SpringBoot启动失败的原因及其解决方法_Java

前言：

对于springboot的启动失败，相信大家都有经历，但是为什么会启动失败，以及怎么解决都只能通过日志进行查看，在这里，我会将常见的springboot启动失败的报错一一展示

报错：

1：端口占用报错

***************************
application failed to start
***************************
 
description:
the tomcat connector configured to listen on port 8987 failed to start. the port  may already be in use or the connector may be misconfigured.
 
// 配置为监听端口8987的tomcat连接器启动失败。端口可能已经在使用中，或者连接器可能配置错误。
 
action:
verify the connector's configuration, identify and stop any process that's liste ning on port 8987, or configure this application to listen on another port.
 
// 验证连接器的配置，识别并停止端口8987上正在运行的任何进程，或将此应用程序配置为监听另一个端口。

报错：the port may already be in use —> 端口可能已经在使用中
原因：8987 端口被占用
解决：给springboot换一个端口或关闭占用端口的程序。

2：mapper扫描类报错

***************************
application failed to start
***************************
 
description:
 
field clustersdetailsamqmapper in com.ruoyi.clusters.service.impl.clustersdetailsamqserviceimpl required a bean of type 'com.ruoyi.clusters.mapper.clustersdetailsamqmapper' that could not be found.
 
// 在 com.ruoyi.clusters.service.impl.clustersdetailsamqserviceimpl 中的属性 clustersdetailsamqmapper 需要一个类型为'com.ruoyi.clusters.mapper.clustersdetailsamqmapper'的bean，但是找不到它。
 
the injection point has the following annotations:
	- @org.springframework.beans.factory.annotation.autowired(required=true)
 
// 注入点具有以下注释：-@org.springframework.beans.factory.annotation.autowired（必需=true）
 
action:
 
consider defining a bean of type 'com.ruoyi.clusters.mapper.clustersdetailsamqmapper' in your configuration.
 
// 考虑在配置中定义一个类型为'com.ruoyi.clusters.mapper.clustersdetailsamqmapper'的bean。

报错：field xxxmapper in xxx required a bean of type 'xxxmapper' that could not be found. —> 在xxx中的属性xxxmapper 需要一个类型为'xxxmapper'的 bean，但是找不到它。
原因：springboot的启动类没有配置mapper扫描路径或配置的mapper文件扫描路径不对。
解决：在springboot启动类中配置正确的mapper文件扫描，如下：

@springbootapplication
@mapperscan(value = "com.ruoyi.**.mapper")  
// 路径必须与mapper文件在的路径一致，否则依然会报错
public class ruoyiapplication {
    public static void main(string[] args) {
        springapplication.run(ruoyiapplication.class, args);
    }
}

注意：* 指的是下一级目录，** 指的是包含其子目录在内的。

如果mapper文件在com.ruoyi.testa.mapper中，用@mapperscan(value = "com.ruoyi.*.mapper") 是可以的，

如果文件是在com.ruoyi.testa.mytest.mapper中，1个 * 配置依然会找不到这个mapper文件，会报同样的错误，应该用**，@mapperscan(value = "com.ruoyi.**.mapper")。

3.数据库连接问题

***************************
application failed to start
***************************
 
description:
 
failed to configure a datasource: 'url' attribute is not specified and no embedded datasource could be configured.
// 配置数据源失败：没有指定'url'属性，无法配置嵌入的数据源。
 
reason: failed to determine a suitable driver class
// 原因：无法确定合适的驱动程序类
 
action:
 
consider the following:
	if you want an embedded database (h2, hsql or derby), please put it on the classpath.
	if you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).
// 请考虑以下几点：
// 如果你想要嵌入式数据库（h2、hsql或derby），请把它放在classpath(类路径)上。
// 如果要从特定配置文件加载数据库设置，则可能需要激活它（当前没有配置文件处于活动状态）。

报错：failed to determine a suitable driver class —> 没法确定合适的驱动程序类

原因：没有在application.yml中配置数据源（比如druid连接池）或数据库驱动（比如mysql）

加上数据源配置：

# 数据源配置
spring:
    datasource:
        type: com.alibaba.druid.pool.druiddatasource
        driverclassname: com.mysql.cj.jdbc.driver
        druid:
            # 主库数据源
            master:
                url: jdbc:mysql://127.0.0.1:3306/car?useunicode=true&characterencoding=utf8&zerodatetimebehavior=converttonull&usessl=true&servertimezone=gmt%2b8
                username: root
                password: root

