Develop Reference

AWS Lambda Java, connect to MySQL RDS

I need to develop an AWS Lambda Java function to retrieve some records from RDS MySQL database.
Should I use JDBC? Should I use the standard JDBC example:
try {
String url = "jdbc:msql://200.210.220.1:1114/Demo";
Connection conn = DriverManager.getConnection(url,"","");
Statement stmt = conn.createStatement();
ResultSet rs;
rs = stmt.executeQuery("SELECT Lname FROM Customers WHERE Snum = 2001");
while ( rs.next() ) {
String lastName = rs.getString("Lname");
System.out.println(lastName);
}
conn.close();
} catch (Exception e) {
System.err.println("Got an exception! ");
System.err.println(e.getMessage());
}

Step 1:
login IAM console
roles -> create new roles
role name :lambda-vpc-execution-role
AWS service roles ->
a) Select aws lambda
b) Attach policy "AWSLambdaFullAccess"
Step 2:
Get code from https://github.com/vinayselvaraj/lambda-jdbc-sample (note this is maven project)
Right click on project select Run as --->5.maven build...
for goal provide name package shade:shade
Go to project folder and target/lamda-0.0.1-SNAPSHOT-shaded.jar
Step 3:
Login to lambda console(skip blueprint)
Create new lambda
name: time-test
a) runtime-java
b) upload .zip(.jar) file (target/lamda-0.0.1-SNAPSHOT-shaded.jar)
Provide package.class-name::myhandler -> Handler
Role -> lambda-vpc-exceution-role
vpc provide rds-vpc details (this should work in same vpc group)
Create function
In the Action drop down list select configure test event
result will shown down like this "Execution result: succeeded (logs)"

Yes, you need to use standard JDBC code in your lambda function class. The code you provided looks okay. There are a few more things you need to do when accessing RDS or any other RDBMS through a Lamda function -
Create a jar or a zip file for your Lambda function
Your zip file needs to have a lib folder in which your JDBC driver file goes. The Lambda function doc says this is one of the two standard ways, but it didn't work for me.
You can create a jar file in which the driver classes are put in. This works. The best way to do it is through the Maven Shade plugin, which extracts the JDBC drivers and packs the classes in one single jar file.
Setup the handler function and specify it at the time of Lambda deployment
Define execution role and VPC as needed.
Upload and publish your jar or zip file.
You can test the Lambda function through the console, and see the actual output in the CloudWatch logs.

You could use this kinda implementation:
public static DataSource getDataSource(){
Utils._logger.log("Get data source");
MysqlDataSource mysqlDs = null;
try{
mysqlDs = new MysqlDataSource();
mysqlDs.setURL('jdbc:msql://'+'url');
mysqlDs.setUser('user');
mysqlDs.setPassword('pwd');
Utils._logger.log("Object "+mysqlDs.getUrl()+" "+mysqlDs.getUser()+" ");
return mysqlDs;
}
catch(Exception e) {
Utils._logger.log("No se pudo abrir el archivo de properties");
e.printStackTrace();
}
return mysqlDs;
}

One thing I am particularly noticing in your codebase is that even when you use this Lambda function for connecting to the specific RDS you have, the hostname may not be the correct one for Amazon RDS.
It needs to be the endpoint of the RDS you are trying to connect to and your complete connection url would look something like this below -
//jdbc:mysql://hostname (endpoint of RDS):port/databasename
String url = "jdbc:mysql://"+dbHost+":3306/"+dbName;
Since those endpoints can change for different databases and servers, you can make them as environment variables within Lambda and refer using
String dbHost = System.getenv("dbHost");
String dbName = System.getenv("dbName");
for a much cleaner and stateless design that Lambda supports.

Connection to oracle database

Hi I am new enough to java and I am trying to create a connection from it to my sql database. using Netbeans I managed to set up a connection easily enough. The issue is when I try to connect using my code I get driver not found. Is there something wrong with what I have?
//function to execute the insert update delete query
public void theQuery(String query){
Connection con = null;
Statement st = null;
try{
con = DriverManager.getConnection("jdbc:oracle:thin:#redwood.ict.ad.dit.ie:1521:pdb12c.ict.ad.dit.ie", "eocribin","");
st = con.createStatement();
st.executeUpdate(query);
JOptionPane.showMessageDialog(null,"Query Executed");
}catch(Exception ex){
JOptionPane.showMessageDialog(null,ex.getMessage());
}
}

you have to add oracle thin driver into your projects library and then restart the IDE to take notice of changes. Make sure that oracle's server is running when you run this code. Also check the username and password.
Java Persistence in netbeans is a much better option then using Oracle thin driver in your code. Because it saves much of your time typing and harcoding. JPA(Java Persistence API) allows you to easily add the oracle's thin driver from its menu and reduces much of your time. It is used in enterprise applications . You should try this and watch its tutorials on the following site.
These are called JPA tutorials.
http://www.programming-simplified.com

Accessing a Microsoft Access database that is saved in the classpath

I am trying to access a database that is stored in the classpath. I have installed ucanaccess 3.0.0 and all the required .jars.
My project hierarchy:
:
Here is the code I have so far:
public void login()
{
Connection conn;
try {
conn = DriverManager.getConnection("jdbc:ucanaccess:/database/theDB.accdb");
Statement s = conn.createStatement();
ResultSet rs = s.executeQuery("SELECT Student_Number FROM User");
while (rs.next()) {
System.out.println(rs.getString(1));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
It's a simple login screen and I'm just testing the connection to the databse on a button click. I understand that referencing an absolute file-path is not good, so I thought having the file in the classpath would be better.
I am getting the error
No suitable driver found for jdbc:ucanaccess:file:/C:/Users/Gandalf/workspace/FubbleApp/bin/database/theDB.accdb
So I think it must be the "/database/theDB.accdb" but I am not sure how to fix this issue.
Any help is appreciated. Thanks in advance

The path to the database file (.accdb or .mdb) that you provide in your connection URL must be either
an absolute path, or
a relative path from the current working directory that is in effect when your application is running, which in your case appears to be "C:/Users/Gandalf/workspace/FubbleApp/bin/".
If you want your application to automatically search the CLASSPATH for the database file you will need to either provide your own code to do that or include some third-party code to do the search for you.

