无法将 mysql 连接到 spring 引导项目

Unable to connect mysql to spring boot project

我正在按照这个 https://spring.io/guides/gs/accessing-data-mysql/ 指南将 mysql 数据库连接到 spring 引导项目

但在 运行 应用程序时出现以下错误,我正在生成 spring 启动项目,并且在通过 spring 创建项目时仅选择 web、mysql 和 jpa 框工具套件

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: 在 application.properties 中添加了 spring.datasource.driver-class-name=com.mysql.jdbc.Driver,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[=15=](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

似乎应用程序可能 运行 不是正确的类路径,因为它似乎难以找到 mysql 驱动程序。您是否正在尝试通过 IDE 来 运行 应用程序?

尝试运行使用项目目录中的命令行通过 maven 连接应用程序:

./mvnw spring-boot:run

如果这有效,那么这是 IDE 的问题,由于某种原因,它在 运行 连接您的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 "auto import pom" 这样的选项来保持 IDE 的项目视图与 pom 同步。

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签:

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

仅供参考,当我将 Spring 启动应用程序从 H2 更改为 mySQL 时遇到了类似的问题。

我使用的是 Gradle(而不是 Maven)。我也在用STS

在我将这个添加到我的 build.gradle 文件后,我只是忘记了 运行 Refresh Gradle Project

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

我的应用 "Refresh Gradle Project" 和 rebuilding/restarting 之后问题就消失了。

也许您缺少 MySQL 连接器依赖项,因此请将其添加到 pom.xml 文件和 运行 项目的依赖项标记中。它可能会解决您的问题。

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

用 DB 版本和数据库更新 pom.xml 文件:

<dependency> 
    <groupId>mysql</groupId> 
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.44</version>
</dependency>

com.zaxxer.hikari.HikariDataSource 需要 spring-boot-starter-data-jdbc依赖项,因此将其添加到您的 pom.xml:

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