加上数据库坐标：

 <!-- mysql驱动包 -->
<dependency>
    <groupid>mysql</groupid>
    <artifactid>mysql-connector-java</artifactid>
</dependency>

4：没有绑定连接池

***************************
application failed to start
***************************
 
description:
 
failed to bind properties under 'spring.datasource.type' to java.lang.class<javax.sql.datasource>:
// 没法把'spring.datasource.type'下的属性绑定到java.lang.class<javax.sql.datasource>：
    property: spring.datasource.type
    // 属性：spring.datasource.type
    value: com.alibaba.druid.pool.druiddatasource
    // 值: com.alibaba.druid.pool.druiddatasource
    origin: class path resource [application-druid.yml]:4:15
    //来源: 类路径资源[application-druid.yml]：4:15
    reason: no converter found capable of converting from type [java.lang.string] to type [java.lang.class<javax.sql.datasource>]
// 原因：找不到能够从类型[java.lang.string]转换为类型[java.lang.class<javax.sql.datasource>]的转换器
 
action:
 
update your application's configuration
// 更新应用程序的配置

原因：没导入druid连接池的坐标，所以找不到com.alibaba.druid.pool.druiddatasource，把druid连接池的坐标正确导入即可

<!--阿里数据库连接池 -->
<dependency>
    <groupid>com.alibaba</groupid>
    <artifactid>druid-spring-boot-starter</artifactid>
</dependency>

5：无法确定合适的jdbc url

***************************
application failed to start
***************************
 
description:
 
failed to configure a datasource: 'url' attribute is not specified and no embedded datasource could be configured.
// 配置数据源失败：没有指定“url”属性，无法配置嵌入的数据源。
 
reason: failed to determine suitable jdbc url
// 原因：无法确定合适的jdbc url
 
action:
 
consider the following:
	if you want an embedded database (h2, hsql or derby), please put it on the classpath.
	if you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).
// 请考虑以下几点：
// 如果你想要嵌入式数据库（h2、hsql或derby），请把它放在类路径上。
// 如果要从特定配置文件加载数据库设置，则可能需要激活它（当前没有激活的配置文件）。

报错：failed to determine suitable jdbc url —> 无法确定合适的jdbc url

原因：
url没有被读取到，配置文件没有生效，其大概原因有以下几点：

系统编码不正确。跑项目之前最好让项目与文件的编码对应起来
可能有和你所在项目平级的配置文件，springboot会优先读取项目同级别目录下的配置文件
idea没有将resource设置为资源目录
检查druidconfig配置类（或配置文件）
检查一下application启动文件的位置，建议将其放在外层：如果springbootapplication启动文件位置在数据库配置druidconfig文件下层，则不会对这个configuration进行扫描，然后去找默认的配置，所以导致failed to determine suitable jdbc url

6：自定义数据源一定要排除springboot自动配置数据源，不然会出现循环引用的问题

description:
 
the dependencies of some of the beans in the application context form a cycle:
// 应用程序上下文中某些bean的依赖关系形成一个循环：
 
   testacontroller (field private com.ruoyi.testa.service.testaservice com.ruoyi.apis.testacontroller.testaservice)
      ↓
   testaserviceimpl (field private com.ruoyi.testa.mapper.testamapper com.ruoyi.testa.service.impl.testaserviceimpl.testamapper)
      ↓
   testamapper defined in file [e:\ideaprojects2018\car\ruoyi-mapper\target\classes\com\ruoyi\testa\mapper\testamapper.class]
      ↓
   sqlsessionfactory defined in class path resource [org/mybatis/spring/boot/autoconfigure/mybatisautoconfiguration.class]
┌─────┐
|  dynamicdatasource defined in class path resource [com/ruoyi/config/druidconfig.class]
↑     ↓
|  masterdatasource defined in class path resource [com/ruoyi/config/druidconfig.class]
↑     ↓
|  org.springframework.boot.autoconfigure.jdbc.datasourceinitializerinvoker
└─────┘

异常出现场景：springboot中自定义datasource数据源
原因：自定义数据源一定要排除springboot自动配置数据源，不然会出现循环引用的问题。
解决：排除spring boot数据源自动配置类

@springbootapplication(exclude = { datasourceautoconfiguration.class })
@mapperscan(value = "com.ruoyi.**.mapper") 
public class ruoyiapplication {
    public static void main(string[] args) {
        springapplication.run(ruoyiapplication.class, args);
    }
}

