Question

我需要使用谷歌云端点上传文件到谷歌云端存储并打印回文件的URL。

我不想运行处理文件上传的独立servlet。

服务器代码如下：

import java.io.File;

public void saveFile(File upload,User auth) throws IOException {
            if (auth!=null){
                String bucketName = "app-id.appspot.com";

            GcsService gcsService = GcsServiceFactory.createGcsService(new RetryParams.Builder()
                    .initialRetryDelayMillis(10)
                    .retryMaxAttempts(10)
                    .totalRetryPeriodMillis(15000)
                    .build());

            String sname = upload.getName();
            String extension = sname.substring(sname.lastIndexOf('.'),sname.length());

            String sctype =  URLConnection.guessContentTypeFromName(upload.getName());

            String filename;
            filename = String.valueOf(Calendar.getInstance().getTimeInMillis()) + extension;

            GcsFilename gcsfileName = new GcsFilename(bucketName, filename);

            GcsFileOptions options = new GcsFileOptions.Builder()
                    .acl("public-read").mimeType(sctype).build();

            GcsOutputChannel outputChannel =
                    gcsService.createOrReplace(gcsfileName, options);

            InputStream stream = new FileInputStream(upload);

            copy(stream, Channels.newOutputStream(outputChannel));
        }
    }

    private static final int BUFFER_SIZE = 2 * 1024 * 1024;

    private void copy(InputStream input, OutputStream output) throws IOException {
        try {
            byte[] buffer = new byte[BUFFER_SIZE];
            int bytesRead = input.read(buffer);
            while (bytesRead != -1) {
                output.write(buffer, 0, bytesRead);
                bytesRead = input.read(buffer);
            }
        } finally {
            input.close();
            output.close();
        }
    }

但是当我重建项目时，导入java.io.File会在生成的客户端库中转换为com.backend.managerApi.model.File。

那么，有没有办法做到这一点，或者我们只需要运行一个独立的servlet来处理上传？

Answer 1

以防万一有人希望Servlet代码也这样做：

import com.google.appengine.tools.cloudstorage.GcsFileOptions;
import com.google.appengine.tools.cloudstorage.GcsFilename;
import com.google.appengine.tools.cloudstorage.GcsOutputChannel;
import com.google.appengine.tools.cloudstorage.GcsService;
import com.google.appengine.tools.cloudstorage.GcsServiceFactory;
import com.google.appengine.tools.cloudstorage.RetryParams;

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.channels.Channels;
import java.util.Calendar;
import java.util.logging.Logger;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class UploadServlet extends HttpServlet {

    private static final Logger log = Logger.getLogger(UploadServlet.class.getName());

    private final GcsService gcsService = GcsServiceFactory.createGcsService(new RetryParams.Builder()
            .initialRetryDelayMillis(10)
            .retryMaxAttempts(10)
            .totalRetryPeriodMillis(15000)
            .build());

    private String bucketName = "app-id.appspot.com";

    /**Used below to determine the size of chucks to read in. Should be > 1kb and < 10MB */
    private static final int BUFFER_SIZE = 2 * 1024 * 1024;

    @SuppressWarnings("unchecked")
    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {

        String sctype = null, sfieldname, sname = null;
        ServletFileUpload upload;
        FileItemIterator iterator;
        FileItemStream item;
        InputStream stream = null;
        try {
            upload = new ServletFileUpload();
            res.setContentType("text/plain");

            iterator = upload.getItemIterator(req);
            while (iterator.hasNext()) {
                item = iterator.next();
                stream = item.openStream();

                if (item.isFormField()) {
                    log.warning("Got a form field: " + item.getFieldName());
                } else {
                    log.warning("Got an uploaded file: " + item.getFieldName() +
                            ", name = " + item.getName());

                    //sfieldname = item.getFieldName();

                    sname = item.getName();
                    String extension = sname.substring(sname.lastIndexOf('.'),sname.length());

                    sctype = item.getContentType();

                    String filename;
                    filename = String.valueOf(Calendar.getInstance().getTimeInMillis()) + extension;

                    GcsFilename gcsfileName = new GcsFilename(bucketName, filename);

                    GcsFileOptions options = new GcsFileOptions.Builder()
                            .acl("public-read").mimeType(sctype).build();

                    GcsOutputChannel outputChannel =
                            gcsService.createOrReplace(gcsfileName, options);

                    copy(stream, Channels.newOutputStream(outputChannel));

                    //res.sendRedirect("/");
                    res.getWriter().print(filename);
                }
            }
        } catch (Exception ex) {
            throw new ServletException(ex);
        }
    }

    private void copy(InputStream input, OutputStream output) throws IOException {
        try {
            byte[] buffer = new byte[BUFFER_SIZE];
            int bytesRead = input.read(buffer);
            while (bytesRead != -1) {
                output.write(buffer, 0, bytesRead);
                bytesRead = input.read(buffer);
            }
        } finally {
            input.close();
            output.close();
        }
    }

}

就这样点击servlet：

curl -F file=@"picture.jpg" http://myAppEngineProj.appspot.com/myServlet

通过Google Cloud端点将文件上传到Android客户端的Google云端存储

1 个答案: