使用 url.openConnection、IOUtils.write 从网站下载文件与本地文件对比

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.junit.Test;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.util.Collection;

public class TestMain {

    /**
     * 使用 url.openConnection、IOUtils.write 从网站下载文件与本地文件对比
     *
     * @throws IOException
     */
    @Test
    public void test() throws IOException {
        String httpPrefix = "https://xxx.com.cn";
        File dist = new File("C:\Users\Nihaorz\Desktop\dist");
        File distNew = new File("C:\Users\Nihaorz\Desktop\dist-new");
        if (!distNew.exists()) {
            FileUtils.forceMkdir(distNew);
        } else {
            if (!distNew.isDirectory()) {
                throw new RuntimeException(String.format("【%s】不是文件夹，请新建【%s】文件夹", distNew.getAbsolutePath(), distNew.getAbsolutePath()));
            }
            if (distNew.listFiles().length > 0) {
                throw new RuntimeException(String.format("【%s】文件夹不为空，请清空文件夹后再试", distNew.getAbsolutePath()));
            }
        }
        Collection<File> files = FileUtils.listFiles(dist, null, true);
        int i = 0;
        for (File file : files) {
            String filename = file.getAbsolutePath();
            // 跳过目录和.git文件夹下的内容
            if (file.isFile() && !filename.startsWith("C:\Users\Nihaorz\Desktop\dist\.git")) {
                URL url = new URL(httpPrefix + file.getAbsolutePath().substring(dist.getAbsolutePath().length()).replace(File.separator, "/"));
                File outFile = new File(file.getAbsolutePath().replace(dist.getAbsolutePath(), distNew.getAbsolutePath()));
                FileUtils.forceMkdirParent(outFile);
                try {
                    IOUtils.write(IOUtils.toByteArray(url.openConnection().getInputStream()), new FileOutputStream(outFile));
                    System.out.println(String.format("【%s】文件下载完毕", url.toString()));
                } catch (FileNotFoundException e) {
                    System.err.println(String.format("【%s】文件不存在", url.toString()));
                    i++;
                } catch (IOException e) {
                    e.printStackTrace();
                    i++;
                }
            }
        }
        System.out.println(String.format("所有文件处理完毕，其中【%d】个文件下载失败", i));
    }

}