无法将mysql连接到Spring启动项目

Question

我按照这个https://spring.io/guides/gs/accessing-data-mysql/指南连接mysql db到Spring启动项目

但是在运行应用程序时出现以下错误，我正在生成Spring starter项目，并且在通过Spring工具套件创建项目时仅选择web、mysql和jpa框

2018-03-28 16:48:42.125 ERROR 15452 --- [           main] com.zaxxer.hikari.HikariConfig           : Failed to load driver class com.mysql.jdbc.Driver from HikariConfig class classloader jdk.internal.loader.ClassLoaders$AppClassLoader@782830e
2018-03-28 16:48:42.128  WARN 15452 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource
2018-03-28 16:48:42.130  INFO 15452 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2018-03-28 16:48:42.142  INFO 15452 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-03-28 16:48:42.143 ERROR 15452 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource:

    Property: driverclassname
    Value: com.mysql.jdbc.Driver
    Origin: "driverClassName" from property source "source"
    Reason: Unable to set value for property driver-class-name

Action:

Update your application's configuration

以下是application.properties

spring.jpa.hibernate.ddl-auto=create
spring.datasource.url=jdbc:mysql://localhost:3306/world
spring.datasource.username=root
spring.datasource.password=admin

和pom.xml

<?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>proj.mine</groupId>
    <artifactId>training-app-2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>training-app-2</name>
    <description>traning practive app</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.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>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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


</project>

编辑：添加spring.datasource.driver-类名=com.mysql.jdbc.驱动程序在application.properties，错误仍然存在

2018-03-28 17:55:05.641  WARN 3140 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver
2018-03-28 17:55:05.643  INFO 3140 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2018-03-28 17:55:05.656  INFO 3140 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-03-28 17:55:05.662 ERROR 3140 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:587) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:312) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at proj.mine.TrainingApp2Application.main(TrainingApp2Application.java:10) [classes/:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:579) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    ... 18 common frames omitted
Caused by: java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver
    at org.springframework.util.Assert.state(Assert.java:94) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineDriverClassName(DataSourceProperties.java:224) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.initializeDataSourceBuilder(DataSourceProperties.java:176) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.createDataSource(DataSourceConfiguration.java:43) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Hikari.dataSource(DataSourceConfiguration.java:81) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Unknown Source) ~[na:na]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    ... 19 common frames omitted

Answer 1

仅供参考，当我将 Spring Boot 应用程序从 H2 更改为 mySQL 时，我遇到了类似的问题。

我正在使用Gradle（而不是Maven）。我也在使用STS。

我只是忘记运行刷新 Gradle 项目后将其添加到我的 build.gradle 文件：

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web")
    ...
    // Use MySQL Connector-J
    compile 'mysql:mysql-connector-java'

在执行“刷新Gradle项目”并重建/重新启动我的应用程序后，问题消失了。

Answer 2

似乎应用程序可能没有使用正确的类路径运行，因为它似乎难以找到 mysql 驱动程序。您是否正在尝试通过 IDE 运行应用程序？

尝试使用项目目录中的命令行通过maven运行应用程序：

./mvnw-spring-boot:运行

如果这有效，那么这是IDE的问题，由于某种原因，它在运行应用程序时没有提供正确的类路径。我不熟悉STS，但在IntelliJ中有像“自动导入pom”这样的选项来保持IDE对项目的视图与pom同步。

Answer 3

尝试添加 mysql 连接器驱动程序版本并从以下位置删除作用域标记：

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