使用Java/eclipse的Google Cloud SQL和Google App Engine：必须设置系统属性rdbms.driver

我在使用google app engine访问使用google Cloud SQL创建的数据库时遇到了一些问题。我觉得问题在于我试图使用的JSP文件以及我的导入选项。我得到的错误如下：

HTTP ERROR 500
Problem accessing /beer.jsp. Reason: 

    System property rdbms.driver must be set.

Caused by:
java.lang.IllegalStateException: System property rdbms.driver must be set.
    at com.google.appengine.api.rdbms.dev.LocalRdbmsServiceLocalDriver.registerDriver(LocalRdbmsServiceLocalDriver.java:80)
    at com.google.appengine.api.rdbms.dev.LocalRdbmsServiceLocalDriver.init(LocalRdbmsServiceLocalDriver.java:73)
    at com.google.appengine.api.rdbms.dev.LocalRdbmsService.init(LocalRdbmsService.java:85)
    at com.google.appengine.tools.development.ApiProxyLocalImpl.startServices(ApiProxyLocalImpl.java:581)
    at com.google.appengine.tools.development.ApiProxyLocalImpl.access$700(ApiProxyLocalImpl.java:46)
    at com.google.appengine.tools.development.ApiProxyLocalImpl$2.run(ApiProxyLocalImpl.java:564)
    at com.google.appengine.tools.development.ApiProxyLocalImpl$2.run(ApiProxyLocalImpl.java:562)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.ApiProxyLocalImpl.getService(ApiProxyLocalImpl.java:561)
    at com.google.appengine.tools.development.ApiProxyLocalImpl.resolveDeadline(ApiProxyLocalImpl.java:233)
    at com.google.appengine.tools.development.ApiProxyLocalImpl.doAsyncCall(ApiProxyLocalImpl.java:214)
    at com.google.appengine.tools.development.ApiProxyLocalImpl.makeSyncCall(ApiProxyLocalImpl.java:147)
    at com.google.apphosting.api.ApiProxy.makeSyncCall(ApiProxy.java:101)
    at com.google.appengine.api.rdbms.RdbmsApiProxyClient$ApiProxyBlockingInterface.makeSyncCall(RdbmsApiProxyClient.java:89)
    at com.google.appengine.api.rdbms.RdbmsApiProxyClient$ApiProxyBlockingInterface.openConnection(RdbmsApiProxyClient.java:75)
    at com.google.cloud.sql.jdbc.internal.SqlProtoClient.openConnection(SqlProtoClient.java:58)
    at com.google.cloud.sql.jdbc.Driver.connect(Driver.java:59)
    at com.google.cloud.sql.jdbc.Driver.connect(Driver.java:26)
    at java.sql.DriverManager.getConnection(DriverManager.java:579)
    at java.sql.DriverManager.getConnection(DriverManager.java:243)
    at org.apache.jsp.beer_jsp._jspService(beer_jsp.java:66)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at com.google.appengine.tools.development.PrivilegedJspServlet.access$101(PrivilegedJspServlet.java:23)
    at com.google.appengine.tools.development.PrivilegedJspServlet$2.run(PrivilegedJspServlet.java:59)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:57)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:60)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:78)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:362)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)


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我尝试了一些方法来解决这个问题，比如将mysql连接器加载到项目的引导程序中，这会导致不同的错误。我觉得这一次更接近我想要达到的结果

HTTP ERROR 500
Problem accessing /beer.jsp. Reason: 

    java.sql.SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

Caused by:
javax.servlet.ServletException: java.sql.SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:862)
    at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:791)
    at org.apache.jsp.beer_jsp._jspService(beer_jsp.java:114)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at com.google.appengine.tools.development.PrivilegedJspServlet.access$101(PrivilegedJspServlet.java:23)
    at com.google.appengine.tools.development.PrivilegedJspServlet$2.run(PrivilegedJspServlet.java:59)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:57)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:60)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:78)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:362)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.sql.SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.google.cloud.sql.jdbc.internal.Exceptions.newSqlException(Exceptions.java:208)
    at com.google.cloud.sql.jdbc.internal.SqlProtoClient.check(SqlProtoClient.java:158)
    at com.google.cloud.sql.jdbc.internal.SqlProtoClient.openConnection(SqlProtoClient.java:60)
    at com.google.cloud.sql.jdbc.Driver.connect(Driver.java:59)
    at com.google.cloud.sql.jdbc.Driver.connect(Driver.java:26)
    at java.sql.DriverManager.getConnection(DriverManager.java:579)
    at java.sql.DriverManager.getConnection(DriverManager.java:243)
    at org.apache.jsp.beer_jsp._jspService(beer_jsp.java:66)
    ... 39 more

