Spring JdbcTemplate Querying Examples
Here are a few examples to show you how to use Spring JdbcTemplate
to query or extract data from database.
Technologies used :
- Spring Boot 2.1.2.RELEASE
- Spring JDBC 5.1.4.RELEASE
- Maven 3
- Java 8
In Short:
jdbcTemplate.queryForObject
for single row or valuejdbcTemplate.query
for multiple rows or list
The article is updated from Spring core 2.5.x to Spring Boot 2.1.x
P.S You may also interested in this Spring Boot JDBC Examples
1. Query for Single Row
In Spring, we can use jdbcTemplate.queryForObject()
to query a single row record from database, and convert the row into an object via row mapper.
1.1 Custom RowMapper
import org.springframework.jdbc.core.RowMapper;
import java.sql.ResultSet;
import java.sql.SQLException;
public class CustomerRowMapper implements RowMapper<Customer> {
@Override
public Customer mapRow(ResultSet rs, int rowNum) throws SQLException {
Customer customer = new Customer();
customer.setID(rs.getLong("ID"));
customer.setName(rs.getString("NAME"));
customer.setAge(rs.getInt("AGE"));
customer.setCreatedDate(rs.getTimestamp("created_date").toLocalDateTime());
return customer;
}
}
import org.springframework.jdbc.core.JdbcTemplate;
@Autowired
private JdbcTemplate jdbcTemplate;
public Customer findByCustomerId(Long id) {
String sql = "SELECT * FROM CUSTOMER WHERE ID = ?";
return jdbcTemplate.queryForObject(sql, new Object[]{id}, new CustomerRowMapper());
}
1.2 Spring BeanPropertyRowMapper
, this class saves you a lot of time for the mapping.
import org.springframework.jdbc.core.BeanPropertyRowMapper;
public Customer findByCustomerId2(Long id) {
String sql = "SELECT * FROM CUSTOMER WHERE ID = ?";
return (Customer) jdbcTemplate.queryForObject(
sql,
new Object[]{id},
new BeanPropertyRowMapper(Customer.class));
}
1.3 In Java 8, we can map it directly:
public Customer findByCustomerId3(Long id) {
String sql = "SELECT * FROM CUSTOMER WHERE ID = ?";
return jdbcTemplate.queryForObject(sql, new Object[]{id}, (rs, rowNum) ->
new Customer(
rs.getLong("id"),
rs.getString("name"),
rs.getInt("age"),
rs.getTimestamp("created_date").toLocalDateTime()
));
}
2. Query for Multiple Rows
For multiple rows, we use jdbcTemplate.query()
2.1 Custom RowMapper
public List<Customer> findAll() {
String sql = "SELECT * FROM CUSTOMER";
List<Customer> customers = jdbcTemplate.query(
sql,
new CustomerRowMapper());
return customers;
}
2.2 BeanPropertyRowMapper
public List<Customer> findAll() {
String sql = "SELECT * FROM CUSTOMER";
List<Customer> customers = jdbcTemplate.query(
sql,
new BeanPropertyRowMapper(Customer.class));
return customers;
}
2.3 Java 8
public List<Customer> findAll() {
String sql = "SELECT * FROM CUSTOMER";
return jdbcTemplate.query(
sql,
(rs, rowNum) ->
new Customer(
rs.getLong("id"),
rs.getString("name"),
rs.getInt("age"),
rs.getTimestamp("created_date").toLocalDateTime()
)
);
}
2.4 jdbcTemplate.queryForList
, it works, but not recommend, the mapping in Map
may not same as the object, need casting.
