添加Thymeleaf Layout Dialect时抛出ClassNotFoundException求助

我在新项目中添加Thymeleaf Layout Dialect，按官方文档配置后，启动项目时抛出如下错误：

2024-02-25T17:38:50.309+01:00 ERROR 20500 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Error processing condition on org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration.propertySourcesPlaceholderConfigurer
        at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:60) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:108) ~[spring-context-6.1.4.jar:6.1.4]
        at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:183) ~[spring-context-6.1.4.jar:6.1.4]
        at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:144) ~[spring-context-6.1.4.jar:6.1.4]
        at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:120) ~[spring-context-6.1.4.jar:6.1.4] 
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:428) ~[spring-context-6.1.4.jar:6.1.4]      
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:289) ~[spring-context-6.1.4.jar:6.1.4] 
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:349) ~[spring-context-6.1.4.jar:6.1.4]
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:118) ~[spring-context-6.1.4.jar:6.1.4]  
        at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:788) ~[spring-context-6.1.4.jar:6.1.4]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:606) ~[spring-context-6.1.4.jar:6.1.4]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.2.3.jar:3.2.3]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) ~[spring-boot-3.2.3.jar:3.2.3]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:456) ~[spring-boot-3.2.3.jar:3.2.3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:334) ~[spring-boot-3.2.3.jar:3.2.3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1354) ~[spring-boot-3.2.3.jar:3.2.3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) ~[spring-boot-3.2.3.jar:3.2.3]
        at de.sveri.dlist.DlistApplication.main(DlistApplication.java:13) ~[main/:na]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:580) ~[na:na]
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:50) ~[spring-boot-devtools-3.2.3.jar:3.2.3]
Caused by: java.lang.IllegalStateException: Failed to introspect Class [de.sveri.dlist.Config] from ClassLoader [org.springframework.boot.devtools.restart.classloader.RestartClassLoader@5ec05b84]
        at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:483) ~[spring-core-6.1.4.jar:6.1.4]
        at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:360) ~[spring-core-6.1.4.jar:6.1.4]
        at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:417) ~[spring-core-6.1.4.jar:6.1.4]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.lambda$getTypeForFactoryMethod$1(AbstractAutowireCapableBeanFactory.java:750) ~[spring-beans-6.1.4.jar:6.1.4]
        at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708) ~[na:na]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:749) ~[spring-beans-6.1.4.jar:6.1.4]    
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:682) ~[spring-beans-6.1.4.jar:6.1.4]        
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:653) ~[spring-beans-6.1.4.jar:6.1.4]
        at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1644) ~[spring-beans-6.1.4.jar:6.1.4]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:562) ~[spring-beans-6.1.4.jar:6.1.4]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:534) ~[spring-beans-6.1.4.jar:6.1.4]
        at org.springframework.boot.autoconfigure.condition.OnBeanCondition.collectBeanNamesForType(OnBeanCondition.java:247) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getBeanNamesForType(OnBeanCondition.java:240) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getBeanNamesForType(OnBeanCondition.java:230) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchingBeans(OnBeanCondition.java:183) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchOutcome(OnBeanCondition.java:158) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:47) ~[spring-boot-autoconfigure-3.2.3.jar:3.2.3]
        ... 20 common frames omitted
Caused by: java.lang.NoClassDefFoundError: nz/net/ultraq/thymeleaf/layoutdialect/LayoutDialect
        at java.base/java.lang.Class.getDeclaredMethods0(Native Method) ~[na:na]
        at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3578) ~[na:na]
        at java.base/java.lang.Class.getDeclaredMethods(Class.java:2676) ~[na:na]
        at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:465) ~[spring-core-6.1.4.jar:6.1.4]
        ... 36 common frames omitted
Caused by: java.lang.ClassNotFoundException: nz.net.ultraq.thymeleaf.layoutdialect.LayoutDialect
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) ~[na:na]
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) ~[na:na]
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ~[na:na]
        at java.base/java.lang.Class.forName0(Native Method) ~[na:na]
        at java.base/java.lang.Class.forName(Class.java:534) ~[na:na]
        at java.base/java.lang.Class.forName(Class.java:513) ~[na:na]
        at org.springframework.boot.devtools.restart.classloader.RestartClassLoader.loadClass(RestartClassLoader.java:121) ~[spring-boot-devtools-3.2.3.jar:3.2.3]
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ~[na:na]
        ... 40 common frames omitted

以下是我的build.gradle配置：

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.2.3'
    id 'io.spring.dependency-management' version '1.1.4'
    id 'org.graalvm.buildtools.native' version '0.9.28'
}

java {
    sourceCompatibility = '21'
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
    implementation 'nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect:3.3.0'
    developmentOnly 'org.springframework.boot:spring-boot-devtools'
    runtimeOnly 'org.postgresql:postgresql'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

我的配置类：

package de.sveri.dlist;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import nz.net.ultraq.thymeleaf.layoutdialect.LayoutDialect;

@Configuration
public class Config {

    @Bean
    public LayoutDialect layoutDialect() {
        return new LayoutDialect();
    }

}

1. 移除手动配置的Config类 #

Spring Boot的spring-boot-starter-thymeleaf已经自动集成了Thymeleaf Layout Dialect的自动配置逻辑，无需手动创建配置类注册LayoutDialect Bean。手动注册会与自动配置冲突，还可能触发devtools类加载器的加载异常。

2. 刷新依赖确保包完整 #

如果移除配置类后仍报错，执行以下Gradle命令刷新依赖，确保layout dialect的jar包正确下载到本地仓库：

./gradlew clean build --refresh-dependencies

3. 版本兼容性确认（可选） #

当前使用的thymeleaf-layout-dialect:3.3.0与Spring Boot 3.2.3完全兼容（对应Thymeleaf 3.1.x版本），后续若遇到版本适配问题，可核对官方版本对应表确认。

内容的提问来源于stack exchange，提问作者sveri