Chapter 72. iBATIS
iBATIS
The ibatis: component allows you to query, poll, insert, update and delete data in a relational database using Apache iBATIS.
Prefer MyBatis
The Apache iBatis project is no longer active. The project is moved outside Apache and is now know as the MyBatis project. Therefore we encourage users to use MyBatis instead. This camel-ibatis component will be removed in Camel 3.0.
iBatis does not support Spring 4.x. So you can only use Spring 3.x or older with iBatis.
Maven users will need to add the following dependency to their
pom.xml for this component:
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-ibatis</artifactId>
<version>x.x.x</version>
<!-- use the same version as your Camel core version -->
</dependency>URI format
ibatis:statementName[?options]
Where statementName is the name in the iBATIS XML configuration file which maps to the query, insert, update or delete operation you wish to evaluate.
You can append query options to the URI in the following format,
?option=value&option=value&...
This component will by default load the iBatis SqlMapConfig file from the root of the classpath and expected named as
SqlMapConfig.xml. It uses Spring resource loading so you can define it using classpath, file or http as prefix to load resources with those schemes. In Camel 2.2 you can configure this on the iBatisComponent with the setSqlMapConfig(String) method.
Options
| Option | Type | Default | Description |
|---|---|---|---|
consumer.onConsume
|
String
|
null
|
Statements to run after consuming. Can be used, for example, to update rows after they have been consumed and processed in Apache Camel. See sample later. Multiple statements can be separated with comma. |
consumer.useIterator
|
boolean
|
true
|
If true each row returned when polling will be processed individually. If false the entire List of data is set as the IN body.
|
consumer.routeEmptyResultSet
|
boolean
|
false
|
Apache Camel 2.0: Sets whether empty result set should be routed or not. By default, empty result sets are not routed. |
statementType
|
StatementType
|
null
|
Apache Camel 1.6.1/2.0: Mandatory to specify for IbatisProducer to control which iBatis SqlMapClient method to invoke. The enum values are: QueryForObject, QueryForList, Insert, Update, Delete.
|
maxMessagesPerPoll
|
int
|
0
|
Apache Camel 2.0: An integer to define a maximum messages to gather per poll. By default, no maximum is set. Can be used to set a limit of e.g. 1000 to avoid when starting up the server that there are thousands of files. Set a value of 0 or negative to disabled it. |
isolation
|
String
|
TRANSACTION_REPEATABLE_READ
|
*Camel 2.9:* A String the defines the transaction isolation level of the will be used. Allowed values are TRANSACTION_NONE, TRANSACTION_READ_UNCOMMITTED, TRANSACTION_READ_COMMITTED, TRANSACTION_REPEATABLE_READ, TRANSACTION_SERIALIZABLE |
isolation
|
String
|
TRANSACTION_REPEATABLE_READ
|
*Camel 2.9:* A String the defines the transaction isolation level of the will be used. Allowed values are TRANSACTION_NONE, TRANSACTION_READ_UNCOMMITTED, TRANSACTION_READ_COMMITTED, TRANSACTION_REPEATABLE_READ, TRANSACTION_SERIALIZABLE |
Message Headers
Apache Camel will populate the result message, either IN or OUT with a header with the operationName used:
| Header | Type | Description |
|---|---|---|
CamelIBatisStatementName
|
String
|
Apache Camel 2.0: The statementName used (for example: insertAccount). |
CamelIBatisResult
|
Object
|
Apache Camel 1.6.2/2.0: The response returned from iBatis in any of the operations. For instance an INSERT could return the auto-generated key, or number of rows etc.
|
Message Body
Apache Camel 1.6.2/2.0: The response from iBatis will only be set as body if it's a
SELECT statement. That means, for example, for INSERT statements Apache Camel will not replace the body. This allows you to continue routing and keep the original body. The response from iBatis is always stored in the header with the key CamelIBatisResult.
Samples
For example if you wish to consume beans from a JMS queue and insert them into a database you could do the following:
from("activemq:queue:newAccount").
to("ibatis:insertAccount?statementType=Insert");
Notice we have to specify the
statementType, as we need to instruct Apache Camel which SqlMapClient operation to invoke.
Where insertAccount is the iBatis ID in the SQL map file:
<!-- Insert example, using the Account parameter class -->
<insert id="insertAccount" parameterClass="Account">
insert into ACCOUNT (
ACC_ID,
ACC_FIRST_NAME,
ACC_LAST_NAME,
ACC_EMAIL
)
values (
#id#, #firstName#, #lastName#, #emailAddress#
)
</insert>Using StatementType for better control of IBatis
Available as of Apache Camel 1.6.1/2.0 When routing to an iBatis endpoint you want more fine grained control so you can control whether the SQL statement to be executed is a
SELEECT, UPDATE, DELETE or INSERT etc. This is now possible in Apache Camel 1.6.1/2.0. So for instance if we want to route to an iBatis endpoint in which the IN body contains parameters to a SELECT statement we can do:
from("direct:start")
.to("ibatis:selectAccountById?statementType=QueryForObject")
.to("mock:result");
In the code above we can invoke the iBatis statement
selectAccountById and the IN body should contain the account id we want to retrieve, such as an Integer type.
We can do the same for some of the other operations, such as
QueryForList:
from("direct:start")
.to("ibatis:selectAllAccounts?statementType=QueryForList")
.to("mock:result");
And the same for
UPDATE, where we can send an Account object as IN body to iBatis:
from("direct:start")
.to("ibatis:updateAccount?statementType=Update")
.to("mock:result");
Scheduled polling example
Since this component does not support scheduled polling, you need to use another mechanism for triggering the scheduled polls, such as the Timer or Quartz components.
In the sample below we poll the database, every 30 seconds using the Timer component and send the data to the JMS queue:
from("timer://pollTheDatabase?delay=30000").to("ibatis:selectAllAccounts?statementType=QueryForList").to("activemq:queue:allAccounts");
And the iBatis SQL map file used:
<!-- Select with no parameters using the result map for Account class. -->
<select id="selectAllAccounts" resultMap="AccountResult">
select * from ACCOUNT
</select>Using onConsume
This component supports executing statements after data have been consumed and processed by Apache Camel. This allows you to do post updates in the database. Notice all statements must be
UPDATE statements. Apache Camel supports executing multiple statements whose name should be separated by comma.
The route below illustrates we execute the consumeAccount statement data is processed. This allows us to change the status of the row in the database to processed, so we avoid consuming it twice or more.
from("ibatis:selectUnprocessedAccounts?consumer.onConsume=consumeAccount").to("mock:results");
And the statements in the sqlmap file:
<select id="selectUnprocessedAccounts" resultMap="AccountResult">
select * from ACCOUNT where PROCESSED = false
</select><update id="consumeAccount" parameterClass="Account">
update ACCOUNT set PROCESSED = true where ACC_ID = #id#
</update>