public List<Customer> findAll() {
String sql = "SELECT * FROM CUSTOMER";
List<Customer> customers = new ArrayList<>();
List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);
for (Map row : rows) {
Customer obj = new Customer();
obj.setID(((Integer) row.get("ID")).longValue());
obj.setName((String) row.get("NAME"));
// Spring returns BigDecimal, need convert
obj.setAge(((BigDecimal) row.get("AGE")).intValue());
obj.setCreatedDate(((Timestamp) row.get("CREATED_DATE")).toLocalDateTime());
customers.add(obj);
}
return customers;
}
3. Query for a Single Value
It’s same like query a single row from database, uses jdbcTemplate.queryForObject()
3.1 Single column name
public String findCustomerNameById(Long id) {
String sql = "SELECT NAME FROM CUSTOMER WHERE ID = ?";
return jdbcTemplate.queryForObject(
sql, new Object[]{id}, String.class);
}
3.2 Count
public int count() {
String sql = "SELECT COUNT(*) FROM CUSTOMER";
// queryForInt() is Deprecated
// https://www.mkyong.com/spring/jdbctemplate-queryforint-is-deprecated/
//int total = jdbcTemplate.queryForInt(sql);
return jdbcTemplate.queryForObject(sql, Integer.class);
}
4. Test
Run a Spring Boot CommandLineRunner
application, create tables and test the APIs.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!-- in-memory database -->
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
package com.mkyong;
import com.mkyong.customer.Customer;
import com.mkyong.customer.CustomerRepository;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.jdbc.core.JdbcTemplate;
import java.math.BigDecimal;
import java.util.Arrays;
import java.util.List;
@SpringBootApplication
public class StartApplication implements CommandLineRunner {
private static final Logger log = LoggerFactory.getLogger(StartApplication.class);
@Autowired
JdbcTemplate jdbcTemplate;
@Autowired
CustomerRepository customerRepository;
public static void main(String[] args) {
SpringApplication.run(StartApplication.class, args);
}
@Override
public void run(String... args) {
log.info("StartApplication...");
startCustomerApp();
}
// Tested with H2 database
void startCustomerApp() {
jdbcTemplate.execute("DROP TABLE customer IF EXISTS");
jdbcTemplate.execute("CREATE TABLE customer(" +
"id SERIAL, name VARCHAR(255), age NUMERIC(2), created_date timestamp)");
List<Customer> list = Arrays.asList(
new Customer("Customer A", 19),
new Customer("Customer B", 20),
new Customer("Customer C", 21),
new Customer("Customer D", 22)
);
list.forEach(x -> {
log.info("Saving...{}", x.getName());
customerRepository.save(x);
});
log.info("[FIND_BY_ID]");
log.info("{}", customerRepository.findByCustomerId(1L));
log.info("{}", customerRepository.findByCustomerId2(2L));
log.info("{}", customerRepository.findByCustomerId3(3L));
log.info("[FIND_ALL]");
log.info("{}", customerRepository.findAll());
log.info("{}", customerRepository.findAll2());
log.info("{}", customerRepository.findAll3());
log.info("{}", customerRepository.findAll4());
log.info("[FIND_NAME_BY_ID]");
log.info("{}", customerRepository.findCustomerNameById(4L));
log.info("[COUNT]");
log.info("{}", customerRepository.count());
}
}
Output
INFO com.mkyong.StartApplication - Saving...Customer A
INFO com.mkyong.StartApplication - Saving...Customer B
INFO com.mkyong.StartApplication - Saving...Customer C
INFO com.mkyong.StartApplication - Saving...Customer D
INFO com.mkyong.StartApplication - [FIND_BY_ID]
INFO com.mkyong.StartApplication - Customer{ID=1, name='Customer A', age=19, createdDate=2019-08-01T15:48:45.950848}
INFO com.mkyong.StartApplication - Customer{ID=2, name='Customer B', age=20, createdDate=2019-08-01T15:48:45.961819}
INFO com.mkyong.StartApplication - Customer{ID=3, name='Customer C', age=21, createdDate=2019-08-01T15:48:45.961819}
INFO com.mkyong.StartApplication - [FIND_ALL]
INFO com.mkyong.StartApplication - [
Customer{ID=1, name='Customer A', age=19, createdDate=2019-08-01T15:48:45.950848},
Customer{ID=2, name='Customer B', age=20, createdDate=2019-08-01T15:48:45.961819},
Customer{ID=3, name='Customer C', age=21, createdDate=2019-08-01T15:48:45.961819},
Customer{ID=4, name='Customer D', age=22, createdDate=2019-08-01T15:48:45.961819}
]
//...omitted, duplicate code
INFO com.mkyong.StartApplication - [FIND_NAME_BY_ID]
INFO com.mkyong.StartApplication - Customer D
INFO com.mkyong.StartApplication - [COUNT]
INFO com.mkyong.StartApplication - 4
Does any body know how to map 1 to Any using JDBCTeamplate?.. Need to map something like person with multiple cars and produce Json.
