java 从fileNet中高效下载文件

在Java中，从FileNet高效地下载文件通常涉及使用FTP (File Transfer Protocol) 或HTTP(S)库，如Apache Commons Net或Java内置的URLConnection。以下是基本步骤：

1. 导入所需的库：

import org.apache.commons.net.ftp.FTPClient;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;

2. 对于FTP：

FTPClient ftp = new FTPClient();
try {
    // 连接到FTP服务器
    ftp.connect("ftp.example.com", 21);
    ftp.login("username", "password");
    
    // 选择目录
    ftp.changeWorkingDirectory("/path/to/download/folder");

    // 打开并下载文件
    InputStream fis = ftp.retrieveFileStream("filename.zip");
    FileOutputStream fos = new FileOutputStream("local_file_path.zip");
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = fis.read(buffer)) != -1) {
        fos.write(buffer, 0, bytesRead);
    }
    fos.close();
    fis.close();

    // 关闭连接
    ftp.logout();
    ftp.disconnect();
} catch (Exception e) {
    e.printStackTrace();
}

3. 对于HTTP(S)：

URL url = new URL("https://example.com/file.zip");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
try {
    connection.setRequestMethod("GET");
    connection.connect();

    // 获取输入流
    InputStream in = connection.getInputStream();
    FileOutputStream fos = new FileOutputStream("local_file_path.zip");
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = in.read(buffer)) != -1) {
        fos.write(buffer, 0, bytesRead);
    }
    fos.close();
    in.close();

    connection.disconnect();
} catch (IOException e) {
    e.printStackTrace();
}