今天将shardingsphere版本改成5.1.0之后项目启动不了了，报错信息如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.apache.shardingsphere.spring.boot.ShardingSphereAutoConfiguration': Initialization of bean failed; nested exception is java.lang.NullPointerException at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:408) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:229) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:723) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:536) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) ~[spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:405) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at com.test.demo.DemoApplication.main(DemoApplication.java:15) [classes/:na] Caused by: java.lang.NullPointerException: null at org.apache.shardingsphere.spring.boot.datasource.DataSourceMapSetter.getDataSource(DataSourceMapSetter.java:92) ~[shardingsphere-jdbc-spring-boot-starter-infra-5.1.0.jar:5.1.0] at org.apache.shardingsphere.spring.boot.datasource.DataSourceMapSetter.getDataSourceMap(DataSourceMapSetter.java:65) ~[shardingsphere-jdbc-spring-boot-starter-infra-5.1.0.jar:5.1.0] at org.apache.shardingsphere.spring.boot.ShardingSphereAutoConfiguration.setEnvironment(ShardingSphereAutoConfiguration.java:122) ~[shardingsphere-jdbc-core-spring-boot-starter-5.1.0.jar:5.1.0] at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces(ApplicationContextAwareProcessor.java:108) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization(ApplicationContextAwareProcessor.java:100) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:415) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1786) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] ... 25 common frames omitted
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.apache.shardingsphere.spring.boot.ShardingSphereAutoConfiguration': Initialization of bean failed; nested exception is java.lang.NullPointerException
从报错信息中可以看到hardingSphereAutoConfiguration创建失败，出现了空指针异常。
根据异常提示从shardingsphere-jdbc-core-spring-boot-starter的源码中找到这么一段代码
private static DataSource getDataSource(Environment environment, String dataSourceName) throws ReflectiveOperationException, NamingException { Map<String, Object> dataSourceProps = (Map)PropertyUtil.handle(environment, String.join("", "spring.shardingsphere.datasource.", dataSourceName), Map.class); Preconditions.checkState(!dataSourceProps.isEmpty(), "Wrong datasource [%s] properties.", dataSourceName); return dataSourceProps.containsKey("jndi-name") ? getJNDIDataSource(dataSourceProps.get("jndi-name").toString()) : DataSourcePoolCreator.create(new DataSourceProperties(dataSourceProps.get("type").toString(), PropertyUtil.getCamelCaseKeys(dataSourceProps))); }
shardingsphere在读取application.yml配置文件中shardingsphere数据源的配置时对读取到的type用了.toString()，也就是spring.shardingsphere.datasource.type不能为空。
检查了配置文件确实没有知道数据源的类型，加上之后再启动项目
发现还是报错但是这次报错不一样了
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.apache.shardingsphere.spring.boot.ShardingSphereAutoConfiguration': Initialization of bean failed; nested exception is java.lang.NoClassDefFoundError: org/apache/tomcat/dbcp/dbcp2/BasicDataSource at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:408) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:229) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:723) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:536) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) ~[spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:405) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.3.5.RELEASE.jar:2.3.5.RELEASE] at com.test.demo.DemoApplication.main(DemoApplication.java:14) [classes/:na] Caused by: java.lang.NoClassDefFoundError: org/apache/tomcat/dbcp/dbcp2/BasicDataSource at org.apache.shardingsphere.infra.datasource.pool.metadata.type.dbcp.TomcatDBCPDataSourcePoolMetaData.getType(TomcatDBCPDataSourcePoolMetaData.java:67) ~[shardingsphere-infra-common-5.1.0.jar:5.1.0] at org.apache.shardingsphere.spi.typed.TypedSPIRegistry.lambda$findRegisteredService$0(TypedSPIRegistry.java:44) ~[shardingsphere-spi-5.1.0.jar:5.1.0] at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174) ~[na:1.8.0_144] at java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1351) ~[na:1.8.0_144] at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126) ~[na:1.8.0_144] at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:498) ~[na:1.8.0_144] at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:485) ~[na:1.8.0_144] at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_144] at java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:152) ~[na:1.8.0_144] at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_144] at java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:464) ~[na:1.8.0_144] at org.apache.shardingsphere.spi.typed.TypedSPIRegistry.findRegisteredService(TypedSPIRegistry.java:44) ~[shardingsphere-spi-5.1.0.jar:5.1.0] at org.apache.shardingsphere.infra.datasource.pool.metadata.DataSourcePoolMetaDataFactory.newInstance(DataSourcePoolMetaDataFactory.java:46) ~[shardingsphere-infra-common-5.1.0.jar:5.1.0] at org.apache.shardingsphere.infra.datasource.props.DataSourceProperties.<init>(DataSourceProperties.java:53) ~[shardingsphere-infra-common-5.1.0.jar:5.1.0] at org.apache.shardingsphere.spring.boot.datasource.DataSourceMapSetter.getDataSource(DataSourceMapSetter.java:92) ~[shardingsphere-jdbc-spring-boot-starter-infra-5.1.0.jar:5.1.0] at org.apache.shardingsphere.spring.boot.datasource.DataSourceMapSetter.getDataSourceMap(DataSourceMapSetter.java:65) ~[shardingsphere-jdbc-spring-boot-starter-infra-5.1.0.jar:5.1.0] at org.apache.shardingsphere.spring.boot.ShardingSphereAutoConfiguration.setEnvironment(ShardingSphereAutoConfiguration.java:122) ~[shardingsphere-jdbc-core-spring-boot-starter-5.1.0.jar:5.1.0] at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces(ApplicationContextAwareProcessor.java:108) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization(ApplicationContextAwareProcessor.java:100) ~[spring-context-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:415) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1786) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.10.RELEASE.jar:5.2.10.RELEASE] ... 25 common frames omitted Caused by: java.lang.ClassNotFoundException: org.apache.tomcat.dbcp.dbcp2.BasicDataSource at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_144] at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_144] at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335) ~[na:1.8.0_144] at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_144] ... 47 common frames omitted
从报错信息中可以看到找不到org.apache.tomcat.dbcp.dbcp2.BasicDataSource，应该是缺少依赖包
从Maven仓库中可以看到shardingsphere-jdbc-core-spring-boot-starter 5.1.0 依赖于tomcat-dbcp 10.0.16或以上版本
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-dbcp</artifactId>
<version>10.0.16</version>
</dependency>
在pom.xml中加入tomcat-dbcp 10.0.16依赖之后项目就能正常启动了