Thymeleaf dependency causes "Error: Could not find or load main class" in Spring tool suite

Question

我刚刚下载了 STS 并启动了一些 maven 项目并且它工作正常，但是当我开始使用 thymeleaf 时它不起作用。

我看到项目名称上有感叹号，我收到此错误 错误：找不到或无法加载主程序 class.

我尝试在 POM 中自己添加它的依赖项，我得到了那个错误，一旦我删除它们它就消失了！

我还尝试创建一个 "Spring Starter Project" 并选择要添加的依赖项 "Web and Thymeleaf"，在创建项目后我立即在测试依赖项 的 POM 中看到语法错误传输失败 org.springframework.boot:spring-boot-starter-test:jar

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
</dependency>

当我删除它及其 class 时，我得到了上面相同的错误。

这是我的 POM：

<?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>

<groupId>com.example</groupId>
<artifactId>demo-2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>demo-2</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.4.2.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

</dependencies>

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


</project>

Answer 1

尝试更新您的 Maven 存储库，请先尝试：

mvn dependency:purge-local-repository

Description:

When run on a project, remove the project dependencies from the local repository, and optionally re-resolve them. Outside of a project, remove the manually given dependencies.

然后尝试：

mvn dependency:copy-dependencies

Description:

Goal that copies the project dependencies from the repository to a defined location.

在我看来，您的本地 Maven 存储库不包含 thymeleaf 依赖项。

Answer 2

删除失败的下载后问题已解决：

来自 CMD：

cd %userprofile%\.m2\repository
for /r %i in (*.lastUpdated) do del %i

然后更新项目。

它重新下载了依赖项，它工作得很好。

Thymeleaf dependency causes "Error: Could not find or load main class" in Spring tool suite

Thymeleaf dependency causes "Error: Could not find or load main class" in Spring tool suite

java

spring

pom.xml

maven

thymeleaf