从 Spring Boot 2.7.2 升级到 Spring Boot 3.0.0-SNAPSHOT：引起：java.lang.NoClassDefFoundError：javax/servlet/http/HttpServletRequest

Question

从 Spring Boot 2.7.2 升级到 Spring Boot 3.0.0-SNAPSHOT。

错误

Caused by: java.lang.NoClassDefFoundError: javax/servlet/http/HttpServletRequest

完整日志https://gist.github.com/donhuvy/4eb218437077e58f996937ea255fb359

如何修复它？

Answer 1

很简单，只需将 import 语句中的 javax 替换为 jakarta 即可。例如

旧的进口声明：

import javax.servlet.http.HttpServletRequest;

新的进口声明：

import jakarta.servlet.http.HttpServletRequest;

原因 - 从 Java EE 跳转到 Jakarta EE9。

Answer 2

之所以发生这种情况，是因为在 Spring Boot 3 中，他们更改了 Tomcat 的版本（如果我没记错的话，是 9），并且其中所有对 Javax 的引用都被 Jakarta 替换了。据我所知，您的问题是 Swagger，我设法使用快照版本解决了它。就我而言，我使用它进行研究，最终版本将于 2022 年 11 月发布，这不是什么大问题。我相信这里可以帮助你。这是项目 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 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>3.0.0-M2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>br.com.erudio</groupId>
    <artifactId>rest-with-spring-boot-and-java-erudio</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>rest-with-spring-boot-and-java-erudio</name>
    <properties>
        <java.version>18</java.version>
        <dozer.version>6.4.0</dozer.version>
        <springdoc.version>2.0.0-M1</springdoc.version>
        <testcontainers.version>1.16.3</testcontainers.version>
        <rest-assured.version>4.5.0</rest-assured.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.hateoas</groupId>
            <artifactId>spring-hateoas</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-xml</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-yaml</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springdoc</groupId>
            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
            <version>${springdoc.version}</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-core</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-mysql</artifactId>
        </dependency>
        
        <dependency>
            <groupId>com.github.dozermapper</groupId>
            <artifactId>dozer-core</artifactId>
            <version>${dozer.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.rest-assured</groupId>
            <artifactId>rest-assured</artifactId>
            <version>${rest-assured.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>mysql</artifactId>
            <version>${testcontainers.version}</version>
            <scope>test</scope>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
               <groupId>org.flywaydb</groupId>
               <artifactId>flyway-maven-plugin</artifactId>
               <configuration>
                  <url>jdbc:mysql://localhost:3306/rest_with_spring_boot_erudio?useTimezone=true&amp;serverTimezone=UTC&amp;useSSL=false</url>
                  <user>root</user>
                  <password>admin123</password>
               </configuration>
               <dependencies>
                  <dependency>
                     <groupId>mysql</groupId>
                     <artifactId>mysql-connector-java</artifactId>
                     <version>${mysql.version}</version>
                     <exclusions>
                        <exclusion>
                           <artifactId>slf4j-api</artifactId>
                           <groupId>org.slf4j</groupId>
                        </exclusion>
                     </exclusions>
                  </dependency>
               </dependencies>
            </plugin>
        </plugins>
    </build>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>