尝试运行 Spring 启动应用程序时出错。使用名称创建 bean 时出错

Question

我目前正在学习 John Thompson Spring 课程 Spring 框架 5：初学者到大师。尝试构建第一个基本应用程序，但我不断收到错误消息。我试过在网上搜索解决方案，但没有任何效果。

这是 pom.xml 代码：

http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.mycompany.firstspringproject</groupId>
<artifactId>first-spring-project</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>first-spring-project</name>
<description>First project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.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-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</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>

整个文件是根据我在 Spring Initializr 中选择的内容生成的。我不断收到的错误是：

 [INFO] ------------------------------------------------------------------------
 [INFO] BUILD FAILURE
 [INFO] ------------------------------------------------------------------------
 [INFO] Total time: 4.648 s
 [INFO] Finished at: 2018-01-20T21:20:05+01:00
 [INFO] Final Memory: 38M/378M
 [INFO] ------------------------------------------------------------------------
 [ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-          plugin:1.5.9.RELEASE:run (default-cli) on project first-spring-project: An      exception occurred while running. null: InvocationTargetException: Error      creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$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). -> [Help 1]
 [ERROR]
 [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
 [ERROR] Re-run Maven using the -X switch to enable full debug logging.
 [ERROR]
 [ERROR] For more information about the errors and possible solutions, please read the following articles:
 [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

如果您需要更多详细信息，请询问。我会尽力送达的。

Answer 1

您最终得到的错误是：

Cannot determine embedded database driver class for database type NONE.

According to the documentation，您需要定义一些属性，以便 Spring 知道您要与哪个数据库对话。开箱即用，Spring Boot 对此没有合理的默认值。

您需要在 application.properties 中定义的示例：

spring.datasource.url=jdbc:mysql://localhost/test
spring.datasource.username=dbuser
spring.datasource.password=dbpass
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

驱动程序、url 和凭据将根据您托管数据库的位置及其类型而改变。可以找到完整的属性列表 in the Appendix。如果你愿意，你可以嵌入一个 H2 数据库，而不是像上面的例子那样使用 MySql。

Answer 2

查看堆栈跟踪

nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException

Cannot determine embedded database driver class for database type NONE

you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active)

所以请尝试修复您的代码。

检查您的数据源 bean 定义，它是否附加到特定 profile.I 假设您拥有所有数据源，url，属性文件中提供的驱动程序名称.否则 read more here

@Profile("dev")//This is how you attach your bean to profile.
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource dataSource() {
  return DataSourceBuilder.create().build();
}

如果以上为真，那么你应该告诉 spring 容器要使用哪个配置文件（例如 spring.profiles.active=dev），除非它在你的属性中指定文件.Read more here

Answer 3

我认为您的 spring 数据源配置可能不完整，如果没有源很难确定。

根据Andy Wilkinson's answer to a similar issue：

You haven't provided Spring Boot with enough information to auto-configure a DataSource. To do so, you'll need to add some properties to application.properties with the spring.datasource prefix. Take a look at DataSourceProperties to see all of the properties that you can set.

You'll need to provide the appropriate url and driver class name:
spring.datasource.url = …
spring.datasource.driver-class-name = …

但是，如果您的应用程序在设计上根本没有数据源，您可能必须禁用自动配置器，如所述：

It is possible to run a spring boot application without datasource. You must disable the auto configuration for the datasource and may be for JPA also :
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class,HibernateJpaAutoConfiguration.class})

尝试 运行 Spring 启动应用程序时出错。使用名称创建 bean 时出错

Error trying to run Spring boot app. Error creating bean with name

java

spring

pom.xml

maven

spring-boot

尝试运行 Spring 启动应用程序时出错。使用名称创建 bean 时出错