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The FileUtil class provides comprehensive utilities for file operations including reading, writing, extracting from JAR files, and various file manipulation tasks.

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Getting files

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Create or get files

// Get file from plugin folder (creates if doesn't exist)
File file = FileUtil.getOrMakeFile("config.yml");

// Just get file (may not exist)
File file = FileUtil.getFile("data/players.yml");

// Create file if it doesn't exist
File file = FileUtil.createIfNotExists("logs/server.log");

​
Get multiple files

// Get all .yml files in directory
File[] configs = FileUtil.getFiles("configs", "yml");

// Get all .txt files
File[] texts = FileUtil.getFiles("data", ".txt");

for (File file : configs) {
    Common.log("Found: " + file.getName());
}

​
File name extraction

// Get file name without extension
String name = FileUtil.getFileName("classes/Warrior.yml");
// Result: "Warrior"

String name = FileUtil.getFileName(new File("config.yml"));
// Result: "config"

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Reading files

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Read lines

// Read all lines from file
List<String> lines = FileUtil.readLines("config.yml");

// Read from File object
File file = new File("data.txt");
List<String> lines = FileUtil.readLines(file);

// Process lines
for (String line : lines) {
    Common.log(line);
}

​
Read from URL

// Read from URL
try {
    URL url = new URL("https://example.com/data.txt");
    List<String> lines = FileUtil.readLines(url);
    
    for (String line : lines) {
        Common.log(line);
    }
} catch (IOException ex) {
    Common.error(ex, "Failed to read from URL");
}

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Writing files

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Simple writing

// Write lines to file (appends)
FileUtil.write("logs/server.log", 
    "Server started",
    "Players online: 5"
);

// Write collection
List<String> data = Arrays.asList("Line 1", "Line 2");
FileUtil.write("data.txt", data);

// Write to File object
File file = new File("output.txt");
FileUtil.write(file, "Content here");

​
Formatted writing

// Write with timestamp and optional prefix
FileUtil.writeFormatted("logs/errors.log", "Error occurred!");
// Result: [2024-01-15 14:30:45] Error occurred!

// Write with custom prefix
FileUtil.writeFormatted("logs/admin.log", "ADMIN", "Player banned");
// Result: [2024-01-15 14:30:45] ADMIN: Player banned

​
Advanced writing

import java.nio.file.StandardOpenOption;

// Truncate file before writing
FileUtil.write(file, data, StandardOpenOption.TRUNCATE_EXISTING);

// Append to file
FileUtil.write(file, data, StandardOpenOption.APPEND);

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Extracting from JAR

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Extract files

// Extract file from plugin JAR
File extracted = FileUtil.extract("config.yml");

// Extract to different location
File extracted = FileUtil.extract(
    "defaults/config.yml",
    "config.yml"
);
Extracted files support variable replacement:
  • {plugin_name} - Plugin name
  • {plugin_name_lower} - Lowercase plugin name
  • {file} - File name

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Extract raw files

// Extract binary files (images, etc.)
File image = FileUtil.extractRaw("icon.png");

​
Extract folders

// Extract entire folder from JAR
FileUtil.extractFolderFromJar(
    "languages/",
    "languages"
);

​
Get internal file content

// Read file content from JAR without extracting
List<String> lines = FileUtil.getInternalFileContent("config.yml");

if (lines != null) {
    for (String line : lines) {
        Common.log(line);
    }
}

​
File operations

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Delete recursively

// Delete file/folder and all contents
File folder = new File("old_data");
FileUtil.deleteRecursivelly(folder);

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Create ZIP archive

// Create ZIP from directory
try {
    FileUtil.zip(
        "world",        // Source directory
        "backups/world" // Destination (no .zip extension)
    );
    
    Common.log("Backup created!");
} catch (IOException ex) {
    Common.error(ex, "Failed to create backup");
}

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Examples

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Configuration backup system

public class ConfigBackup {
    
    public void backupConfigs() {
        try {
            // Create backup folder
            String timestamp = TimeUtil.getFormattedDate()
                .replace(" ", "_")
                .replace(":", "-");
            
