文件下载功能

最新推荐文章于 2024-02-27 16:03:12 发布

原创最新推荐文章于 2024-02-27 16:03:12 发布 · 341 阅读

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本文介绍了一个用于从HTTPS源下载文件的Java工具类。该工具通过指定URL路径和下载目录来实现文件的下载，并包含了错误处理机制确保下载过程的稳定性和安全性。

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import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class HttpsConnectionUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(HttpsConnectionUtil.class);

    private HttpsConnectionUtil() {

    }

    public static File downloadFile(String urlPath, String downloadDir) {
        HttpURLConnection httpURLConnection = null;
        try {
            URL url = new URL(urlPath);
            httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestProperty("Charset", "UTF-8");
            httpURLConnection.connect();
        } catch (MalformedURLException e) {
            LOGGER.error("Get MalformedURLException.", e);
        } catch (IOException e) {
            LOGGER.error("Get IOException.", e);
        }

        File file = null;
        if (null == httpURLConnection) {
            return file;
        }

        int responseCode = 404;
        try {
            responseCode = httpURLConnection.getResponseCode();
        } catch (IOException e) {
            LOGGER.error("Get response code error.", e);
            return file;
        }

        if (responseCode == HttpURLConnection.HTTP_OK) {
            OutputStream out = null;
            try (BufferedInputStream bin = new BufferedInputStream(httpURLConnection.getInputStream())) {
                // 文件名
                String filePathUrl = httpURLConnection.getURL().getFile();
                String fileFullName = filePathUrl.substring(filePathUrl.lastIndexOf('/') + 1);

                String path = downloadDir + '/' + fileFullName;
                file = new File(path);
                if (!file.getParentFile().exists()) {
                    file.getParentFile().mkdirs();
                }

                int size = 0;
                byte[] buff = new byte[1024];

                out = new FileOutputStream(file);
                while ((size = bin.read(buff)) != -1) {
                    out.write(buff, 0, size);
                }
            } catch (IOException e) {
                LOGGER.info("Download file error.", e);
            } finally {
                try {
                    if (null != out) {
                        out.close();
                    }
                } catch (IOException e) {
                    LOGGER.error("Close I/O error.", e);
                }
            }
        } else {
            LOGGER.info("Download file: {} failed, responseCode:{}.", urlPath, responseCode);
        }
        return file;
    }

}