[CONF] Apache Camel > JDBC

[confluence]

JDBC Page edited by Claus Ibsen JDBC Component The jdbc component enables you to access databases through JDBC, where SQL queries and operations are sent in the message body. This component uses the standard JDBC API, unlike the SQL Component component, which uses spring-jdbc. This component can only be used to define producer endpoints, which means that you cannot use the JDBC component in a from() statement. URI format jdbc:dataSourceName[?options] This component only supports producer endpoints. You can append query options to the URI in the following format, ?option=value&option=value&... Options Name Default Value Description readSize 0 / 2000 The default maximum number of rows that can be read by a polling query. The default value is 2000 for Camel 1.5.0 or older. In newer releases the default value is 0. statement.<xxx> null Camel 2.1: Sets additional options on the java.sql.Statement that is used behind the scenes to execute the queries. For instance, statement.maxRows=10. For detailed documentation, see the java.sql.Statement javadoc documentation. useJDBC4ColumnNameAndLabelSemantics true Camel 1.6.3/2.2: Sets whether to use JDBC 4/3 column label/name semantics. You can use this option to turn it false in case you have issues with your JDBC driver to select data. This only applies when using SQL SELECT using aliases (e.g. SQL SELECT id as identifier, name as given_name from persons). Result The result is returned in the OUT body as an ArrayList<HashMap<String, Object>>. The List object contains the list of rows and the Map objects contain each row with the String key as the column name. Note: This component fetches ResultSetMetaData to be able to return the column name as the key in the Map. Message Headers Header Description CamelJdbcRowCount If the query is a SELECT, query the row count is returned in this OUT header. CamelJdbcUpdateCount If the query is an UPDATE, query the update count is returned in this OUT header. Samples In the following example, we fetch the rows from the customer table. First we register our datasource in the Camel registry as testdb: JndiRegistry reg = super.createRegistry(); reg.bind("testdb", ds); return reg; Then we configure a route that routes to the JDBC component, so the SQL will be executed. Note how we refer to the testdb datasource that was bound in the previous step: // lets add simple route public void configure() throws Exception { from("direct:hello").to("jdbc:testdb?readSize=100"); } Or you can create a DataSource in Spring like this: <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="timer://kickoff?period=10000"/> <setBody> <constant>select * from customer</constant> </setBody> <to uri="jdbc:testdb"/> <to uri="mock:result"/> </route> </camelContext> <!-- Just add a demo to show how to bind a date source for camel in Spring--> <bean id="testdb" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="org.hsqldb.jdbcDriver"/> <property name="url" value="jdbc:hsqldb:mem:camel_jdbc" /> <property name="username" value="sa" /> <property name="password" value="" /> </bean> We create an endpoint, add the SQL query to the body of the IN message, and then send the exchange. The result of the query is returned in the OUT body: // first we create our exchange using the endpoint Endpoint endpoint = context.getEndpoint("direct:hello"); Exchange exchange = endpoint.createExchange(); // then we set the SQL on the in body exchange.getIn().setBody("select * from customer order by ID"); // now we send the exchange to the endpoint, and receives the response from Camel Exchange out = template.send(endpoint, exchange); // assertions of the response assertNotNull(out); assertNotNull(out.getOut()); ArrayList<HashMap<String, Object>> data = "" assertNotNull("out body could not be converted to an ArrayList - was: " + out.getOut().getBody(), data); assertEquals(2, data.size()); HashMap<String, Object> row = data.get(0); assertEquals("cust1", row.get("ID")); assertEquals("jstrachan", row.get("NAME")); row = data.get(1); assertEquals("cust2", row.get("ID")); assertEquals("nsandhu", row.get("NAME")); If you want to work on the rows one by one instead of the entire ResultSet at once you need to use the Splitter EIP such as: from("direct:hello") // here we split the data from the testdb into new messages one by one // so the mock endpoint will receive a message per row in the table .to("jdbc:testdb").split(body()).to("mock:result"); Sample - Polling the database every minute If we want to poll a database using the JDBC component, we need to combine it with a polling scheduler such as the Timer or Quartz etc. In the following example, we retrieve data from the database every 60 seconds: from("timer://foo?period=60000").setBody(constant("select * from customer")).to("jdbc:testdb").to("activemq:queue:customers"); See Also Configuring Camel Component Endpoint Getting Started SQL Change Notification Preferences View Online | View Change | Add Comment