随机选择文件，向后写入文件内容

文章目录 一、 需求概述二、Java实现1、添加依赖2、源码实现 三、运行结果

一、 需求概述

指定文件目录，搜索某类型文本文件，随机选择几个做内容交换。

思路：

将原始数据看做内齿轮，复制的内容数据看做外齿轮，将外部齿轮顺时针挪一步后写入，便实现了数据的腾挪！

二、Java实现 1、添加依赖

pom.xml

<dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-simple</artifactId> <version>2.0.16</version> </dependency> <dependency> <groupId>org.apache mons</groupId> <artifactId>commons-lang3</artifactId> <version>3.5</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.15.0</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.12</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter-engine</artifactId> <version>5.5.2</version> </dependency> 2、源码实现 import java.io.File; import java.io.IOException; import java.nio.charset.StandardCharsets; import java.util.List; import java.util.Objects; import java.util.Random; import java.util.concurrent.atomic.AtomicInteger; import java.util.stream.Collectors; import java.util.stream.IntStream; import org.apache mons.io.FileUtils; import org.apache mons.lang3.StringUtils; import org.junit.jupiter.api.BeforeAll; import org.junit.jupiter.api.Test; import lombok.extern.slf4j.Slf4j; /** * 随机选择文件，向后写入文件内容 */ @Slf4j public class FileExchange { static String path = System.getenv().get("USERPROFILE") + "\\Pictures\\"; File directory = new File(path); /** * 创建测试文件 */ @BeforeAll public static void init() { IntStream.rangeClosed(0, 10).forEach(i -> { try { File file = new File(path + i + ".txt"); FileUtils.writeStringToFile(file, Objects.toString(i), StandardCharsets.UTF_8); } catch (IOException e) { log.error(e.getMessage(), e); } }); } @Test public void test() { List<File> files = FileUtils.listFiles(directory, new String[] {"txt"}, true).stream().collect(Collectors.toList()); // 随机选择多个 List<File> chooseFiles = new Random().ints(5, 0, files.size()) .mapToObj(index -> files.get(index)) .distinct() .peek(f -> log.info("{}", f.getAbsolutePath())) // 打印 .collect(Collectors.toList()); int length = chooseFiles.size(); if (length > 1) { List<String> texts = chooseFiles.stream().map(file -> readText(file)).collect(Collectors.toList()); if (texts.stream().allMatch(text -> StringUtils.isNotBlank(text))) { AtomicInteger index = new AtomicInteger(); texts.forEach(text -> { try { File dest = chooseFiles.get(index.incrementAndGet() % length); FileUtils.writeStringToFile(dest, text, StandardCharsets.UTF_8); log.info("{} ===> {}", text, dest.getAbsolutePath()); } catch (IOException e) { log.error(e.getMessage(), e); } }); } } } /** * 读取文件文本内容 * * @param file * @return */ private String readText(File file) { try { return FileUtils.readFileToString(file, StandardCharsets.UTF_8); } catch (IOException e) { log.error(e.getMessage(), e); return null; } } } 三、运行结果 2025-03-04 18:44:56.204 INFO 27280 --- [main] c.f.f.FileExchange : C:\Users\DELL\Pictures\6.txt 2025-03-04 18:44:56.206 INFO 27280 --- [main] c.f.f.FileExchange : C:\Users\DELL\Pictures\3.txt 2025-03-04 18:44:56.206 INFO 27280 --- [main] c.f.f.FileExchange : C:\Users\DELL\Pictures\8.txt 2025-03-04 18:44:56.206 INFO 27280 --- [main] c.f.f.FileExchange : C:\Users\DELL\Pictures\9.txt 2025-03-04 18:44:56.206 INFO 27280 --- [main] c.f.f.FileExchange : C:\Users\DELL\Pictures\5.txt 2025-03-04 18:44:56.213 INFO 27280 --- [main] c.f.f.FileExchange : 6 ===> C:\Users\DELL\Pictures\3.txt 2025-03-04 18:44:56.214 INFO 27280 --- [main] c.f.f.FileExchange : 3 ===> C:\Users\DELL\Pictures\8.txt 2025-03-04 18:44:56.214 INFO 27280 --- [main] c.f.f.FileExchange : 8 ===> C:\Users\DELL\Pictures\9.txt 2025-03-04 18:44:56.215 INFO 27280 --- [main] c.f.f.FileExchange : 9 ===> C:\Users\DELL\Pictures\5.txt 2025-03-04 18:44:56.215 INFO 27280 --- [main] c.f.f.FileExchange : 5 ===> C:\Users\DELL\Pictures\6.txt