Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured

Question

I am working on a Spring Boot Batch example with MongoDB and I have already started the mongod server.

When I launch my application, I

Answer 1

Your problem is the dependency of spring batch spring-boot-starter-batch that has a spring-boot-starter-jdbc transitive maven dependency.

Spring Batch is a framework for building reliable and fault tolerance enterprise batch jobs. It supports many features like restarting a failed batch, recording the status of the batch execution and so on. In order to achieve that Spring Batch uses a database schema to store the status of the registered jobs, the auto-configuration already provides you the basic configuration of the required data source and it is this configuration that requires the relational database configuration.

To solve this you must include some database driver like mysql, h2, etc. to configure the url.

Update: Just for getting start you can configure your application.yml like below:

spring:
  datasource:
    driver-class-name: org.h2.Driver
    url: jdbc:h2:mem:localhost;DB_CLOSE_ON_EXIT=FALSE
    username: admin
    password:

and of course in your pom.xml include the h2 dirver like this:

<?xml version="1.0" encoding="UTF-8"?>
<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>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

....
    </dependencies>
...

</project>

The motivation, because you can not use mongo for this purpose, is that the usage of mongo is provided only for item readers and writers and not for managing the internal database of Spring Batch that is an internal schema, not a business schema. The query is plain SQL query and the internal abstraction relies on a relational database. It is necessary to have a database with ACID capability because every batch reads and writes a chunk of work and saves that information in order to restart the job. A NoSql solution is not suitable for this.

At the end you have configured a relational database in order to prepare Spring Batch for internal capability, the internal abstraction does not rely on mongo only on jdbc. Then mongo can be used but for the business side of the batch via item reader/writer.

I hope that this can help you to clear your doubts.

Answer 2

It can be because you have jpa dependendencies and plugins...

just comment it if not use(build.gradle or pom file)

e. g.

// kotlin("plugin.jpa") version "1.3.61"

// implementation("org.springframework.boot:spring-boot-starter-data-jpa")

Answer 3

I have add this annotation on the main class of my spring boot application and everything work perfectly

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class })

Answer 4

This link helped.

Spring Boot auto-configuration tries to configure beans automatically based on the dependencies added to the classpath. And because we have a JPA dependency (spring-data-starter-jpa) on our classpath, it tries to configure it.

The problem: Spring boot doesn't have the all the info needed to configure the JPA data source i.e. the JDBC connection properties. Solutions:

1. provide the JDBC connection properties (best)
2. postpone supplying connection properties by excluding some AutoConfig classes (temporary - should be removed eventually)

The above link excludes the DataSourceAutoConfiguration.class with

@SpringBootApplication(exclude={DataSourceAutoConfiguration.class})

But this didn't work for me. I instead, had to exclude 2 AutoConfig classes:

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class, XADataSourceAutoConfiguration.class})

Answer 5

This one worked for me, for MySQL: (Application properties)

spring.datasource.url=jdbc:mysql://localhost:3306/db?useSSL=false&useUnicode=true&useJDBCCompliantTimezoneShift=true&
useLegacyDatetimeCode=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=admin
spring.jpa.hibernate.ddl-auto=create
spring.jpa.show-sql=true

Answer 6

If you have a JPA dependency in your pom.xml then just remove it. This solution worked for me.