Java服务中的大文件上传和下载优化技巧分享

import org.springframework.web.multipart.MultipartFile;
import java.io.RandomAccessFile;
import java.io.File;
import java.io.IOException;
public void uploadFile(MultipartFile file, int chunk, int chunks) throws IOException {
    File destFile = new File("file/" + file.getOriginalFilename());
    if(chunk == 0 && !destFile.exists()) {
        destFile.createNewFile();
    }
    RandomAccessFile raf = new RandomAccessFile(destFile, "rw");
    raf.seek(chunk * CHUNK_SIZE);
    raf.write(file.getBytes());
    raf.close();
    if(chunk == chunks - 1) {
        // All chunks are uploaded, you can now merge or process them as needed
    }
}

import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;
public void multiThreadUploadFile(File file) {
    ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(5);
    long chunkSize = file.length() / 5;  
    for (int i = 0; i < 5; i++) {
        long start = i * chunkSize;
        long end = (i == 4) ? file.length() : start + chunkSize;  
        executor.submit(new FileUploadTask(file, start, end)); // Assume FileUploadTask is your defined task that handles file upload
    }
}

import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.net.URL;
public void streamDownloadFile(String fileURL, Path filePath) throws IOException {
    try (InputStream in = new URL(fileURL).openStream()) {
        Files.copy(in, filePath, StandardCopyOption.REPLACE_EXISTING);
    }
}

import java.nio.channels.FileChannel;
import java.io.RandomAccessFile;
import java.io.File;
public void nioFileCopy(File source, File dest) throws IOException {
    try (FileChannel sourceChannel = new RandomAccessFile(source, "r").getChannel();
         FileChannel destChannel = new RandomAccessFile(dest, "rw").getChannel()) {
        long position = 0;
        long count = sourceChannel.size();
        while (position < count) {
            position += sourceChannel.transferTo(position, 1024L * 1024L, destChannel);
        }
    }
}

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import java.util.Properties;
public void sendMessage(String topic, String message) {
    Properties properties = new Properties();
    properties.put("bootstrap.servers", "localhost:9092");
    properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
    properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
    KafkaProducer<String, String> producer = new KafkaProducer<>(properties);
    producer.send(new ProducerRecord<>(topic, message));
    producer.close();
}