我正在尝试解决这个数据源问题，但我暂时还不能解决它。我试过在application.properties中设置spring.datasource.type，但没有解决问题。是配置问题还是依赖问题？或者我必须改变java代码中的一些东西？感谢您的帮助。
例外情况：

Exception encountered during context initialization - cancelling refresh attempt: 
UnsatisfiedDependencyException: Error creating bean with name 'foobazzUtil': Unsatisfied dependency 
expressed through field 'dataSource'; 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 java.lang.NullPointerException

堆栈跟踪：

ERROR org.springframework.boot.SpringApplication [main] Application startup failed
UnsatisfiedDependencyException: Error creating bean with name 'foobazzUtil': Unsatisfied dependency 
expressed through field 'dataSource'; 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 java.lang.NullPointerException

UnsatisfiedDependencyException: Error creating bean with name 'foobazzUtil': Unsatisfied dependency expressed through field 'dataSource'; 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$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
... 39 common frames omitted
Caused by: 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 java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
... 52 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
... 64 common frames omitted
Caused by: java.lang.NullPointerException: null
at java.util.regex.Matcher.getTextLength(Matcher.java:1283)
at java.util.regex.Matcher.reset(Matcher.java:309)
at java.util.regex.Matcher.<init>(Matcher.java:229)
at java.util.regex.Pattern.matcher(Pattern.java:1093)
at java.util.Formatter.parse(Formatter.java:2547)
at java.util.Formatter.format(Formatter.java:2501)
at java.util.Formatter.format(Formatter.java:2455)
at java.lang.String.format(String.java:2940)
at org.springframework.boot.autoconfigure.jdbc.EmbeddedDatabaseConnection.getUrl(EmbeddedDatabaseConnection.java:109)
at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineUrl(DataSourceProperties.java:288)
at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.initializeDataSourceBuilder(DataSourceProperties.java:183)
at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.createDataSource(DataSourceConfiguration.java:42)
at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Tomcat.dataSource(DataSourceConfiguration.java:56)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162)
... 65 common frames omitted

下面是代码的一些部分
foobazzutil.java文件：

@Autowired
javax.sql.DataSource dataSource;

public Connection getConn() throws ClassNotFoundException, SQLException {
    Connection conn = dataSource.getConnection();
    return conn;
}

应用程序属性：

spring.datasource.driver-class-name=oracle.jdbc.OracleDriver
spring.datasource.type=org.apache.tomcat.jdbc.pool.DataSource

spring.datasource.url=jdbc:oracle:thin:@theHost:thePort:theDBName
spring.datasource.username=theUser
spring.datasource.password=thePassword

pom.xml文件

<dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
</dependency>
<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc8</artifactId>
            <version>18.3.0.0</version>
</dependency>
<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
</dependency>