I think that the accdb has to be outside of the jar file. and I'm saying this because jdbc is a protocol and you must be able to write in the db and writing in a db inside an archive you have to unarchive and archive the db again. I don't think you can do it easily... the solution is... relative to jar or absolute path. (in the same folder with the jar file)

How do I edit MS Access database using Java (NetBeans)

I'm trying to edit an MS Access database using some Java code (running NetBeans 7.2.1). I set up the data source and linked it to my database ProjectDatabase using the ODBC tool and named the data source DB, then i run the following code:
import java.sql.*;
public class NewMain {
public static void main(String[] args) {
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con = DriverManager.getConnection("jdbc:odbc:DB");
Statement st=con.createStatement();
String name="roseindia";
String address="delhi";
int i=st.executeUpdate("insert into user(name,address) values('"+name+"','"+address+"')");
System.out.println("Row is added");
}
catch(Exception e){
System.out.println(e);
}
}
}
The code runs without and error and returns the "Row is added" message. The problem is that when I go back to view the database the changes have not taken effect. I have tried this with a code for deleting the data, also to no effect. Has anybody had this problem and knows how to solve it?
I'm running Windows 7 64-bit, Microsoft Office 64-bit with all the 64-bit drivers and I have been unable to find any mention of this problem through web searches.
Thanks in advance for any help =)

First of all you are not closing the connection, so that is one problem. Also change your code to:
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con = DriverManager.getConnection("jdbc:odbc:DB");
Statement st=con.createStatement();
con.setAutoCommit(false); //Notice change here
String name="roseindia";
String address="delhi";
int i=st.executeUpdate("insert into user(name,address) values('"+name+"','"+address+"')");
con.commit(); //Notice change here
System.out.println("Row is added");
con.close(); //Notice change here
This will commit the changes to access database, so now you should be able to see data in MS Access.
Read here to know more about best practices for Closing and Releasing JDBC resources

integrate ms access and mysql in java

I have a problem connecting to MS Access and MySQL using Java. My problem is that I cannot find the driver for MySQL. Here is my code:
<%# page import="java.sql.*" %>
<%
Connection odbcconn = null;
Connection jdbcconn = null;
PreparedStatement readsms = null;
PreparedStatement updsms = null;
ResultSet rsread = null;
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //load database driver
odbcconn = DriverManager.getConnection("jdbc:odbc:SMS"); //connect to database
readsms = odbcconn.prepareStatement("select * from inbox where Status='New'");
rsread = readsms.executeQuery();
while(rsread.next()){
Class.forName("com.mysql.jdbc.Driver");
jdbcconn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bakme", "root", ""); //connect to database
updsms = jdbcconn.prepareStatement("insert into inbox(sms,phone) values (?,?)");
updsms.setString(1, rsread.getString("Message"));
updsms.setString(2, rsread.getString("Phone"));
updsms.executeUpdate();
}
%>

Thus, you get a ClassNotFoundException on the MySQL JDBC driver class? Then you need to put the MySQL JDBC driver JAR file containing that class in the classpath. In case of a JSP/Servlet application, the classpath covers under each the webapplication's /WEB-INF/lib folder. Just drop the JAR file in there. Its JDBC driver is also known as Connector/J. You can download it here.
That said, that's really not the way how to use JDBC and JSP together. This doesn't belong in a JSP file. You should be doing this in a real Java class. The JDBC code should also be more robust written, now it's leaking resources.

BalusC is spot on: this is not the way you should write something like this.
Connection, Statement, and ResultSet all represent finite resources. They are not like memory allocation; the garbage collector does not clean them up. You have to do that in your code, like this:
// Inside a method
Connection connection = null;
Statement statement = null;
ResultSet rs = null;
try
{
// interact with the database using connection, statement, and rs
}
finally
{
// clean up resources in a finally block using static methods,
// called in reverse order of creation, that don't throw exceptions
close(rs);
close(statement);
close(connection);
}
But if you do decide to move this to a server-side component, you're bound to have huge problems with code like this:
while(rsread.next())
{
Class.forName("com.mysql.jdbc.Driver");
jdbcconn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bakme", "root", ""); //connect to database
updsms = jdbcconn.prepareStatement("insert into inbox(sms,phone) values (?,?)");
updsms.setString(1, rsread.getString("Message"));
updsms.setString(2, rsread.getString("Phone"));
updsms.executeUpdate();
}
Registering the driver, creating a connection, without closing it, and repeatedly preparing a statement inside a loop for every row that you get out of Access shows a serious misunderstanding of relational databases and JDBC.
You should register the driver and create connections once, do what needs to be done, and clean up all the resources you've used.
If you absolutely MUST do this in a JSP, I'd recommend using JNDI data sources for both databases so you don't have to set up connections inside the page. You should not be writing scriptlet code - better to learn JSTL and use its <sql> tags.

You can use this link to download the MySql Driver. Once you download it, you need to make sure it is on the class path for the web server that you are using. The particulars of configuring JDBC drivers for a server vary from server to server. You may want to edit your question to include more details to get a better answer.