The NamedParameterJdbcTemplate class helps you specify the named parameters instead of classic placeholder(‘?’) argument. Named parameters improves readability and are easier to maintain.
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The NamedParameterJdbcTemplate provide better approach than JdbcTemplate ,where multiple parameters are in use for an SQL statement. It eliminated need of traditional JDBC “?” and provide named parameters. It is easy to use and provide better documentation. It functionality is similar to JdbcTemplate except it incorporate named parameters instead of “?” placeholder.
In JdbcTemplate, SQL parameters are represented by a special placeholder “?” symbol and bind it by position. The problem is whenever the order of parameter is changed, you have to change the parameters bindings as well, it’s error prone and cumbersome to maintain it.
In additional, the named parameters are only support in SimpleJdbcTemplate and NamedParameterJdbcTemplate.
EmpDao.java
package com.dineshonjava.sdnext.dao;
import java.util.List;
import com.dineshonjava.sdnext.domain.Employee;
/**
* @author Dinesh Rajput
*
*/
public interface EmpDao {
/**
* This is the method to be used to create
* a record in the Employee table.
*/
void create(String name, Integer age, Long salary);
/**
* This is the method to be used to list down
* a record from the Employee table corresponding
* to a passed Employee id.
*/
Employee getEmployee(Integer empid);
/**
* This is the method to be used to list down
* all the records from the Employee table.
*/
List listEmployees();
/**
* This is the method to be used to delete
* a record from the Employee table corresponding
* to a passed Employee id.
*/
void delete(Integer empid);
/**
* This is the method to be used to update
* a record into the Employee table.
*/
void update(Integer empid, Integer age);
}
EmployeeDaoImpl.java
package com.dineshonjava.sdnext.dao.impl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
import org.springframework.stereotype.Component;
import com.dineshonjava.sdnext.dao.EmpDao;
import com.dineshonjava.sdnext.domain.Employee;
import com.dineshonjava.sdnext.jdbc.utils.EmployeeMapper;
/**
* @author Dinesh Rajput
*
*/
@Component
public class EmployeeDaoImpl implements EmpDao {
@Autowired
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;
/**
* @param namedParameterJdbcTemplate the namedParameterJdbcTemplate to set
*/
public void setNamedParameterJdbcTemplate(NamedParameterJdbcTemplate namedParameterJdbcTemplate) {
this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;
}
@Override
public void create(String name, Integer age, Long salary) {
String SQL = "INSERT INTO Employee (name, age, salary) VALUES (:name, :age, :salary)";
Map namedParameters = new HashMap();
namedParameters.put("name", name);
namedParameters.put("age", age);
namedParameters.put("salary", salary);
namedParameterJdbcTemplate.update(SQL, namedParameters);
System.out.println("Created Record Name = " + name + " Age = " + age+ " Salary = " + salary);
}
@Override
public Employee getEmployee(Integer empid) {
String SQL = "SELECT * FROM Employee WHERE empid = :empid";
SqlParameterSource namedParameters = new MapSqlParameterSource("empid", Integer.valueOf(empid));
Employee employee = (Employee) namedParameterJdbcTemplate.queryForObject(SQL, namedParameters, new EmployeeMapper());
return employee;
}
@Override
public List listEmployees() {
String SQL = "SELECT * FROM Employee";
List employees = (List) namedParameterJdbcTemplate.query(SQL, new EmployeeMapper());
return employees;
}
@Override
public void delete(Integer empid) {
String SQL = "DELETE FROM Employee WHERE empid = :empid";
SqlParameterSource namedParameters = new MapSqlParameterSource("empid", Integer.valueOf(empid));
namedParameterJdbcTemplate.update(SQL, namedParameters);
System.out.println("Deleted Record with EMPID = " + empid );
}
@Override
public void update(Integer empid, Integer age) {
String SQL = "UPDATE Employee SET age = :age WHERE empid = :empid";
SqlParameterSource namedParameters = new MapSqlParameterSource();
namedParameters.addValue("age", age);
namedParameters.addValue("empid", empid);
namedParameterJdbcTemplate.update(SQL, namedParameters);
System.out.println("Updated Record with EMPID = " + empid );
}
}
EmployeeMapper.java
package com.dineshonjava.sdnext.jdbc.utils;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;
import com.dineshonjava.sdnext.domain.Employee;
/**
* @author Dinesh Rajput
*
*/
public class EmployeeMapper implements RowMapper {
public Employee mapRow(ResultSet rs, int rowNum) throws SQLException {
Employee employee = new Employee();
employee.setEmpid(rs.getInt("empid"));
employee.setName(rs.getString("name"));
employee.setAge(rs.getInt("age"));
employee.setSalary(rs.getLong("salary"));
return employee;
}
}
Spring.xml
<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:security="http://www.springframework.org/schema/security" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-2.0.4.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
<context:annotation-config></context:annotation-config>
<context:component-scan base-package="com.dineshonjava.sdnext.dao.impl">
</context:component-scan>
<bean class="org.apache.commons.dbcp.BasicDataSource" id="dataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/DAVDB"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>
<property name="initialSize" value="2"></property>
<property name="maxActive" value="5"></property>
</bean>
<bean class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate" id="namedParameterJdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
</beans>
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