如何为JdbcPollingChannelAdapter的更新参数设置非缓存SqlParameterSource

Great question! I’ve run into this exact asymmetry before when working with JdbcPollingChannelAdapter—it’s frustrating that select parameters let you pass a direct, non-cached SqlParameterSource, but updates are tied to a factory. Let’s break down the solution.

The Core Issue #

By default, the ExpressionEvaluatingSqlParameterSourceFactory (the common factory for update parameters) caches the SqlParameterSource instance it creates. This works for static parameters, but if you need dynamic, per-poll update parameters (like you do with your non-cached select parameters), you need to disable this caching behavior.

Solution 1: Disable Caching in the Default Factory #

The simplest fix is to configure the standard ExpressionEvaluatingSqlParameterSourceFactory to not cache its parameter sources. This makes it behave just like calling createParameterSourceNoCache() for your select parameters.

Java Configuration Example

// Create the factory and disable caching
ExpressionEvaluatingSqlParameterSourceFactory updateParamFactory = new ExpressionEvaluatingSqlParameterSourceFactory();
updateParamFactory.setCacheEnabled(false); // This is the key line

// Configure your adapter
JdbcPollingChannelAdapter adapter = new JdbcPollingChannelAdapter(dataSource, "SELECT id, data FROM my_table WHERE status = :status");
adapter.setUpdateSql("UPDATE my_table SET status = 'PROCESSED' WHERE id = :id");

// Set the non-caching factory for updates
adapter.setUpdateSqlParameterSourceFactory(updateParamFactory);

XML Configuration Example

<int-jdbc:inbound-channel-adapter 
    id="jdbcPoller" 
    query="SELECT id, data FROM my_table WHERE status = :status" 
    update="UPDATE my_table SET status = 'PROCESSED' WHERE id = :id" 
    data-source="dataSource">

    <!-- Disable caching for update parameters -->
    <int-jdbc:update-sql-parameter-source-factory>
        <int-jdbc:expression-evaluating-sql-parameter-source-factory cache-enabled="false"/>
    </int-jdbc:update-sql-parameter-source-factory>

</int-jdbc:inbound-channel-adapter>

When cacheEnabled is set to false, the factory will create a new SqlParameterSource instance every time the adapter runs an update, which matches the non-cached behavior you’re using for your select parameters.

Solution 2: Custom Factory for Full Control #

If you need even more flexibility (like dynamically generating parameters based on the poll results or other context), you can create a custom SqlParameterSourceFactory that always returns a fresh instance:

public class DynamicUpdateParamFactory implements SqlParameterSourceFactory {

    @Override
    public SqlParameterSource createParameterSource(Object input) {
        // input will be the result of the select query (if using a row mapper, it's the mapped object)
        MyRecord record = (MyRecord) input;
        
        // Create a new parameter source every time, with dynamic values
        return new MapSqlParameterSource()
                .addValue("id", record.getId())
                .addValue("processedTimestamp", LocalDateTime.now());
    }
}

Then attach it to your adapter:

adapter.setUpdateSqlParameterSourceFactory(new DynamicUpdateParamFactory());

This approach gives you full control over how update parameters are generated, with zero caching by default.

Wrap-Up #

For most cases, disabling caching on the standard ExpressionEvaluatingSqlParameterSourceFactory is the quickest and cleanest solution. It aligns the update parameter behavior with your non-cached select parameters, ensuring you get fresh values on every poll.

内容的提问来源于stack exchange，提问作者Curtis Olson