Java中的数据存储区导出逻辑

本文介绍了Java中的数据存储区导出逻辑的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 感谢Google宣布了Cloud Datastore的导出逻辑。我想在我的平台上设置schedule-export。但是，它不是Python，而是Java。因此，我需要使用cron.xml和Java逻辑来设计此逻辑。 Thankfully, Google announced the export logic from cloud Datastore. I would like to set up schedule-export in my platform. However, it's not Python, but Java. So I need to use cron.xml and Java logic to design this logic. 在Java中是否有参考设计数据存储导出逻辑（cloud_datastore_admin.py）？特别是，我需要用Java转换这部分Is there any reference to design Datastore export logic (cloud_datastore_admin.py) in Java? Especially, I need to transform this part in Javaapp = webapp2.WSGIApplication([ ('/cloud-datastore-export', Export),], debug=True) https://cloud.google.com/datastore/docs/schedule-export 推荐答案您可以通过遵循这些说明。一次您有了骨架，添加类似以下内容以处理导出请求：Once you have the skeleton, add something like this to handle export requests: CloudDatastoreExport.java package com.google.example.datastore;import com.google.appengine.api.appidentity.AppIdentityService;import com.google.appengine.api.appidentity.AppIdentityServiceFactory;import com.google.apphosting.api.ApiProxy;import com.google.common.io.CharStreams;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.HttpURLConnection;import java.net.URL;import java.nio.charset.StandardCharsets;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Date;import java.util.logging.Logger;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.json.JSONArray;import org.json.JSONObject;import org.json.JSONTokener;@WebServlet(name = "CloudDatastoreExport", value = "/cloud-datastore-export")public class CloudDatastoreExport extends HttpServlet { private static final Logger log = Logger.getLogger(CloudDatastoreExport.class.getName()); @Override public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { // Verify outputURL parameter String outputUrlPrefix = request.getParameter("output_url_prefix"); if (outputUrlPrefix == null || !outputUrlPrefix.matches("^gs://.*")) { response.setStatus(HttpServletResponse.SC_CONFLICT); response.setContentType("text/plain"); response.getWriter().println("Error: Must provide a valid output_url_prefix."); } else { // Get project ID String projectId = ApiProxy.getCurrentEnvironment().getAppId(); // Remove partition information to get plain app ID String appId = projectId.replaceFirst("(.*~)", ""); // Get access token ArrayList<String> scopes = new ArrayList<String>(); scopes.add("https://www.googleapis.com/auth/datastore"); final AppIdentityService appIdentity = AppIdentityServiceFactory.getAppIdentityService(); final AppIdentityService.GetAccessTokenResult accessToken = appIdentity.getAccessToken(scopes); // Read export parameters // If output prefix does not end with slash, add a timestamp if (!outputUrlPrefix.substring(outputUrlPrefix.length() - 1).contentEquals("/")) { String timeStamp = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date()); outputUrlPrefix = outputUrlPrefix + "/" + timeStamp + "/"; } String[] namespaces = request.getParameterValues("namespace_id"); String[] kinds = request.getParameterValues("kind"); // Build export request JSONObject exportRequest = new JSONObject(); exportRequest.put("output_url_prefix", outputUrlPrefix); JSONObject entityFilter = new JSONObject(); if (kinds != null) { JSONArray kindsJSON = new JSONArray(kinds); entityFilter.put("kinds", kinds); } if (namespaces != null) { JSONArray namespacesJSON = new JSONArray(namespaces); entityFilter.put("namespaceIds", namespacesJSON); } exportRequest.put("entityFilter", entityFilter); URL url = new URL("https://datastore.googleapis.com/v1/projects/" + appId + ":export"); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setDoOutput(true); connection.setRequestMethod("POST"); connection.addRequestProperty("Content-Type", "application/json"); connection.addRequestProperty("Authorization", "Bearer " + accessToken.getAccessToken()); OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream()); exportRequest.write(writer); writer.close(); if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) { JSONTokener exportResponseTokens = new JSONTokener(connection.getInputStream()); JSONObject exportResponse = new JSONObject(exportResponseTokens); response.setContentType("text/plain"); response.getWriter().println("Export started:\n" + exportResponse.toString(4)); } else { InputStream s = connection.getErrorStream(); InputStreamReader r = new InputStreamReader(s, StandardCharsets.UTF_8); String errorMessage = String.format( "got error (%d) response %s from %s", connection.getResponseCode(), CharStreams.toString(r), connection.toString()); log.warning(errorMessage); response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); response.setContentType("text/plain"); response.getWriter().println("Failed to initiate export."); } } }}您可以从文档中使用相同的 cron.yaml ：You can use the same cron.yaml from the docs:cron:- description: "Daily Cloud Datastore Export" url: /cloud-datastore-export?namespace_id=&output_url_prefix=gs://BUCKET_NAME[/NAMESPACE_PATH] target: cloud-datastore-admin schedule: every 24 hours使用gcloud部署cron作业：Use gcloud to deploy the cron job:gcloud app deploy cron.yaml请确保完成此部分以提供GAE导出和存储桶权限，否则会出现权限被拒绝错误：Make sure you complete this part to give GAE export and bucket permissions or elseyou'll get permission denied errors: https://cloud.google.com/datastore/docs/schedule-export#before_you_begin 这篇关于Java中的数据存储区导出逻辑的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！