java - Spring 启动 : Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured

Question

当我运行我的网络应用程序时抛出以下错误。

Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaConfiguration': 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$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class

抛出的错误描述如下，

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


    Action:

    Consider the following:<br>
        If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
<br>    If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

引用后this answer ，我知道我必须对我的 pom.xml 文件做一些更改。但我不知道要更改什么，甚至 StackOverflow 上类似类型的问题也无法帮助我解决这个问题。

我的 pom.xml 如下(创建项目时我添加了“Web”、“JPA”、“MySQL”依赖项)，

    <?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>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.3.RELEASE</version>
            <relativePath/> <!-- lookup parent from repository -->
        </parent>
        <groupId>com.example</groupId>
        <artifactId>SL2INDUSTRY</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>SL2INDUSTRY</name>
        <description>Demo project for Spring Boot</description>

        <properties>
            <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>
            <!-- https://mvnrepository.com/artifact/org.apache.tomcat.embed/tomcat-embed-jasper -->
            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-jasper</artifactId>
                <scope>provided</scope>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-tomcat -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
                <version>2.1.3.RELEASE</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.dataformat/jackson-dataformat-xml -->
            <dependency>
                <groupId>com.fasterxml.jackson.dataformat</groupId>
                <artifactId>jackson-dataformat-xml</artifactId>
                <version>2.9.8</version>
            </dependency>
        </dependencies>

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

    </project>

Plese note that I don't need to deal with H2 databases in this situation so H2 is not a solution for me.

编辑: application.properties 文件

spring.mvc.view.suffix=.jsp

Answer 1

如果您阅读了您的错误痕迹:

Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaConfiguration': 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$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class

您会注意到他正在尝试使用 hikari 数据源来配置与 bd 的连接。这是怎么回事？

你用的是spring boot 2，这个版本的spring boot改变了默认配置。

正如你在这个地址看到的:

https://www.baeldung.com/spring-boot-hikari#spring-boot-2

In Spring Boot 2, Hikari is the default DataSource implementation.

This is what’s changed from Spring Boot 1.x:

· the dependency to Hikari is now automatically included in spring-boot-starter-data-jpa

· the discovery algorithm that automatically determines a DataSource implementation now prefers Hikari over TomcatJDBC (see the reference manual).

Thus, we have nothing to do if we want to use Hikari in an application based on Spring Boot 2.x.

Hikari 的配置不同。

然后，我想你想使用 tomcat 连接池。你可以这样做:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    <exclusions>
        <exclusion>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jdbc</artifactId>
    <version>9.0.10</version>
</dependency>

This will exclude Hikari by default from your spring jpa configuration and then you will need tomcat-jdbc. The you can configure de datasource:

This simple approach allows us to get Spring Boot using a Tomcat connection pool without having to write a @Configuration class and programmatically define a DataSource bean.

It’s also worth noting that in this case, we’re using the H2 in-memory database. Spring Boot will autoconfigure H2 for us, without having to specify a database URL, user, and password.

We just need to include the corresponding dependency in the “pom.xml” file and Spring Boot will do the rest for us.

Alternatively, it’s possible to skip the connection pool scanning algorithm that Spring Boot uses and explicitly specify a connection pooling datasource in the “application.properties” file, using the “spring.datasource.type” property:

spring.datasource.type=org.apache.tomcat.jdbc.pool.DataSource
// other spring datasource properties
spring.datasource.url=...
spring.datasource.username=...
spring.datasource.password=...
...

这里有禁用 Hikari 和配置 tomcat 的完整引用:

https://www.baeldung.com/spring-boot-tomcat-connection-pool

如果你想使用 Hikari，配置是不同的:

https://www.baeldung.com/spring-boot-hikari

但这两个选项之一将解决您的问题。