java - Thymeleaf 依赖导致 Spring 工具套件中出现 "Error: Could not find or load main class"

Question

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

我在项目名称上看到一个感叹号，并且收到此错误错误:无法找到或加载主类。

我尝试在 POM 中自行添加其依赖项，但出现该错误，一旦删除它们，该错误就会消失!

我还尝试创建一个“Spring Starter Project”并选择要添加的依赖项“Web and Thymeleaf”，在项目创建后，我在测试依赖项的 POM 中看到语法错误无法传输 org.springframework.boot:spring-boot-starter-test:jar

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

当我删除它及其类时，我得到了上面相同的错误。

现在这是我的 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，首先尝试:

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。