feat(新增): 🚀 学习文件和文件夹操作，遍历，查找，复制，删除

.idea/jarRepositories.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://repo.maven.apache.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+  </component>
+</project>

.idea/misc.xml

@@ -8,7 +8,7 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_X" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>

data.txt

@@ -0,0 +1 @@
+helloworld你好

demo1/src/main/java/cn/bunny/Demo10.java

@@ -0,0 +1,77 @@
+package cn.bunny;
+
+import java.io.IOException;
+import java.nio.file.*;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class Demo10 {
+    public static void main(String[] args) throws IOException {
+        AtomicInteger atomicInteger = new AtomicInteger();
+        m1();
+        Files.walkFileTree(Paths.get("D:\\BaiduNetdiskDownload\\web项目\\大屏模板"), new SimpleFileVisitor<>(){
+            /**
+             * Invoked for a file in a directory.
+             *
+             * <p> Unless overridden, this method returns {@link FileVisitResult#CONTINUE
+             * CONTINUE}.
+             *
+             * @param file
+             * @param attrs
+             */
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                if (file.endsWith(".jpg")) {
+                    System.out.println(file);
+                    atomicInteger.incrementAndGet();
+                }
+                return super.visitFile(file, attrs);
+            }
+        });
+
+        System.out.println("===>" + atomicInteger);
+    }
+
+    private static void m1() throws IOException {
+        AtomicInteger dirCount = new AtomicInteger();
+        AtomicInteger fileCount = new AtomicInteger();
+
+        // 访问者模式
+        Files.walkFileTree(Paths.get("D:\\BaiduNetdiskDownload\\web项目\\大屏模板"), new SimpleFileVisitor<>() {
+            /**
+             * Invoked for a directory before entries in the directory are visited.
+             *
+             * <p> Unless overridden, this method returns {@link FileVisitResult#CONTINUE
+             * CONTINUE}.
+             *
+             * @param dir
+             * @param attrs
+             */
+            @Override
+            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
+                System.out.println("===>"+dir);
+                dirCount.incrementAndGet();
+                return super.preVisitDirectory(dir, attrs);
+            }
+
+            /**
+             * Invoked for a file in a directory.
+             *
+             * <p> Unless overridden, this method returns {@link FileVisitResult#CONTINUE
+             * CONTINUE}.
+             *
+             * @param file
+             * @param attrs
+             */
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                System.out.println("===>"+file);
+                fileCount.decrementAndGet();
+                return super.visitFile(file, attrs);
+            }
+        });
+
+        System.out.println("文件夹的===>" + dirCount);
+        System.out.println("文件的===>" + fileCount);
+    }
+}

demo1/src/main/java/cn/bunny/Demo3.java

@@ -1,6 +1,5 @@
 package cn.bunny;
 
-
 import java.nio.ByteBuffer;
 
 public class Demo3 {
@@ -10,6 +9,7 @@ public class Demo3 {
         buffer.put((byte) 0x61);
         buffer.put(new byte[]{0x62, 0x63, 0x64});
 
+        // 共有4个值
         System.out.println(buffer);
     }
 }

demo1/src/main/java/cn/bunny/Demo4.java

@@ -3,6 +3,7 @@ package cn.bunny;
 import java.nio.ByteBuffer;
 
 public class Demo4 {
+
     public static void main(String[] args) {
         ByteBuffer buffer = ByteBuffer.allocate(10);
         buffer.put(new byte[]{'a', 'b', 'c', 'd', 'e'});
@@ -16,5 +17,8 @@ public class Demo4 {
         // mark & reset
         System.out.println((char) buffer.get());// b
         System.out.println((char) buffer.get());// c
+
+        // get(i) 不会改变读索引
+        System.out.println((char) buffer.get());
     }
 }

demo1/src/main/java/cn/bunny/Demo5.java

@@ -0,0 +1,26 @@
+package cn.bunny;
+
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+
+public class Demo5 {
+
+    public static void main(String[] args) {
+        // 将字符串转成ByteBuffer
+        ByteBuffer buffer = ByteBuffer.allocate(16);
+        buffer.put("hello".getBytes());
+
+        // 转换方式二
+        ByteBuffer buffer1 = StandardCharsets.UTF_8.encode("hello");
+        System.out.println(buffer1);
+
+        // 转换方式三
+        ByteBuffer buffer2 = ByteBuffer.wrap("hello".getBytes());
+        System.out.println(buffer2);
+
+        // 使用读模式才能有值
+        buffer1.flip();
+        String str1 = StandardCharsets.UTF_8.decode(buffer1).toString();
+        System.out.println(str1);
+    }
+}