Can you explain JDBC template with DTO?
Hey I have a problem with retrieving Timestamp values from databse using jdbc template. Please put an example of that here
Hey do you know which form of jdbctemplate.query will not throw any exception when no rows are fetched from DB??
Spring MVC DataSource
Data base
Model
DAO
Dao Imp
Controller
fuente: Spring Recipes A Problem-Solution Approach
Awesome one but it would be gud if you could provide a link for what is tag and what is @RequestMapping annotation mean and what it does.
Because all these tutorials are related to Spring Core but not to MVC but the tags that you have mentioned are related to MVC here.
Tag that i am refering to is <mvc:annotation-driven /> in my above comment
First: thanks, very useful material!
When using “RowCallbackHandler”, I found that first record is already “consumed”, I had to use a “do { .. }while (resultSet.next());” loop in order to iterate over all data – funny thing
I am trying to use org.springframework.jdbc.core.JdbcTemplate . Stored procedure returns 2 different result sets. How to retrieve those? For 1 result set I am using jdbcTemplate.query(). When I tried to create 2 different methods based on 2 different result sets, I am still getting 1st result set.
Thanks in advance!!
Hi,
I have millions of records in database, and I need to write the in csv file. Now when I do select * from , I get exception Exception in thread “main” java.lang.OutOfMemoryError: Java heap space. Could you please suggest some way to read this data in chunk and write to the file.
can you tall me where you declare getJdbcTemplate() mathode in class and how to create JdbcTemplateObject
Hi. Thank you for the post. I have a question. If the resultset is too huge, how deal with it? A can’t retrieve the list without get a “Handler dispatch failed; nested exception is java.lang.OutOfMemoryError: Java heap space” Thank you in advance.
Do you have any experience using mybatis-spring framework for persistence ? I am struggling to get null pointer eception resolved due to dependency injection not working
I have a table just with one colomn n one row.. if i want to update that record.. u use update method n set query.. now i want to fetch that single record. I dont have any value to pass as an input. I write sql query as select * from mytable.. n it should give me that single record. Please help me in choosing suitable method.. it will be helpful
You can use ‘queryForList’ and do list.get(0) to get the record.
We have a environment where we have a web server and a application server. We can connect to DB only via application server where as web server is exposed to the users for using the system.
We have deployed the application on both the server but the problem we are facing is that, How we can execute spring JDBC template from the application server via web server ?
Ex: If user has filled the information in the from and now trying to save the data on web server (but we don’t have connectivity from web server) data should be saved via application server.
I hope I am able to explain my problem.
I must say very simple and concise Explanation.
We understand the contrast of using RowMapper and another way of doing the same thing.
Hello,
I am looking for something which can written
Map<Long, List
In my requirement I want to all the list of employee as per the department id from the Employee table.
Thanks in advance.
Which approach to follow if i have to select million records from database and write to a flat file
how can i write the Junit for the CustomerRowMapper class which is mentioned above
Thank you for good information.
You made mistake in JdbcTemplateApp.java file.
Here is the code snippet:
List customerAs = customerDAO.findAll();
for(Customer cust: customerAs){
System.out.println(“Customer As : ” + customerAs);
}
List customerBs = customerDAO.findAll2();
for(Customer cust: customerBs){
System.out.println(“Customer Bs : ” + customerBs);
}
Problem:
List of customers will be printed multiple times(eqaul to total number of customers).
Solution:
There should be “cust” to printed instead of “customerAs” or “customerBs”.
OR
Simply remove the for loops.
