Spring + JdbcTemplate + JdbcDaoSupport examples

如何传递参数；返回结果如何转换为model;

In Spring JDBC development, you can use

JdbcTemplate

and

JdbcDaoSupport

classes to simplify the overall database operation processes.

In this tutorial, we will reuse the last Spring + JDBC example, to see the different between a before (No

JdbcTemplate

support) and after (With

JdbcTemplate

support) example.

1. Example Without

JdbcTemplate

Witout

JdbcTemplate

, you have to create many redundant codes (create connection , close connection , handle exception) in all the DAO database operation methods – insert, update and delete. It just not efficient, ugly, error prone and tedious.

private DataSource dataSource;

public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}

public void insert(Customer customer){

String sql = "INSERT INTO CUSTOMER " +
"(CUST_ID, NAME, AGE) VALUES (?, ?, ?)";
Connection conn = null;

try {
conn = dataSource.getConnection();
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1, customer.getCustId());
ps.setString(2, customer.getName());
ps.setInt(3, customer.getAge());
ps.executeUpdate();
ps.close();

} catch (SQLException e) {
throw new RuntimeException(e);

} finally {
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {}
}
}
}

2. Example With

JdbcTemplate

With

JdbcTemplate

, you save a lot of typing on the redundant codes, becuase

JdbcTemplate

will handle it automatically.

private DataSource dataSource;
private JdbcTemplate jdbcTemplate;

public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}

public void insert(Customer customer){

String sql = "INSERT INTO CUSTOMER " +
"(CUST_ID, NAME, AGE) VALUES (?, ?, ?)";

jdbcTemplate = new JdbcTemplate(dataSource);

jdbcTemplate.update(sql, new Object[] { customer.getCustId(),
customer.getName(),customer.getAge()
});

}

See the different?

3. Example With

JdbcDaoSupport

By extended the

JdbcDaoSupport

, set the

datasource

and

JdbcTemplate

in your class is no longer required, you just need to inject the correct

datasource

into

JdbcCustomerDAO

. And you can get the

JdbcTemplate

by using a

getJdbcTemplate()

method.

public class JdbcCustomerDAO extends JdbcDaoSupport implements CustomerDAO
{
//no need to set datasource here
public void insert(Customer customer){

String sql = "INSERT INTO CUSTOMER " +
"(CUST_ID, NAME, AGE) VALUES (?, ?, ?)";

getJdbcTemplate().update(sql, new Object[] { customer.getCustId(),
customer.getName(),customer.getAge()
});

}

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> 
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/mkyongjava" />
<property name="username" value="root" />
<property name="password" value="password" />
</bean>

</beans>

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> 
<bean id="customerDAO" class="com.mkyong.customer.dao.impl.JdbcCustomerDAO">
<property name="dataSource" ref="dataSource" />
</bean>

</beans>

Note

In Spring JDBC development, it’s always recommended to use

JdbcTemplate

and

JdbcDaoSupport

, instead of coding JDBC code yourself.