如何为 Spring Integration JDBC outbound-channel-adapter 创建动态查询? [英] How can I create a dynamic query for Spring Integration JDBC outbound-channel-adapter?

问题描述

我需要创建一个由 jdbc:outbound-channel-adapter 执行的动态更新语句，因为我需要使用具有可变数量条件的 case 表达式设置一个字段，如下所示:

I need to create a dynamic update statement to be be executed by a jdbc:outbound-channel-adapter, because I need to set one field using a case expression that has variable number of conditions as follows:

UPDATE tableA
SET    fieldA = CASE
                   WHEN fieldB IN ('a','b') THEN 1
                   WHEN fieldB IN ('c','d') THEN 2
                   ...
                   WHEN fieldB IN (...) THEN N
                END
WHERE  fieldC = :headers[MY_FIELDC]

我可以在 Spring 表达式中创建这个动态更新语句，如下所示:

I can create this dynamic update statement in a Spring expression as follows:

"'UPDATE tableA SET fieldA = ' + headers[MY_CASE_EXP] + ' WHERE fieldC = :headers[MY_FIELDC]'"

但查询属性似乎不支持Spring表达式.

But the query attribute does not seem to support Spring expressions.

如何生成供 jdbc:outbound-channel-adapter 使用的动态查询?

How can I generate a dynamic query for use by the jdbc:outbound-channel-adapter?

推荐答案

为了动态创建查询，需要使用ExpressionEvaluatingSqlParameterSourceFactory，如下所示:

In order to create query dynamically, you need to use ExpressionEvaluatingSqlParameterSourceFactory, something like below:

<jdbc:outbound-channel-adapter data-source="dataSource" channel="outboundJdbcChannelOne"
    query="UPDATE tableA SET fieldA = :something WHERE fieldC = :somethingElse"
    sql-parameter-source-factory="spelSource"/>

<bean id="spelSource" class="org.springframework.integration.jdbc.ExpressionEvaluatingSqlParameterSourceFactory">
    <property name="parameterExpressions">
        <map>
            <entry key="something" value="headers['MY_CASE_EXP']"/>
            <entry key="somethingElse" value="headers['MY_FIELDC']"/>
        </map>
    </property>
</bean>

请参阅本部分 在 spring 参考文档中了解更多详细信息.

Please see this section in spring reference documentation for more details.

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