10.NIO之Files Demo

Leefs 2022-05-30 PM 752℃ 0条

[TOC]

### 一、遍历目录文件

```java
import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author lilinchao
 * @date 2022/5/30
 * @description 遍历目录，统计文件和文件夹个数
 **/
public class FilesTraverseDirectoryDemo {
    public static void main(String[] args) throws IOException {
        Path path = Paths.get("D:\\Tools\\jdk1.8.0_201");
        AtomicInteger dirCount = new AtomicInteger();
        AtomicInteger fileCount = new AtomicInteger();

Files.walkFileTree(path,new SimpleFileVisitor<Path>(){
            //preVisitDirectory()在访问任何目录前被调用
            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
                System.out.println(dir);
                dirCount.incrementAndGet();
                return super.preVisitDirectory(dir, attrs);
            }

//visitFile()在访问任何文件时被调用
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                System.out.println(file);
                fileCount.incrementAndGet();
                return super.visitFile(file, attrs);
            }
        });
        System.out.println(dirCount);
        System.out.println(fileCount);
    }
}
```

### 二、统计Jar的数目

```java
import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author lilinchao
 * @date 2022/5/30
 * @description 统计文件中Jar的个数
 **/
public class FilesCountJarNumberDemo {
    public static void main(String[] args) throws IOException {
        Path path = Paths.get("D:\\Tools\\jdk1.8.0_201");
        AtomicInteger fileCount = new AtomicInteger();

Files.walkFileTree(path,new SimpleFileVisitor<Path>(){
            //visitFile()在访问任何文件时被调用
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                if(file.toFile().getName().endsWith(".jar")){
                    fileCount.incrementAndGet();
                }
                return super.visitFile(file, attrs);
            }
        });
        System.out.println(fileCount);
    }
}
```

### 三、删除多级目录

```java
import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;

/**
 * @author lilinchao
 * @date 2022/5/30
 * @description 删除多级目录
 **/
public class FilesDeleteDirectoryDemo {
    public static void main(String[] args) throws IOException {
        Path path = Paths.get("D:\\libs2");

//postVisitDirectory()在访问任何目录后被调用
            @Override
            public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
                Files.delete(dir);
                return super.postVisitDirectory(dir, exc);
            }
        });
        System.out.println("删除完毕!");
    }
}
```

### 四、拷贝多级目录

```java
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

/**
 * @author lilinchao
 * @date 2022/5/30
 * @description 拷贝多级目录
 **/
public class FilesCopyDirectoryDemo {
    public static void main(String[] args) throws IOException {
        long start = System.currentTimeMillis();
        String source = "D:\\libs";
        String target = "D:\\libs_aaa";

Files.walk(Paths.get(source)).forEach(path -> {
            try {
                String targetName = path.toString().replace(source,target);
                //是目录
                if(Files.isDirectory(path)){
                    //createDirectory()方法利用Path创建一个新的目录
                    Files.createDirectory(Paths.get(targetName));
                }else if(Files.isRegularFile(path)){ //是普通文件
                    //copy()方法将文件从一个path复制到另一个
                    Files.copy(path,Paths.get(targetName));
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
        long end = System.currentTimeMillis();
        System.out.println(end - start);
    }
}
```

标签: Netty, NIO

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