Connect MySQL to Spring application

Question

I want to use MySQL database rather than using runtime database like hsqldb. I have cloned this repository and it is using hsqldb as its database.

As I want to learn how to use relational database with rest based spring application. So I have made following changes to pom.xml: changed pom.xml:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.springsource.restbucks</groupId>
    <artifactId>restbucks</artifactId>
    <packaging>war</packaging>
    <version>1.0.0.BUILD-SNAPSHOT</version>
    <name>Spring RESTBucks</name>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.5.RELEASE</version>
    </parent>

    <properties>
        <spring-data-releasetrain.version>Evans-RC1</spring-data-releasetrain.version>
        <tomcat.version>8.0.9</tomcat.version>
    </properties>

    <dependencies>

        <!-- Spring Data REST -->

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.hibernate</groupId>
                    <artifactId>hibernate-entitymanager</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

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

        <!-- JDK 8 DateTime support for Hibernate -->

        <dependency>
            <groupId>org.jadira.usertype</groupId>
            <artifactId>usertype.extended</artifactId>
            <version>3.2.0.GA</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
        </dependency>

        <!-- Database >

        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <scope>runtime</scope>
        </dependency -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- Misc -->

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx-events</artifactId>
            <version>1.0.0.BUILD-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.14.4</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>com.jayway.jsonpath</groupId>
            <artifactId>json-path</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-libs-snapshot</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>spring-libs-snapshot</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>

and in application.properties (spring-restbucks/src/main/resources/application.properties), I have made following changes:

# JPA
spring.jpa.show-sql=true

server.port=8080

spring.datasource.url=jdbc:mysql://localhost/restBucks

spring.datasource.driverClassName=com.mysql.jdbc.Driver

spring.datasource.username=root

spring.datasource.password=

but I am facing about 15 errors like:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'orderInitializer' defined in file [/home/jimish/projects/spring_projects/spring/spring-restbucks/target/classes/org/springsource/restbucks/order/OrderInitializer.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springsource.restbucks.order.OrderInitializer]: Constructor threw exception; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet

So if anyone can suggest path for how to connect mysql to spring application that would be great. Thanks.

Answer 1

Include only the following configuration in your application.properties in classpath and it will work like a charm:

 spring.datasource.url=jdbc:mysql://localhost/jpa_example
 spring.datasource.username=root
 spring.datasource.driver-class-name=com.mysql.jdbc.Driver
 spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

This "spring.jpa.database-platform" specify which database you are going to use. It may be postgress, MySQL etc. According to that you need to specify it.

Answer 2

Expounding on @M. Deinum's comment... You need to specify the JPA configuration information as the Spring RestBucks App is using Spring Data JPA.

Adding standard JPA properties and specifying the database-platform (Common Application Properties) should get your JPA connection working.

spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

# Enable spring data repos 
spring.data.jpa.repositories.enabled=true

# Replace with your connection string
spring.datasource.url=jdbc:mysql://localhost:3306/restbucks

# Replace with your credentials
spring.datasource.username=sa
spring.datasource.password=

spring.datasource.driverClassName=com.mysql.jdbc.Driver

Answer 3

Add bellow properties in your application.properties file:

# Use one of create/update/create-update    
spring.jpa.hibernate.ddl-auto=update  
spring.datasource.url=jdbc:mysql://localhost:3306/db?createDatabaseIfNotExist=true   
spring.datasource.username=root  //your db user name  
spring.datasource.password=root  //your db user password 
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform=org.hibernate.dialect.MySQL8Dialect  
#If your MySql version 5 then use MySQL5Dialect


# Enable spring data repos
spring.data.jpa.repositories.enabled=true
spring.jpa.show-sql=true
spring.jpa.database=mysql

Answer 4

Add MySQL Connector/J to classpath:

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>6.0.5</version>
</dependency>

This is an example of file application.properties inside Spring-based application:

datasource.mine.poolSize=30

spring.datasource.url=jdbc:mysql://127.0.0.1/vy?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driverClassName=com.mysql.jdbc.Driver

spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update