Chapter 50. JDBC

JDBC Component
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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.

Warning

This component can only be used to define producer endpoints, which means that you cannot use the JDBC component in a from() statement.

Important

This component can not be used as a Transactional Client. If you need transaction support in your route, you should use the SQL component instead.

URI format
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jdbc:dataSourceName[?options]

jdbc:dataSourceName[?options]

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This component only supports producer endpoints.

You can append query options to the URI in the following format, ?option=value&option=value&...

Options
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Name	Default Value	Description
`readSize`	`0`	The default maximum number of rows that can be read by a polling query.
`statement.<xxx>`	`null`	Apache 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`	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`).
`resetAutoCommit`	`true`	Camel 2.9: Camel will set the autoCommit on the JDBC connection to be false, commit the change after executed the statement and reset the autoCommit flag of the connection at the end, if the resetAutoCommit is true. If the JDBC connection doesn't support to reset the autoCommit flag, you can set the resetAutoCommit flag to be false, and Camel will not try to reset the autoCommit flag.

Result
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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
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Header	Description
`CamelJdbcRowCount`	If the query is a `SELECT`, the row count is returned in this OUT header.
`CamelJdbcUpdateCount`	If the query is an `UPDATE`, the update count is returned in this OUT header.
`CamelGeneratedKeysRows`	Camel 2.10: Rows that contains the generated kets.
`CamelGeneratedKeysRowCount`	Camel 2.10: The number of rows in the header that contains generated keys.

Generated keys
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Available as of Camel 2.10

If you insert data using SQL INSERT, then the RDBMS may support auto generated keys. You can instruct the JDBC producer to return the generated keys in headers. To do that set the header CamelRetrieveGeneratedKeys=true. Then the generated keys will be provided as headers with the keys listed in the table above.

You can see more details in this unit test.

Samples
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In the following example, we fetch the rows from the customer table.

First we register our datasource in the Apache Camel registry as testdb:

JndiRegistry reg = super.createRegistry();
reg.bind("testdb", db);
return reg;

JndiRegistry reg = super.createRegistry();
reg.bind("testdb", db);
return reg;

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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");
}

// lets add simple route
public void configure() throws Exception {
    from("direct:hello").to("jdbc:testdb?readSize=100");
}

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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-->
<jdbc:embedded-database id="testdb" type="DERBY">
	<jdbc:script location="classpath:sql/init.sql"/>
</jdbc:embedded-database>

<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-->
<jdbc:embedded-database id="testdb" type="DERBY">
	<jdbc:script location="classpath:sql/init.sql"/>
</jdbc:embedded-database>

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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());
List<Map<String, Object>> data = out.getOut().getBody(List.class);
assertNotNull(data);
assertEquals(3, data.size());
Map<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"));

// 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());
List<Map<String, Object>> data = out.getOut().getBody(List.class);
assertNotNull(data);
assertEquals(3, data.size());
Map<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"));

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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");

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");

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Sample - Polling the database every minute
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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");

from("timer://foo?period=60000").setBody(constant("select * from customer")).to("jdbc:testdb").to("activemq:queue:customers");

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이 콘텐츠는 선택한 언어로 제공되지 않습니다.

JDBC Component
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URI format
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Options
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Result
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Message Headers
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Generated keys
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Samples
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Sample - Polling the database every minute
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이 콘텐츠는 선택한 언어로 제공되지 않습니다.

Chapter 50. JDBC

JDBC Component링크 복사링크가 클립보드에 복사되었습니다!

URI format링크 복사링크가 클립보드에 복사되었습니다!

Options링크 복사링크가 클립보드에 복사되었습니다!

Result링크 복사링크가 클립보드에 복사되었습니다!

Message Headers링크 복사링크가 클립보드에 복사되었습니다!

Generated keys링크 복사링크가 클립보드에 복사되었습니다!

Samples링크 복사링크가 클립보드에 복사되었습니다!

Sample - Polling the database every minute링크 복사링크가 클립보드에 복사되었습니다!

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JDBC Component
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URI format
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Options
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Result
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Message Headers
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Generated keys
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Samples
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Sample - Polling the database every minute
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