spring boot数据jpa无法连接到mysql数据库

Question

I try to connect to mysql using spring-boot-starter-data-jpa and hibernate by this example but get

...
2016-07-28 13:20:49.021 ERROR 7765 --- [ main] osboot.SpringApplication : Application startup failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceAutoConfiguration$NonEmbeddedConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active)

...

application.properties:

    # DataSource settings: set here your own configurations for the database 
# connection. In this example we have "netgloo_blog" as database name and 
# "root" as username and password.
spring.datasource.url = jdbc:mysql://localhost:3306/db
spring.datasource.username = db
spring.datasource.password = pass

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

# Keep the connection alive if idle for a long time (needed in production)
spring.datasource.testWhileIdle = true
spring.datasource.validationQuery = SELECT 1

# Show or not log for each sql query
spring.jpa.show-sql = true

# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto = update

# Naming strategy
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy

# Use spring.jpa.properties.* for Hibernate native properties (the prefix is
# stripped before adding them to the entity manager)

# The SQL dialect makes Hibernate generate better SQL for the chosen database
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

project structure in eclipse:

build.gradle :

 buildscript {
  repositories {
        mavenCentral()
  }
  dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-  plugin:1.3.6.RELEASE")
  }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'

jar {
    baseName = 'gs-accessing-data-jpa'
    version =  '0.1.0'
}

repositories {
    mavenCentral()
    maven { url "https://repository.jboss.org/nexus/content/repositories/releases" }
}

sourceCompatibility = 1.8
targetCompatibility = 1.8

dependencies {
    compile("org.springframework.boot:spring-boot-starter-data-jpa")
    compile group: 'org.springframework.boot', name: 'spring-boot-starter-web', version: '1.3.6.RELEASE'
    compile group: 'mysql', name: 'mysql-connector-java', version: '6.0.3' 

   //also tried

    runtime group: 'mysql', name: 'mysql-connector-java', version: '6.0.3' 
    runtime "org.apache.tomcat:tomcat-jdbc:7.0.47"

    testCompile("junit:junit")
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.3'
}

Answer 1

You did not add the driver class

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

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

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

Check for these dependencies as well

Answer 2

Can you add runtime dependency in gradle as opposed to compile time dependency on the MYSQL Driver jar ?

dependencies {
  //compile "mysql:mysql-connector-java:6.0.3"
  runtime "mysql:mysql-connector-java:6.0.3"
  runtime "org.apache.tomcat:tomcat-jdbc:7.0.47"
}

Answer 3

do you have database driver on the classpath? have you set property spring.datasource.driver-class-name ?

For more details, see http://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-sql.html