,6 @@
+package com.study.demo4;
+
+interface PaymentProcessor {
+  boolean pay(double amount);
+}
+

com/study/demo4/SmartAirConditioner.java

@@ -0,0 +1,7 @@
+package com.study.demo4;
+
+class SmartAirConditioner extends HomeAppliance {
+  public SmartAirConditioner(String name) {
+    super(name);
+  }
+}

com/study/demo4/SmartDevice.java

@@ -0,0 +1,7 @@
+package com.study.demo4;
+
+interface SmartDevice {
+  void turnOn();
+  void turnOff();
+  String getStatus();
+}

com/study/demo4/SmartLight.java

@@ -0,0 +1,7 @@
+package com.study.demo4;
+
+class SmartLight extends HomeAppliance {
+  public SmartLight(String name) {
+    super(name);
+  }
+}

com/study/demo4/SmartMasher.java

@@ -0,0 +1,7 @@
+package com.study.demo4;
+
+class SmartMasher extends HomeAppliance {
+  public SmartMasher(String name) {
+    super(name);
+  }
+}

com/study/demo4/TestControl.java

@@ -0,0 +1,31 @@
+package com.study.demo4;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TestControl {
+  public static void main(String[] args) {
+    HomeController controller = new HomeController();
+
+    // 创建设备
+    SmartLight light = new SmartLight("Living Room Light");
+    SmartAirConditioner ac = new SmartAirConditioner("Bedroom AC");
+    SmartMasher masher = new SmartMasher("Kitchen Masher");
+
+    // 添加到控制器
+    controller.addDevice(light);
+    controller.addDevice(ac);
+    controller.addDevice(masher);
+
+    // 测试设备状态
+    light.turnOff();
+    ac.turnOff();
+    masher.turnOn();
+
+    // 查询状态
+    System.out.println(controller.getDeviceStatus("Living Room Light"));
+    System.out.println(controller.getDeviceStatus("Bedroom AC"));
+    System.out.println(controller.getDeviceStatus("Kitchen Masher"));
+    System.out.println(controller.getDeviceStatus("Non-existent Device"));
+  }
+}

com/study/demo4/TestPay.java

@@ -0,0 +1,8 @@
+package com.study.demo4;
+
+public class TestPay {
+  public static void main(String[] args) {
+    PaymentProcessor processor = PaymentFactory.getProcessor("alipay");
+    processor.pay(666.0);
+  }
+}

com/study/demo4/TestTransport.java

@@ -0,0 +1,22 @@
+package com.study.demo4;
+
+public class TestTransport {
+  public static void main(String[] args) {
+    // 测试自行车配送
+    DeliveryFeeCalculator bike = new BikeDeliveryCalculator();
+    System.out.println("自行车配送 3km: ¥" + bike.calculateFee(3));
+    System.out.println("自行车配送 8km: ¥" + bike.calculateFee(8));
+
+    // 测试汽车配送
+    DeliveryFeeCalculator car = new CarDeliveryCalculator();
+    System.out.println("汽车配送 3km: ¥" + car.calculateFee(3));
+    System.out.println("汽车配送 8km: ¥" + car.calculateFee(8));
+
+    // 对比不同距离的费用
+    System.out.println("\n费用对比:");
+    for (int km = 1; km <= 10; km++) {
+      System.out.printf("%dkm: 自行车¥%.1f, 汽车¥%.1f%n",
+          km, bike.calculateFee(km), car.calculateFee(km));
+    }
+  }
+}

com/study/demo4/WechatPayment.java

@@ -0,0 +1,9 @@
+package com.study.demo4;
+
+class WechatPayment implements PaymentProcessor {
+  @Override
+  public boolean pay(double amount) {
+    System.out.println("微信支付: " + amount);
+    return true;
+  }
+}

com/study/demo5/DataIO.java

@@ -0,0 +1,40 @@
+package com.study.demo5;
+
+import java.io.*;
+
+public class DataIO {
+  public void writeConfig(String path) {
+    try (DataOutputStream dos = new DataOutputStream(
+        new FileOutputStream(path))) {
+
+      dos.writeUTF("李华"); // 用户名
+      dos.writeInt(25); // 年龄
+      dos.writeBoolean(true); // 是否启用
+      dos.writeDouble(1234.56); // 余额
+
+      System.out.println("配置写入成功: " + path);
+
+    } catch (IOException e) {
+      System.err.println("写入配置失败: " + e.getMessage());
+    }
+  }
+
+  public void readConfig(String path) {
+    try (DataInputStream dis = new DataInputStream(
+        new FileInputStream(path))) {
+
+      String username = dis.readUTF();
+      int age = dis.readInt();
+      boolean enabled = dis.readBoolean();
+      double balance = dis.readDouble();
+
+      System.out.println("用户名: " + username);
+      System.out.println("年龄: " + age);
+      System.out.println("是否启用: " + enabled);
+      System.out.println("余额: " + balance);
+
+    } catch (IOException e) {
+      System.err.println("读取配置失败: " + e.getMessage());
+    }
+  }
+}