I am trying to set the Parent List in a ParameterizedRowMapper how is this written or approached. I have two Objects one for parent and one for children however children contains a ListThe parents for each child are stored in a separate table in the database and the mapping is 1 – many.
The select for the records for the parents will be done in a separate ResultSet. Will the mapping have to be done separately (separate ParameterizedRowMapper), if so how will i have to write the ParameterizedRowMapper this is the major concern how ParameterizedRowMapper is written to accommodate a list items.
public static class ChildrenMapper implements ParameterizedRowMapper{
public Children mapRow(ResultSet rs, int rowNum) throws SQLException {
Children child = new Children();
child.setFirstName(rs.getString(“firstName”));
child.setLastName(rs.getString(“lastName”));
//a child can have many Parents or gaurdians
child.setParent(List);
return child;
}
}
Interesting…it keeps removing the generics from the declaration from what is being posted.
List<Map > rows = jdbcTemplate.queryForList(sql);
I think there is an error in the findAll (Manually) method. Here is how I think ‘rows’ should be declared.
List<Map > rows = jdbcTemplate.queryForList(sql);
Nice thx
To map multiple rows you should take a look at the
interface.
Hi, I am getting problem while reading the Resultset of queryForList
jdbcQuery=”SELECT sp.rollNo rollno, sa.studentName stname, c.shortCode AS shortcode,CONCAT(SUM(sa.present) , ‘/’,COUNT(sa.present),’ (‘, ROUND(SUM(sa.present)*100/COUNT(sa.present),2),’%)’) AS percentage FROM studentattendance sa,studentprofile sp,course c,lecture l WHERE sa.studentId=sp.id AND c.type=’Theory’ AND sp.division_id=1 AND l.startDate >= ‘2012-01-01’ AND l.endDate <= '2012-02-16' AND sa.lectureId=l.id AND l.course_id=c.id GROUP BY sa.studentName,c.name"
geting object address
List<Map> resultSetList = jdbcTemplate.queryForList(jdbcQuery);
Iterator<Map> qdataMapItr = resultSetList.iterator();
String checkString=””;
Map courseAttendMap=null;
while(qdataItr.hasNext())
{
Map mapobj = qdataItr.next();
System.out.println(” shortCode:”+mapobj.get(“shortcode”)+ ” percentage:”+mapobj.get(“percentage”));
}
OUTPUT:
shortCode:APM(TH) percentage:[B@3435
Why it is so? i dont understand. I am able read shortcode,rollno,stname but while getting percentage its giving Object address…
please help!!!!!!!!!!!!!!!!!!
on executing the above query on query browser giving following output. I am using mysql.
rollno stname shortcode percentage
21A01 ADHIKARI NILESH MADHUKAR APM(TH) 8/14 (57.14%)
21A01 ADHIKARI NILESH MADHUKAR CT(TH) 13/16 (81.25%)
21A01 ADHIKARI NILESH MADHUKAR FM-1(TH) 20/23 (86.96%)
21A01 ADHIKARI NILESH MADHUKAR SA-1(TH) 23/27 (85.19%)
21A01 ADHIKARI NILESH MADHUKAR SURVEYING(TH) 12/12 (100.00%)
21A02 AHER AMIT ANNASAHEB BP(TH) 9/14 (64.29%)
please help!!!
If my query is like :
String sql = “SELECT * FROM CUSTOMER where name in (‘abc’,’xyz’…)”;
what should be the code ?
You can use NamedParameterJdbc template to achieve this.
NamedParameterJdbcTemplate namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(jdbcTemplate);
MapSqlParameterSource parameters = new MapSqlParameterSource();
parameters.addValue(“names”, Arrays.asList(“abc”, “xyz”));
List objList = namedParameterJdbcTemplate.query(“select * from foo where name in (:names)”,
parameters,
new urobjRowMapper()
);
2.1 Map it manually shows a nice manual way
Alternative could be like this below and get a list of customers. Although we should use query instead of queryForObject
List getJdbcTemplate().query(
sql, new Object[] { custId }, new CustomerRowMapper());
Awesome tut mate…well done …saved my life eh …ta
Nice one. Thanks:)
you welcom