解决一些Springboot启动报错问题

2023年3月5日源码参考

项目启动报错比调bug更加难受

概要：近日在学习Springcloud微服务。配置服务注册中心，一切妥妥当当，但还是报了一个让我崩溃的问题：org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
翻译一下这句话：启动内置tomcat失败。
具体报错信息如下：

org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:155) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at com.ecjtu.demo.DemoApplication.main(DemoApplication.java:15) [classes/:?]
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:126) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:409) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:174) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:179) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:152) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	... 8 more
Caused by: java.lang.IllegalStateException: StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[] failed to start
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.rethrowDeferredStartupExceptions(TomcatWebServer.java:172) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:110) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:409) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:174) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:179) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:152) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	... 8 more

出了错，当然得去看配置文件application.yml，pom.xml,程序入口类。这三个。我们一个一个来看。

application.yml(application.properties)

极其简单的配置，但是跑起来不是问题。
程序入口类

当然也是没有问题的，就是加了一个@EnableEurekaServer注解，表示是一个服务注册中心
pom.xml
放在最后不是没道理的

<?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.ecjtu</groupId>
    <artifactId>demo</artifactId>
    <version>0.01-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>demo</name>
    <!--<url>http://www.example.com</url>-->
    
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring-cloud.version>Finchley.SR1</spring-cloud.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.2.RELEASE</version>
        <relativePath/>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <!-- 下面的配置有些是额外加的，无需在意--!>
    build>
        <finalName>demo</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <jvmArguments>
                         -server -Xmx2048m -Xms2048m -XX:MaxPermSize=512m
                         -Xdebug
                         -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=9090
                    </jvmArguments>
                    <mainClass>com.lelian.Application</mainClass>
                    <fork>true</fork>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

我是左看右看，就是解决不了，但是如果我把@EnableEurekaServer注解和关于eureka的配置都去掉，就完全是一个普通的Springboot项目，但是项目可以跑起来。我也是很奇怪啊！！！
最后想了一下是不是java版本的问题，网上许多教程都是在java8的环境下搭建的，但是我用的java版本是java10，这是一个你知道但是不知道他有什么特性的版本，然后百度了一下他的特性，从java9开始，模块化的概念使得JAXB默认没有加载；jaxb-api是存在jdk中的，只是默认没有加载而已，我们需要手动引入。要问这个jaxb-api是什么作用，大家可以自行百度，反正我引入了这个模块问题得到了解决。

 jaxb模块引用 - start
        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-core</artifactId>
            <version>2.2.11</version>
        </dependency>
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
        </dependency>
        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-impl</artifactId>
            <version>2.2.11</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jaxb</groupId>
            <artifactId>jaxb-runtime</artifactId>
            <version>2.2.10-b140310.1920</version>
        </dependency>
        <dependency>
            <groupId>javax.activation</groupId>
            <artifactId>activation</artifactId>
            <version>1.1.1</version>
        </dependency>
         jaxb模块引用 - end

最终，项目跑起来了。
在这里插入图片描述
以上是我遇到的问题和解决的办法，不知道对于大家有没用。若有不当之处还望各位指正。

版权声明：本文为baidu_41437297原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。

原文链接：https://blog.csdn.net/baidu_41437297/article/details/83016778

上一篇文章
静态内部类实例化下一篇文章
git submodule 基本用法