SQL ExampleAvailable as of Camel 2.11 This example is located in the examples/camel-example-sql directory of the Camel distribution. If you use maven then you can easily compile and install the example from the command line: mvn install AboutThis example shows how to exchange data using a shared database table. The example has two Camel routes. The first route insert new data into the table, triggered by a timer to run every 5th second. ImplementationIn the camel-context.xml file in the src/main/resources/META-INF/spring folder we have the Spring XML file to setup and configure the database, as well the CamelContext. Setting up database <!-- this is the JDBC data source which uses an in-memory only Apache Derby database --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="org.apache.derby.jdbc.EmbeddedDriver"/> <property name="url" value="jdbc:derby:memory:orders;create=true"/> <property name="username" value=""/> <property name="password" value=""/> </bean> <!-- bean which creates/destroys the database table for this example --> <bean id="initDatabase" class="org.apache.camel.example.sql.DatabaseBean" init-method="create" destroy-method="destroy"> <property name="dataSource" ref="dataSource"/> </bean> <!-- configure the Camel SQL component to use the JDBC data source --> <bean id="sql" class="org.apache.camel.component.sql.SqlComponent"> <property name="dataSource" ref="dataSource"/> </bean> And then in the same file we setup our Camel application. At first we have a orderBean that we use in the routes to generate new orders and process orders as well. Camel application <!-- order bean is our business logic bean that creates new orders --> <bean id="orderBean" class="org.apache.camel.example.sql.OrderBean"/> <!-- here is Camel configured with a number of routes --> <camelContext xmlns="http://camel.apache.org/schema/spring"> <!-- use Camel property placeholder loaded from the given file --> <propertyPlaceholder id="placeholder" location="classpath:sql.properties"/> <!-- route that generate new orders and insert them in the database --> <route id="generateOrder-route"> <from uri="timer:foo?period=5s"/> <transform> <method ref="orderBean" method="generateOrder"/> </transform> <to uri="sql:{{sql.insertOrder}}"/> <log message="Inserted new order ${body[id]}"/> </route> <!-- route that process the orders by picking up new rows from the database and when done processing then update the row to mark it as processed --> <route id="processOrder-route"> <from uri="sql:{{sql.selectOrder}}?consumer.onConsume={{sql.markOrder}}"/> <to uri="bean:orderBean?method=processOrder"/> <log message="${body}"/> </route> </camelContext> Notice how we have externalized the SQL queries, and use Camels property placeholder to refer to the sql.properties file.
SQL queries ## notice we use named parameters in the queries, eg :#name. A named query parameter must start with :# ## sql that insert new orders sql.insertOrder=insert into orders (id, item, amount, description, processed) values (:#id, :#item, :#amount, :#description, false) ## sql that select all unprocessed orders sql.selectOrder=select * from orders where processed = false ## sql that update the order as being processed sql.markOrder=update orders set processed = true where id = :#id Running the exampleThis example can be run from the command line mvn camel:run Press ctrl + c to stop the example. See Also |