com/study/demo5/FileCopy.java

@@ -0,0 +1,20 @@
+package com.study.demo5;
+
+import java.io.*;
+
+public class FileCopy {
+  public void copy(String source, String target) {
+    try (FileInputStream fis = new FileInputStream(source);
+        FileOutputStream fos = new FileOutputStream(target)) {
+      byte[] buffer = new byte[1024];
+      int bytesRead;
+      while ((bytesRead = fis.read(buffer)) != -1) {
+        fos.write(buffer, 0, bytesRead);
+      }
+    } catch (FileNotFoundException e) {
+      System.err.println("源文件未找到: " + e.getMessage());
+    } catch (IOException e) {
+      System.err.println("文件复制失败: " + e.getMessage());
+    }
+  }
+}

com/study/demo5/FileStat.java

@@ -0,0 +1,25 @@
+package com.study.demo5;
+
+import java.io.*;
+
+public class FileStat {
+  public long countBytes(String filePath) {
+    long totalBytes = 0;
+
+    try (FileInputStream fis = new FileInputStream(filePath)) {
+
+      byte[] buffer = new byte[1024];
+      int bytesRead;
+
+      while ((bytesRead = fis.read(buffer)) != -1) {
+        totalBytes += bytesRead;
+      }
+
+    } catch (IOException e) {
+      System.err.println("文件读取失败: " + e.getMessage());
+      return -1;
+    }
+
+    return totalBytes;
+  }
+}

com/study/demo5/Main.java

@@ -0,0 +1,17 @@
+package com.study.demo5;
+
+ public class Main {
+    public static void main(String[] args) {
+        // 7.1 测试
+        FileCopy fc = new FileCopy();
+        fc.copy("source.txt", "target.txt");
+        // 7.2 测试
+        DataIO dataIO = new DataIO();
+        dataIO.writeConfig("config.bin");
+        dataIO.readConfig("config.bin");
+        // 7.3 测试
+        FileStat fs = new FileStat();
+        long size = fs.countBytes("test3.txt");
+        System.out.println("文件大小: " + size + " 字节");
+    }
+}

com/study/demo6/SumThread.java

@@ -0,0 +1,52 @@
+package com.study.demo6;
+
+public class SumThread {
+  static class PartSumTask implements Runnable {
+    private final int[] array;
+    private final int start;
+    private final int end;
+    public long result;
+
+    public PartSumTask(int[] array, int start, int end) {
+      this.array = array;
+      this.start = start;
+      this.end = end;
+    }
+
+    @Override
+    public void run() {
+      long sum = 0;
+      for (int i = start; i <= end; i++) {
+        sum += array[i];
+      }
+      result = sum;
+    }
+  }
+
+  public static void main(String[] args) throws InterruptedException {
+    int size = 1_000_000;
+    int[] array = new int[size];
+    for (int i = 0; i < size; i++) {
+      array[i] = i;
+    }
+
+    PartSumTask task1 = new PartSumTask(array, 0, 333_333);
+    PartSumTask task2 = new PartSumTask(array, 333_334, 666_666);
+    PartSumTask task3 = new PartSumTask(array, 666_667, 999_999);
+
+    Thread t1 = new Thread(task1);
+    Thread t2 = new Thread(task2);
+    Thread t3 = new Thread(task3);
+
+    t1.start();
+    t2.start();
+    t3.start();
+
+    t1.join();
+    t2.join();
+    t3.join();
+
+    long total = task1.result + task2.result + task3.result;
+    System.out.println("总和为：" + total);
+  }
+}

com/study/demo6/ThreadDemo1.java

@@ -0,0 +1,20 @@
+package com.study.demo6;
+
+public class ThreadDemo1 {
+  static class MyThread extends Thread {
+    @Override
+    public void run() {
+      for (int i = 1; i <= 5; i++) {
+        System.out.println("当前线程：" + getName() + "，输出次数 " + i);
+      }
+    }
+  }
+
+  public static void main(String[] args) {
+    MyThread s1 = new MyThread();
+    MyThread s2 = new MyThread();
+
+    s1.start();
+    s2.start();
+  }
+}

com/study/demo6/ThreadDemo2.java

@@ -0,0 +1,22 @@
+package com.study.demo6;
+
+public class ThreadDemo2 {
+  static class CountTask implements Runnable {
+    @Override
+    public void run() {
+      for (int i = 1; i <= 10; i++) {
+        System.out.println(Thread.currentThread().getName() + " 计数：" + i);
+        try {
+          Thread.sleep(500);
+        } catch (InterruptedException e) {
+          e.printStackTrace();
+        }
+      }
+    }
+  }
+
+  public static void main(String[] args) {
+    Thread t = new Thread(new CountTask(), "计数线程");
+    t.start();
+  }
+}

flake.nix

@@ -3,7 +3,7 @@
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
   outputs = { self, nixpkgs }:
   let
-    supportedSystems = [ "x86_64-linux" "aarch64-linux" ];
+    supportedSystems = [ "x86_64-linux" ];
     forEachSupportedSystem = f: nixpkgs.lib.genAttrs supportedSystems (system: f {
       pkgs = import nixpkgs { inherit self system; };
     });