Unable to connect to Google Cloud SQL instance from Google App Engine when developing in Eclipse
Question
EDIT: This has been resolved by checking the log file on the Google Developers Console. The error was not in connecting to the database, but was because I was compiling with JDK 1.8 instead of 1.7. It turned out that even though I had told Eclipse to use JDK 1.7 for the project, it was still using 1.8 because I had the following line in my Eclipse configuration file:
-vm
C:\Program Files\Java\jdk1.8.0_20\bin
when I changed this to:
-vm
C:\Program Files\Java\jdk1.7.0_71\bin
everything worked perfectly.
Original Question:
I am trying to connect to a Google Cloud SQL instance from my authorized Google App Engine application. I started by following the directions at https://cloud.google.com/appengine/docs/java/cloud-sql/#Java_Build_a_starter_application_and_database and modifying them slightly to work with my Cloud SQL instance (I did not implement the guestbook database, I used my own which also has just one table with three columns). I created the Cloud SQL instance using MySQL Workbench.
When I debug my application locally (run it at localhost:8888) it works perfectly with my local MySQL instance AND the Google Cloud SQL instance. However, when I try to deploy my application to Google App Engine it just spits back a 500 Server Error and I have no clue what went wrong (I am very new to web programming). I have been searching all over the web for a solution to this issue but I've yet to find something that does the trick.
Here is my code for the servlet:
package com.rmpm;
import java.io.*;
import java.sql.*;
import javax.servlet.http.*;
import com.google.appengine.api.utils.SystemProperty;
@SuppressWarnings("serial")
public class Synaptic_rmpmServlet extends HttpServlet {
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
String url = null;
resp.setContentType("text/html");
PrintWriter out = resp.getWriter();
try {
if (SystemProperty.environment.value() ==
SystemProperty.Environment.Value.Production) {
// Load the class that provides the new "jdbc:google:mysql://" prefix.
Class.forName("com.mysql.jdbc.GoogleDriver");
url = "jdbc:google:mysql://<my-project-id>:<my-instance-id>/test"; // Doesn't work
} else {
// Local MySQL instance to use during development.
Class.forName("com.mysql.jdbc.Driver");
url = "jdbc:mysql://173.###.##.###:3306/test"; // Connects to Google Cloud SQL instance when root password is provided
//url = "jdbc:mysql://127.0.0.1:3306/test"; // Connects to local MySQL instance
}
} catch (Exception e) {
e.printStackTrace();
return;
}
try {
Connection conn = DriverManager.getConnection(url, "root", "");
try {
String pid = req.getParameter("projID");
String own = req.getParameter("owner");
String dur = req.getParameter("duration");
if (pid == "" || own == "" || dur == "") {
out.println(
"<html><head></head><body>You are missing either a projectID, owner name, or duration! Try again! " +
"Redirecting in 3 seconds...</body></html>");
}
else {
int duration = Integer.parseInt(dur);
String statement = "INSERT INTO project VALUES(?, ?, ?)";
PreparedStatement stmt = conn.prepareStatement(statement);
stmt.setString(1, pid);
stmt.setString(2, own);
stmt.setInt(3, duration);
int success = 2;
success = stmt.executeUpdate();
if (success == 1) {
out.println(
"<html><head></head><body>Success! Redirecting in 3 seconds...</body></html>");
} else if (success == 0) {
out.println(
"<html><head></head><body>Failure! Please try again! " +
"Redirecting in 3 seconds...</body></html>");
}
}
} finally {
conn.close();
}
}
catch (SQLException e) {
e.printStackTrace();
}
resp.setHeader("Refresh", "3; url=/databaseIO.jsp");
}
}
And my code for the databaseIO.jsp:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.util.List" %>
<%@ page import="java.sql.*" %>
<%@ page import="com.google.appengine.api.utils.SystemProperty" %>
<html>
<body>
<%
String url = null;
if (SystemProperty.environment.value() ==
SystemProperty.Environment.Value.Production) {
// Load the class that provides the new "jdbc:google:mysql://" prefix.
Class.forName("com.mysql.jdbc.GoogleDriver");
url = "jdbc:google:mysql://<my-project-id>:<my-instance-id>/test"; // Doesn't work
} else {
// Local MySQL instance to use during development.
Class.forName("com.mysql.jdbc.Driver");
url = "jdbc:mysql://173.###.##.###:3306/test"; // Connects to Google Cloud SQL instance when root password is provided
//url = "jdbc:mysql://127.0.0.1:3306/test"; // Connects to local MySQL instance
}
Connection conn = DriverManager.getConnection(url, "root", "");
ResultSet rs = conn.createStatement().executeQuery(
"SELECT * FROM project");
%>
<table style="border: 1px solid black">
<tbody>
<tr>
<th width="40%" style="background-color: #CCFFCC; margin: 5px">projectID</th>
<th style="background-color: #CCFFCC; margin: 5px">owner</th>
<th style="background-color: #CCFFCC; margin: 5px">duration</th>
</tr>
<%
while (rs.next()) {
String aPID = rs.getString(1);
String anOwner = rs.getString(2);
int aDur = rs.getInt(3);
%>
<tr>
<td><%= aPID %></td>
<td><%= anOwner %></td>
<td><%= aDur %></td>
</tr>
<%
}
conn.close();
%>
</tbody>
</table>
<br />
No more projects!
<p><strong>Add a project:</strong></p>
<form action="/sign" method="post">
<div>Project ID: <input type="text" name="projID"></input></div>
<br />
<div>Owner: <input type="text" name="owner"></input></div>
<br />
<div>Duration: <input type="text" name="duration"></input></div>
<br />
<div><input type="submit" value="Insert Project"></input></div>
</form>
</body>
</html>
Based on what I've read online, I gather that I shouldn't need a password when connecting as the root user to my Google Cloud SQL instance from my authorized Google App Engine application. When I connect to the Google Cloud SQL instance locally in debug mode, I do provide the root password which I set in the Google Developers Console and it works perfectly.
What I've done:
- I am already logged into Eclipse with the Google account that is linked to my Google App Engine application.
- I have already included the
<use-google-connector-j>true</use-google-connector-j>line in the appengine-web.xml file. - I have copied the mysql-connector-java-5.1.33-bin.jar to the project's war/WEB-INF/lib folder and to the GAE SDK directory at D:\\Program_Files\\Eclipse\\plugins\\com.google.appengine.eclipse.sdkbundle_1.9.13\\appengine-java-sdk-1.9.13\\lib\\impl (reading similar questions online said to do this).
- I have authorized my Google App Engine application to connect to my Google Cloud SQL instance.
- I have authorized my local network to connect to my Google Cloud SQL instance.
- I am 100% sure the
<my-project-id>and<my-instance-id>fields are correct in the JDBC url. - I've tried using my Google Cloud SQL instance's IP address in the JDBC url instead of the project-id and instance-id.
What I'm using:
- Eclipse SE Luna (4.4.1) with Google Plugin for Eclipse (4.4) and Google App Engine Java SDK (1.9.13). I deploy from Eclipse straight to Google App Engine with the plugin.
- JDK 1.7
- Windows 8.1 64-bit
If you need any additional information just post here as I'll be checking this regularly.
1 answers
solution1
0 2017-11-20 12:39:04
本地mysql将在您的代码上工作，我遇到了同样的问题，但是随着我将.GoogleDriver更改为.Driver，它开始起作用
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