demo1/src/main/java/cn/bunny/Demo6.java

@@ -0,0 +1,23 @@
+package cn.bunny;
+
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.StandardCharsets;
+
+public class Demo6 {
+
+    public static void main(String[] args) {
+        ByteBuffer b1Buffer = StandardCharsets.UTF_8.encode("hello");
+        ByteBuffer b2Buffer = StandardCharsets.UTF_8.encode("world");
+        ByteBuffer b3Buffer = StandardCharsets.UTF_8.encode("你好");
+
+        try (FileChannel channel = new RandomAccessFile("data.txt", "rw").getChannel()) {
+            channel.write(new ByteBuffer[]{b1Buffer, b2Buffer, b3Buffer});
+
+        } catch (IOException exception) {
+
+        }
+    }
+}

demo1/src/main/java/cn/bunny/Demo7.java

@@ -0,0 +1,31 @@
+package cn.bunny;
+
+import java.nio.ByteBuffer;
+
+public class Demo7 {
+
+    public static void main(String[] args) {
+        // 黏包 和 半包
+        // 黏包：很多字符串连在一起
+        // 半包：有部分没有发送完成
+        ByteBuffer buffer = ByteBuffer.allocate(32);
+        buffer.put("Hello World!\nI'm running\nHo".getBytes());
+        split(buffer);
+        buffer.put("w are you!".getBytes());
+        // split(buffer);
+    }
+
+    private static void split(ByteBuffer buffer) {
+        buffer.flip();
+        for (int i = 0; i < buffer.limit(); i++) {
+            if (buffer.get(i) == '\n') {
+                int len = i + 1 - buffer.position();
+                ByteBuffer target = ByteBuffer.allocate(len);
+                for (int j = 0; j < len; j++) {
+                    // byte b = buffer.get();
+                    target.put(buffer.get());
+                }
+            }
+        }
+    }
+}

demo1/src/main/java/cn/bunny/Demo8.java

@@ -0,0 +1,25 @@
+package cn.bunny;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.nio.channels.FileChannel;
+
+public class Demo8 {
+    public static void main(String[] args) {
+        // 只能传输 2g
+        try (
+                FileChannel fileChannel = new FileInputStream("data.txt").getChannel();
+                FileChannel channel = new FileOutputStream("to.txt").getChannel();
+        ) {
+            // 针对只能传输两个G做了以下优化
+            long size = fileChannel.size();
+            // 分多次传输两个G内容
+            for (long left = size; left > 0; ) {
+                left -= fileChannel.transferTo((size - left), left, channel);
+            }
+            // fileChannel.transferTo(0, fileChannel.size(), channel);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}

demo1/src/main/java/cn/bunny/Demo9.java

@@ -0,0 +1,37 @@
+package cn.bunny;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+
+public class Demo9 {
+    public static void main(String[] args) throws IOException {
+        Path path = Paths.get("D:\\BaiduNetdiskDownload\\java项目\\目录");
+        // 正常化路径
+        System.out.println(path.normalize());
+
+        // 判断文件是否存在
+        System.out.println(Files.exists(path));
+
+        // 创建单层目录
+        Files.createDirectory(path);
+
+        // 创建多层目录
+        Files.createDirectories(path);
+
+        // 拷贝文件
+        Path source = Paths.get("data.txt");
+        Path target = Paths.get("target.txt");
+        Files.copy(source, target);
+        // 如果存在文件覆盖文件
+        Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);
+        // 拷贝保证文件原子性
+        Files.copy(source, target, StandardCopyOption.ATOMIC_MOVE);
+
+        // 删除文件，只能删除空目录，如果有内容无法删除
+        Files.delete(path);
+    }
+}

demo1/target/maven-status/maven-compiler-plugin/compile/default-compile/createdFiles.lst

@@ -0,0 +1,3 @@
+cn\bunny\Demo5.class
+cn\bunny\Demo7.class
+cn\bunny\Demo6.class

demo1/target/maven-status/maven-compiler-plugin/compile/default-compile/inputFiles.lst

@@ -1,5 +1,7 @@
-D:\MyFolder\Netty\bytebuffter\demo1\src\main\java\cn\bunny\ByteBufferUtil.java
-D:\MyFolder\Netty\bytebuffter\demo1\src\main\java\cn\bunny\Demo01.java
-D:\MyFolder\Netty\bytebuffter\demo1\src\main\java\cn\bunny\Demo3.java
-D:\MyFolder\Netty\bytebuffter\demo1\src\main\java\cn\bunny\Demo02.java
-D:\MyFolder\Netty\bytebuffter\demo1\src\main\java\cn\bunny\Main.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo3.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo01.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo02.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo4.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo7.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo5.java
+D:\BaiduNetdiskDownload\java项目\netty\demo1\src\main\java\cn\bunny\Demo6.java

to.txt

@@ -0,0 +1 @@
+helloworld你好