7：由于缺少servletwebserverfactory bean，无法启动servletwebserverapplicationcontext

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: spring boot ::        (v2.0.3.release)
2020-09-01 11:21:54.103  info 21308 --- [           main] com.smr.bluetooth.devicecommapplication  : starting devicecommapplication on laptop-rm7cn477 with pid 21308 (e:\ideaprojects2018\bluetooth_test\target\classes started by 且随疾风前行 in e:\ideaprojects2018\bluetooth_test)
2020-09-01 11:21:54.106  info 21308 --- [           main] com.smr.bluetooth.devicecommapplication  : no active profile set, falling back to default profiles: default
2020-09-01 11:21:54.133  info 21308 --- [           main] configservletwebserverapplicationcontext : refreshing org.springframework.boot.web.servlet.context.annotationconfigservletwebserverapplicationcontext@770c2e6b: startup date [tue sep 01 11:21:54 cst 2020]; root of context hierarchy
2020-09-01 11:21:54.232  warn 21308 --- [           main] configservletwebserverapplicationcontext : exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.applicationcontextexception: unable to start web server; nested exception is org.springframework.context.applicationcontextexception: unable to start servletwebserverapplicationcontext due to missing servletwebserverfactory bean.
2020-09-01 11:21:54.605 error 21308 --- [           main] o.s.boot.springapplication               : application run failed
org.springframework.context.applicationcontextexception: unable to start web server; nested exception is org.springframework.context.applicationcontextexception: unable to start servletwebserverapplicationcontext due to missing servletwebserverfactory bean.
	at org.springframework.boot.web.servlet.context.servletwebserverapplicationcontext.onrefresh(servletwebserverapplicationcontext.java:155) ~[spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.context.support.abstractapplicationcontext.refresh(abstractapplicationcontext.java:544) ~[spring-context-5.0.7.release.jar:5.0.7.release]
	at org.springframework.boot.web.servlet.context.servletwebserverapplicationcontext.refresh(servletwebserverapplicationcontext.java:140) ~[spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.springapplication.refresh(springapplication.java:759) [spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.springapplication.refreshcontext(springapplication.java:395) [spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.springapplication.run(springapplication.java:327) [spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.springapplication.run(springapplication.java:1255) [spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.springapplication.run(springapplication.java:1243) [spring-boot-2.0.3.release.jar:2.0.3.release]
	at com.smr.bluetooth.devicecommapplication.main(devicecommapplication.java:10) [classes/:na]
caused by: org.springframework.context.applicationcontextexception: unable to start servletwebserverapplicationcontext due to missing servletwebserverfactory bean.
	at org.springframework.boot.web.servlet.context.servletwebserverapplicationcontext.getwebserverfactory(servletwebserverapplicationcontext.java:204) ~[spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.web.servlet.context.servletwebserverapplicationcontext.createwebserver(servletwebserverapplicationcontext.java:178) ~[spring-boot-2.0.3.release.jar:2.0.3.release]
	at org.springframework.boot.web.servlet.context.servletwebserverapplicationcontext.onrefresh(servletwebserverapplicationcontext.java:152) ~[spring-boot-2.0.3.release.jar:2.0.3.release]
	... 8 common frames omitted

报错：unable to start servletwebserverapplicationcontext due to missing servletwebserverfactory bean. （由于缺少servletwebserverfactory bean，无法启动servletwebserverapplicationcontext）

解决：启动类添加@enableautoconfiguration注解即可解决问题

8：依赖冲突

***************************
application failed to start
***************************
 
description:
 
an attempt was made to call a method that does not exist. the attempt was made from the following location:
 
org.apache.catalina.authenticator.authenticatorbase.startinternal(authenticatorbase.java:1319)
 
the following method did not exist:
 
javax.servlet.servletcontext.getvirtualservername()ljava/lang/string;
 
the calling method's class, org.apache.catalina.authenticator.authenticatorbase, was loaded from the following location:
jar:file:/e:/maven/maven-repository/org/apache/tomcat/embed/tomcat-embed-core/9.0.63/tomcat-embed-core-9.0.63.jar!/org/apache/catalina/authenticator/authenticatorbase.class
the called method's class, javax.servlet.servletcontext, is available from the following locations:
 
jar:file:/e:/maven/maven-repository/org/apache/tomcat/servlet-api/6.0.18/servlet-api-6.0.18.jar!/javax/servlet/servletcontext.class
jar:file:/e:/maven/maven-repository/org