Friday, 13 September 2019

Spring boot: Configure Data Source programmatically


You can configure data source programmatically using below snippet.

@Bean
public DataSource getDataSource() {
 DataSourceBuilder dataSourceBuilder = DataSourceBuilder.create();
 dataSourceBuilder.driverClassName("org.h2.Driver");
 dataSourceBuilder.url("jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;");
 dataSourceBuilder.username("krishna");
 dataSourceBuilder.password("password123");
 return dataSourceBuilder.build();
}

Find the below working application.


App.java
package com.sample.app;

import java.util.Arrays;
import java.util.List;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

import com.sample.app.entity.Employee;
import com.sample.app.repository.EmployeeRepository;

@SpringBootApplication
public class App {

 public static void main(String[] args) {
  SpringApplication.run(App.class);
 }

 @Bean
 public CommandLineRunner demo(EmployeeRepository employeeRepository) {
  return (args) -> {
   Employee emp1 = new Employee();
   emp1.setFirstName("Hari Krishna");
   emp1.setLastName("Ponnam");
   
   Employee emp2 = new Employee();
   emp2.setFirstName("Krishna");
   emp2.setLastName("Gurram");

   List<Employee> emps = Arrays.asList(emp1, emp2);
   
   employeeRepository.saveAll(emps);
   
   for(Employee emp: emps) {
    System.out.println(emp);
   }
   
  };
 }

}


DataSourceConfig.java
package com.sample.app.config;

import javax.sql.DataSource;

import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class DataSourceConfig {
 @Bean
 public DataSource getDataSource() {
  DataSourceBuilder dataSourceBuilder = DataSourceBuilder.create();
  dataSourceBuilder.driverClassName("org.h2.Driver");
  dataSourceBuilder.url("jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;");
  dataSourceBuilder.username("krishna");
  dataSourceBuilder.password("password123");
  return dataSourceBuilder.build();
 }
}


Employee.java
package com.sample.app.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "employee")
public class Employee {
 @Id
 @GeneratedValue
 @Column(name = "employee_id")
 private int id;

 @Column(name = "first_name")
 private String firstName;

 @Column(name = "last_name")
 private String lastName;

 public int getId() {
  return id;
 }

 public void setId(int id) {
  this.id = id;
 }

 public String getFirstName() {
  return firstName;
 }

 public void setFirstName(String firstName) {
  this.firstName = firstName;
 }

 public String getLastName() {
  return lastName;
 }

 public void setLastName(String lastName) {
  this.lastName = lastName;
 }

 @Override
 public String toString() {
  StringBuilder builder = new StringBuilder();
  builder.append("Employee [id=").append(id).append(", firstName=").append(firstName).append(", lastName=")
    .append(lastName).append("]");
  return builder.toString();
 }

}


EmployeeRepository.java
package com.sample.app.repository;

import org.springframework.data.jpa.repository.JpaRepository;

import com.sample.app.entity.Employee;

public interface EmployeeRepository extends JpaRepository<Employee, Integer> {

}


application.properties
logging.level.root=WARN
logging.level.org.hibernate=ERROR

## JPA specific properties
# Creates the schema, destroying previous data.
spring.jpa.hibernate.ddl-auto=create

spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

## Database connection pooling properties
# Number of ms to wait before throwing an exception if no connection is available.
spring.datasource.max-wait=10000

# Maximum number of active connections that can be allocated from this pool at the same time.
spring.datasource.tomcat.max-active=10
spring.datasource.tomcat.max-idle=5
spring.datasource.tomcat.min-idle=3

spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true


pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>springbootMisc</groupId>
 <artifactId>springbootMisc</artifactId>
 <version>1</version>

 <parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.1.6.RELEASE</version>
 </parent>

 <packaging>jar</packaging>

 <dependencies>

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-jpa</artifactId>
  </dependency>


  <dependency>
   <groupId>com.h2database</groupId>
   <artifactId>h2</artifactId>
  </dependency>
 </dependencies>

</project>


Total project structure looks like below.


Run App.java, you can see below messages in console.
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.6.RELEASE)

Hibernate: 
    
    drop table employee if exists
Hibernate: 
    
    drop sequence if exists hibernate_sequence
Hibernate: create sequence hibernate_sequence start with 1 increment by 1
Hibernate: 
    
    create table employee (
       employee_id integer not null,
        first_name varchar(255),
        last_name varchar(255),
        primary key (employee_id)
    )
Hibernate: 
    call next value for hibernate_sequence
Hibernate: 
    call next value for hibernate_sequence
Hibernate: 
    insert 
    into
        employee
        (first_name, last_name, employee_id) 
    values
        (?, ?, ?)
Hibernate: 
    insert 
    into
        employee
        (first_name, last_name, employee_id) 
    values
        (?, ?, ?)
Employee [id=1, firstName=Hari Krishna, lastName=Ponnam]
Employee [id=2, firstName=Krishna, lastName=Gurram]

You can download complete working application from this link.


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