Java文件操作相关

1. 文件上传

import java.io.File;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
 
public class FileUpload {
    public static void main(String[] args) {
        File source = new File("/path/to/source/file");
        File dest = new File("/path/to/destination/file");
 
        try {
            FileUtils.copyFile(source, dest);
            System.out.println("File uploaded successfully!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2. 文件下载

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
 
public class FileDownload {
    public static void main(String[] args) {
        String url = "https://example.com/file-to-download.txt";
        String fileName = "file-to-download.txt";
 
        try {
            URL website = new URL(url);
            ReadableByteChannel rbc = Channels.newChannel(website.openStream());
            FileOutputStream fos = new FileOutputStream(fileName);
            fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
            fos.close();
            rbc.close();
            System.out.println("File downloaded successfully!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

3. 文件压缩

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
 
public class FileCompression {
    public static void main(String[] args) {
        File source = new File("/path/to/source/file");
        File dest = new File("/path/to/destination/file.zip");
 
        try {
            FileOutputStream fos = new FileOutputStream(dest);
            ZipOutputStream zos = new ZipOutputStream(fos);
            byte[] buffer = new byte[1024];
            FileInputStream fis = new FileInputStream(source);
            zos.putNextEntry(new ZipEntry(source.getName()));
            int length;
            while ((length = fis.read(buffer)) > 0) {
                zos.write(buffer, 0, length);
            }
            zos.closeEntry();
            fis.close();
            zos.close();
            System.out.println("File compressed successfully!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4. 文件转PDF

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
 
public class FileToPdf {
    public static void main(String[] args) {
        File source = new File("/path/to/source/file");
        File dest = new File("/path/to/destination/file.pdf");
 
        try {
            Document document = new Document();
            PdfWriter.getInstance(document, new FileOutputStream(dest));
            document.open();
            FileInputStream fis = new FileInputStream(source);
            byte[] buffer = new byte[1024];
            int length;
            while ((length = fis.read(buffer)) > 0) {
                document.add(new com.itextpdf.text.Paragraph(new String(buffer, 0, length)));
            }
            document.close();
            fis.close();
            System.out.println("File converted to PDF successfully!");
        } catch (IOException | DocumentException e) {
            e.printStackTrace();
        }
    }
}

Q.E.D.