Caused by:
java.sql.SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.google.cloud.sql.jdbc.internal.Exceptions.newSqlException(Exceptions.java:208)
    at com.google.cloud.sql.jdbc.internal.SqlProtoClient.check(SqlProtoClient.java:158)
    at com.google.cloud.sql.jdbc.internal.SqlProtoClient.openConnection(SqlProtoClient.java:60)
    at com.google.cloud.sql.jdbc.Driver.connect(Driver.java:59)
    at com.google.cloud.sql.jdbc.Driver.connect(Driver.java:26)
    at java.sql.DriverManager.getConnection(DriverManager.java:579)
    at java.sql.DriverManager.getConnection(DriverManager.java:243)
    at org.apache.jsp.beer_jsp._jspService(beer_jsp.java:66)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at com.google.appengine.tools.development.PrivilegedJspServlet.access$101(PrivilegedJspServlet.java:23)
    at com.google.appengine.tools.development.PrivilegedJspServlet$2.run(PrivilegedJspServlet.java:59)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:57)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:60)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:78)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:362)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)


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还有我的web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
              http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5"
         xmlns="http://java.sun.com/xml/ns/javaee">

  <!-- Servlets -->
  <servlet>
    <servlet-name>DBConnect</servlet-name>
    <servlet-class>beer.client.DBConnect</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>DBConnect</servlet-name>
    <url-pattern>/beer/good</url-pattern>
  </servlet-mapping>

  <!-- Default page to serve -->
  <welcome-file-list>
    <welcome-file>beer.jsp</welcome-file>
  </welcome-file-list>

</web-app>

数据库连接
beer.client.DBConnect
数据库连接
/啤酒/好的
beer.jsp

最后是我的beer.jsp文件

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.util.List" %>
<%@ page import="java.sql.*" %>
<%@ page import="com.google.appengine.api.rdbms.AppEngineDriver" %>

<html>
  <body>

<%
Connection c = null;
c = DriverManager.getConnection("jdbc:google:rdbms://asu.edu:cst433team1:team1db/mysql");
ResultSet rs = c.createStatement().executeQuery("SELECT * FROM Beers"); %>

<table style="border: 1px solid black">
<tbody>
<tr>
<th width="35%" style="background-color: #CCFFCC; margin: 5px">Name</th>
<th style="background-color: #CCFFCC; margin: 5px">Message</th>
<th style="background-color: #CCFFCC; margin: 5px">ID</th>
</tr> <%
while (rs.next()){
    int beerID = rs.getInt("beerID");
    int breweryID = rs.getInt("breweryID");
    String beerName = rs.getString("beerName");
    String style = rs.getString("Style"); %>



<tr>
    <td><%= beerID %></td>
    <td><%= breweryID %></td>
    <td><%= beerName %></td>
</tr>

<% }
c.close(); %>

</tbody>
</table>
<br />
No more messages!
  </body>
</html>

名称
消息
身份证件


没有更多的消息！

---

我对使用eclipse的API插件非常陌生，所以我不确定我们还需要什么其他信息来了解这里发生了什么。但如果这还不够，我会尽我所能提供一切。另外，我为信息量的模糊表示歉意，这是我必须与自己一起工作的全部内容。

这是MySQl的问题，它会在一定的空闲时间（默认情况下可能是8小时）后断开连接

---

因此，您需要定期执行使连接处于活动状态的任何虚拟查询，或者使用线程池

我也遇到过同样的问题，幸运的是以下解决方案帮助了我

检查您的Google Cloud SQL设置是否具有正确的实例名、帐户名和密码

右键单击project->Google->AppEngine->检查Google云SQL部分 提及

还要检查您是否有权访问该实例

---

如果您确定数据库已创建，则可以检查eclispe的设置

项目名称->谷歌->应用引擎设置->谷歌云SQL

选中“启用谷歌云SQL”并设置一些内容

---

e、 g实例名称和数据库名称。。。等等。

beer.jsp不是在进行查询吗？SQL新手here.ResultSet rs=c.createStatement（）.executeQuery（“从啤酒中选择*）；但在那个时候，连接似乎已经断开了。在运行我的程序之前，我从API控制台进行了一些手动查询。同样的错误：(