            String backupPath = "backups/config_" + timestamp;
            
            // Copy all config files
            File[] configs = FileUtil.getFiles("", "yml");
            
            for (File config : configs) {
                List<String> lines = FileUtil.readLines(config);
                FileUtil.write(
                    backupPath + "/" + config.getName(),
                    lines
                );
            }
            
            // Create ZIP
            FileUtil.zip(backupPath, backupPath);
            
            // Delete folder (keep only ZIP)
            FileUtil.deleteRecursivelly(new File(backupPath));
            
            Common.log("Backup created: " + backupPath + ".zip");
            
        } catch (Exception ex) {
            Common.error(ex, "Failed to backup configs");
        }
    }
}

​
Player data manager

public class PlayerDataManager {
    
    private final String DATA_FOLDER = "playerdata";
    
    public void savePlayerData(UUID uuid, List<String> data) {
        String path = DATA_FOLDER + "/" + uuid + ".txt";
        FileUtil.write(path, data);
    }
    
    public List<String> loadPlayerData(UUID uuid) {
        String path = DATA_FOLDER + "/" + uuid + ".txt";
        File file = FileUtil.getFile(path);
        
        if (file.exists()) {
            return FileUtil.readLines(file);
        }
        
        return new ArrayList<>();
    }
    
    public void deletePlayerData(UUID uuid) {
        String path = DATA_FOLDER + "/" + uuid + ".txt";
        File file = FileUtil.getFile(path);
        
        if (file.exists()) {
            file.delete();
        }
    }
}

​
Log rotation system

public class LogManager {
    
    private static final int MAX_LOG_SIZE = 1024 * 1024; // 1MB
    
    public void log(String message) {
        File logFile = FileUtil.getOrMakeFile("logs/latest.log");
        
        // Check if rotation needed
        if (logFile.length() > MAX_LOG_SIZE) {
            rotateLog(logFile);
        }
        
        // Write to log
        FileUtil.writeFormatted("logs/latest.log", "LOG", message);
    }
    
    private void rotateLog(File currentLog) {
        try {
            // Read current log
            List<String> lines = FileUtil.readLines(currentLog);
            
            // Save to dated file
            String timestamp = TimeUtil.getFormattedDate()
                .replace(" ", "_")
                .replace(":", "-");
            
            FileUtil.write(
                "logs/" + timestamp + ".log",
                lines
            );
            
            // Clear current log
            currentLog.delete();
            FileUtil.createIfNotExists("logs/latest.log");
            
        } catch (Exception ex) {
            Common.error(ex, "Failed to rotate log");
        }
    }
}

​
Language file loader

public class LanguageLoader {
    
    public void loadLanguages() {
        // Extract default languages if not exist
        if (!FileUtil.getFile("languages").exists()) {
            FileUtil.extractFolderFromJar("languages/", "languages");
        }
        
        // Load all language files
        File[] langFiles = FileUtil.getFiles("languages", "yml");
        
        for (File langFile : langFiles) {
            String locale = FileUtil.getFileName(langFile);
            List<String> lines = FileUtil.readLines(langFile);
            
            Common.log("Loaded language: " + locale + 
                      " (" + lines.size() + " lines)");
        }
    }
}

​
Update checker

public class UpdateChecker {
    
    public void checkForUpdates(String versionUrl) {
        try {
            URL url = new URL(versionUrl);
            List<String> lines = FileUtil.readLines(url);
            
            if (!lines.isEmpty()) {
                String latestVersion = lines.get(0);
                String currentVersion = SimplePlugin.getVersion();
                
                if (!latestVersion.equals(currentVersion)) {
                    Common.log(
                        "&eNew version available: " + latestVersion,
                        "&eCurrent version: " + currentVersion
                    );
                }
            }
            
        } catch (Exception ex) {
            Common.log("Could not check for updates");
        }
    }
}
Use FileUtil.writeFormatted() for log files to automatically include timestamps.

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