- The NamedParameterJdbcTemplate is a part of the Spring Framework’s JDBC support and is an extension of the standard JdbcTemplate. It provides a more convenient and readable way to work with JDBC by allowing you to use named parameters in SQL queries instead of positional placeholders.
- This can make your SQL queries more self-explanatory and less error-prone, especially when dealing with queries that have a large number of parameters.
Create a NamedParameterJdbcTemplate:
- You need to create an instance of NamedParameterJdbcTemplate. Typically, you’ll pass in a DataSource or a JdbcTemplate as a parameter to its constructor.
import org.springframework.jdbc.core.
namedparam.NamedParameterJdbcTemplate;
// Assuming you have a
JdbcTemplate or DataSource
instance
NamedParameterJdbcTemplate
namedParameterJdbcTemplate
= new NamedParameterJdbcTemplate
(jdbcTemplate);
- Spring provides another way to insert data by named parameter. In such way, we use names instead of ?(question mark). So it is better to remember the data for the column.
Write SQL Queries with Named Parameters:
- In your SQL queries, you can use named parameters preceded by a colon (e.g., :paramName) instead of the traditional question mark placeholders.
String sql = "SELECT * FROM
my_table WHERE column1 =
:value1 AND column2 = :value2";
Create a Map of Parameters:
- You’ll create a Map where the keys are the parameter names (without the colon) and the values are the actual parameter values.
Map<String, Object> params =
new HashMap<>();
params.put("value1", someValue1);
params.put("value2", someValue2);
Execute the Query:
- You can then execute the query using NamedParameterJdbcTemplate by passing in the SQL query and the parameter map as arguments.
List<MyObject> result =
namedParameterJdbcTemplate
.query(sql, params, new MyRowMapper());
- The NamedParameterJdbcTemplate will replace the named parameters in the SQL query with the corresponding values from the parameter map, and then it will execute the query using a regular JdbcTemplate under the hood.
import org.springframework.jdbc
.core.namedparam
.NamedParameterJdbcTemplate;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class MyService {
private NamedParameterJdbcTemplate
namedParameterJdbcTemplate;
public MyService(NamedParameterJdbcTemplate
namedParameterJdbcTemplate) {
this.namedParameterJdbcTemplate
=namedParameterJdbcTemplate;
}
public List<MyObject> getMyObjectsByValues
(String value1, String value2) {
String sql = "SELECT
* FROM my_table WHERE column1 = :value1
AND column2 = :value2";
Map<String, Object> params =
new HashMap<>();
params.put("value1", value1);
params.put("value2", value2);
return namedParameterJdbcTemplate.query
(sql, params, new MyRowMapper());
}
}
- Using NamedParameterJdbcTemplate can make your code more readable, maintainable, and less error-prone when working with complex SQL queries that involve multiple parameters. It’s a valuable tool for JDBC-based data access in Spring applications.
