java.lang.ClassNotFoundException: org.springframework.util.unit.DataSize

spring boot 启动报错。

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/util/unit/DataSize
	at org.springframework.boot.convert.StringToDataSizeConverter.getConvertibleTypes(StringToDataSizeConverter.java:40)
	at org.springframework.core.convert.support.GenericConversionService$Converters.add(GenericConversionService.java:507)
	at org.springframework.core.convert.support.GenericConversionService.addConverter(GenericConversionService.java:105)
	at org.springframework.boot.convert.ApplicationConversionService.addApplicationConverters(ApplicationConversionService.java:107)
	at org.springframework.boot.convert.ApplicationConversionService.configure(ApplicationConversionService.java:91)
	at org.springframework.boot.convert.ApplicationConversionService.<init>(ApplicationConversionService.java:52)
	at org.springframework.boot.convert.ApplicationConversionService.<init>(ApplicationConversionService.java:45)
	at org.springframework.boot.convert.ApplicationConversionService.getSharedInstance(ApplicationConversionService.java:71)
	at org.springframework.boot.SpringApplication.configureEnvironment(SpringApplication.java:486)
	at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:346)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:306)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
	at com.zt.SpringApplication.main(SpringApplication.java:25)
Caused by: java.lang.ClassNotFoundException: org.springframework.util.unit.DataSize
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 14 more

	<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<!-- spring版本号 -->
		<!-- <spring.version>5.0.8.RELEASE</spring.version> 版本错误-->
	</properties>

spring 版本错误。
https://stackoverflow.com/questions/53593754/java-lang-noclassdeffounderror-org-springframework-util-unit-datasize-while-run