Java Spring Boot-可部署War-ClassNotFoundException

我一直在尝试创建一个springboot可部署war，以便将其部署到tomcat服务器上（我想指出，它作为一个可执行jar运行良好）。但是，我在Tomcat 9服务器上遇到了以下异常（我有一个运行在IntelliJ中，另一个运行在linux服务器上，两者都会引发相同的异常）：

据我所知，它存在于spring上下文jar中，通过maven将其正确地拉入构建中。我用spring boot创建了一个超级简单的演示应用程序，我真的不明白为什么会遇到这个问题

pom.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.4</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <groupId>com.example</groupId>
  <artifactId>demo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <name>demo</name>
  <description>Demo project for Spring Boot</description>

  <properties>
    <java.version>11</java.version>
    <start-class>com.example.demo.DemoApplication</start-class>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>5.3.5</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.5</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <excludes>
            <exclude>
              <groupId>org.projectlombok</groupId>
              <artifactId>lombok</artifactId>
            </exclude>
          </excludes>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

我完全不知道为什么我会碰到这个ClassNotFoundException。查看war文件，我确实在WEB-INF/lib文件夹中看到了所有适当的库。我上面粘贴的两个文件实际上就是我试图运行的所有项目

我看过这本指南：

---

如果我删除扩展SpringBootServletializer，那么错误就会消失，但是我当然没有一个功能正常的SpringBootWar文件。

你导入了SpringBootStarterWeb吗？这个类位于spring boot starter web导入的上下文库中。显然，我在Tomcat lib文件夹中有一个库，它包含了所有依赖库。。。正好有一个spring依赖项。。。因此，它引入了一个旧版本的spring，这导致了一场冲突。将jar换成不包含所有依赖项的jar后，它被加载。

是的，我已经导入了它。我的问题最终是Tomcat lib文件夹中的一个坏库，出于某种原因，它绑定了旧版本的spring。我用一个不捆绑所有依赖项的库替换了lib，我的问题就解决了。

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.4</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <groupId>com.example</groupId>
  <artifactId>demo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <name>demo</name>
  <description>Demo project for Spring Boot</description>

  <properties>
    <java.version>11</java.version>
    <start-class>com.example.demo.DemoApplication</start-class>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>5.3.5</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.5</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <excludes>
            <exclude>
              <groupId>org.projectlombok</groupId>
              <artifactId>lombok</artifactId>
            </exclude>
          </excludes>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class DemoApplication  extends SpringBootServletInitializer {
  @Override
  protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
    return application.sources(DemoApplication.class);
  }
  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }

  @RequestMapping(value = "/")
  public String hello() {
    return "Hello World from Tomcat";
  }
}