Spring Boot | Database Access | Using an External Database

Using an External Database

MySQL Table

Use a local MySQL database.

test_table

id	value
1	hoge
2	fuga
3	piyo

Writing the Code

build.gradle

dependencies {
    compile 'org.springframework.boot:spring-boot-starter-jdbc'
    compile 'mysql:mysql-connector-java:5.1.35'
}

application.properties

spring.datasource.url=jdbc:mysql://localhost/test
spring.datasource.username=test
spring.datasource.password=test
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

src/main/java/sample/springboot/Main.java

package sample.springboot;

import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;

@SpringBootApplication
public class Main {

    public static void main(String[] args) {
        try (ConfigurableApplicationContext ctx = SpringApplication.run(Main.class, args)) {
            Main m = ctx.getBean(Main.class);
            m.method();
        }
    }

    @Autowired
    private JdbcTemplate jdbc;

    public void method() {
        List<Map<String, Object>> list = this.jdbc.queryForList("SELECT * FROM TEST_TABLE");
        list.forEach(System.out::println);
    }
}

Result

{id=1, value=hoge}
{id=2, value=fuga}
{id=3, value=piyo}

Add connection settings to application.properties to connect to an external database.