Question

我是春季启动新手，并使用弹簧启动开发我的第一个应用程序。以下是我的application.properties文件

server.port=9090
spring.thymeleaf.cache=false


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

spring.datasource.url=jdbc:mysql://localhost:3306/bookstoredatabase

spring.datasource.username=root
spring.datasource.password=
spring.datasource.dbcp2.test-while-idle=true
spring.datasource.dbcp2.validation-query=SELECT 1

spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

这是我的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>com.bookstore</groupId>
    <artifactId>bookstore</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

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

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.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-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
             </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

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

每次运行代码时都会出现以下错误：

Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:587) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:541) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at com.bookstore.BookstoreApplication.main(BookstoreApplication.java:10) [classes/:na]

引起：org.springframework.beans.BeanInstantiationException：无法实例化[com.zaxxer.hikari.HikariDataSource]：工厂方法'dataSource'抛出异常;嵌套异常是java.lang.IllegalStateException：无法加载驱动程序类：com.mysql.jdbc.Driver 在org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate（SimpleInstantiationStrategy.java:185）〜[spring-beans-5.0.5.RELEASE.jar：5.0.5.RELEASE] 在org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod（ConstructorResolver.java:579）〜[spring-beans-5.0.5.RELEASE.jar：5.0.5.RELEASE] ...省略了18个常见帧引起：java.lang.IllegalStateException：无法加载驱动程序类：com.mysql.jdbc.Driver 在org.springframework.util.Assert.state（Assert.java:94）〜[spring-core-5.0.5.RELEASE.jar：5.0.5.RELEASE] at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineDriverClassName（DataSourceProperties.java:224）〜[spring-boot-autoconfigure-2.0.1.RELEASE.jar：2.0.1.RELEASE] 在org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.initializeDataSourceBuilder（DataSourceProperties.java:176）〜[spring-boot-autoconfigure-2.0.1.RELEASE.jar：2.0.1.RELEASE] 在org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.createDataSource（DataSourceConfiguration.java:43）〜[spring-boot-autoconfigure-2.0.1.RELEASE.jar：2.0.1.RELEASE] at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration $ Hikari.dataSource（DataSourceConfiguration.java:81）〜[spring-boot-autoconfigure-2.0.1.RELEASE.jar：2.0.1.RELEASE] at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）〜[na：1.8.0_161] at sun.reflect.NativeMethodAccessorImpl.invoke（Unknown Source）〜[na：1.8.0_161] at sun.reflect.DelegatingMethodAccessorImpl.invoke（Unknown Source）〜[na：1.8.0_161] at java.lang.reflect.Method.invoke（Unknown Source）〜[na：1.8.0_161] 在org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate（SimpleInstantiationStrategy.java:154）〜[spring-beans-5.0.5.RELEASE.jar：5.0.5.RELEASE] ...省略了19个常见帧

我已经尝试了所有关于internetr的解决方案，例如将版本添加到msql-connector-java等，但它们似乎都不起作用。如果somone可以指导我解决这个问题，我将非常沮丧。

Answer 1

据推测，您已经使用Spring Initialzr创建了这个项目，因此您可以尝试运行：

./ mvnw spring-boot：run

而不是eclipse - 可能这是一个日食问题，因为你的错误匹配Unable to connect mysql to spring boot project。如果这确实有效，那么根据该问题的建议，您可以运行＆＃39; mvn clean install＆＃39;重建，然后应该能够做＆＃39; Maven＆gt;更新项目＆＃39;来自eclipse（或将其设置为自动同步 - 请参阅How do I get my Eclipse-Maven project to automatically update its classpath when I change a dependency in my pom.xml file?）

Answer 2

似乎默认情况下像spring boot第一次需要mysql连接。在build.gradle中创建项目时包含mysql连接器，我在依赖项中使用以下行来解决

runtimeOnly'mysql：mysql-connector-java'

application.yml

> spring: 
>     application:
>         name: applicationevent
>         version: 1.0
>     datasource:
>         driverClassName: com.mysql.jdbc.Driver

无法加载驱动程序类：com.mysql.jdbc.Driver使用Eclipse

2 个答案: