java微服务的异常

1.依赖异常

须知：
【如果项目的结构是单个模块的，需要给每个单个模块添加起步依赖 spring-boot-starter-parent，指定版本】
【如果项目的结构是子父模块的，只需要给父模块添加起步依赖 spring-boot-starter-parent，指定版本，所有子模块引入父模块就行】

配置文件

你指定了该项目的启动端口号是 8080
你使用了阿里的 nacos 注册中心组件，定义了服务名 weather-service ,及其 Nacos注册中心的地址及端口号 localhost:8848
定义了集群 cluster-name ：SH
定义了隔离空间 namespace：bf 6106 fa-ed 78-4 a 43-bf 22-779594 e 16 a 4 c

依赖文件

这里你可以看出该项目的结构是单个模块, 所以得加起步依赖 spring-boot-starter-parent，指定版本
这里使用了 nacos 注册中心，得加 spring-cloud 依赖和 spring-cloud-alibaba 依赖 , spring-cloud-alibaba 是根据 spring-cloud 开发的，所以使用 spring-cloud-alibaba 的所有组件都必须添加 spring-cloud 依赖，还得加 spring-cloud-starter-alibaba-nacos-discovery nacos 的注册中心依赖
而底下使用了 <dependencyManagement> <dependencies> 标签 spring-cloud-alibaba-dependencies ，spring-cloud-dependencie 统一了其组件下所有的依赖版本

server:  port: 8080  spring:  #注册服务到Nacos  application:  name: weather-service #服务名  cloud:  nacos:  discovery:  server-addr: localhost:8848 #Nacos注册中心的地址及端口号  cluster-name: SH  namespace: bf6106fa-ed78-4a43-bf22-779594e16a4c

<?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>cn.itcast</groupId>  <artifactId>xiaohua-service</artifactId>  <version>1.0-SNAPSHOT</version>  <packaging>jar</packaging>  <!--  war: 传统web项目  jar（默认）：java项目   spring boot项目统一打包方式jar  pom：父工程-->  <!--jdk编译版本-->  <properties>  <java.version>1.8</java.version>  </properties>  <!--spring boot父工程-->  <parent>  <groupId>org.springframework.boot</groupId>  <artifactId>spring-boot-starter-parent</artifactId>  <version>2.3.4.RELEASE</version>  <relativePath/> <!-- lookup parent from repository -->  </parent>  <dependencies>  <!--        导入nacos注册中心组件-->  <dependency>  <groupId>com.alibaba.cloud</groupId>  <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>  </dependency>  <!--spring boot整合junit起步依赖-->  <dependency>  <groupId>org.springframework.boot</groupId>  <artifactId>spring-boot-starter-test</artifactId>  <scope>test</scope>  <exclusions>                <exclusion>  <groupId>org.junit.vintage</groupId>  <artifactId>junit-vintage-engine</artifactId>  </exclusion>  </exclusions>  </dependency>  <!--spring boot整合springmvc起步依赖-->  <dependency>  <groupId>org.springframework.boot</groupId>  <artifactId>spring-boot-starter-web</artifactId>  </dependency>  <!--spring boot整合mp起步依赖-->  <dependency>  <groupId>com.baomidou</groupId>  <artifactId>mybatis-plus-boot-starter</artifactId>  <version>3.4.2</version>  </dependency>  <!--lombok依赖-->  <dependency>  <groupId>org.projectlombok</groupId>  <artifactId>lombok</artifactId>  </dependency>  <!--fastjson的依赖-->  <dependency>  <groupId>com.alibaba</groupId>  <artifactId>fastjson</artifactId>  <version>1.2.76</version>  </dependency>  <!--apache工具包，提供大量工具类，简化操作，eg:判断字符串是否为""字符串...  StringUtils.isEmpty()            StringUtils.isBlank()        -->        <dependency>  <groupId>commons-lang</groupId>  <artifactId>commons-lang</artifactId>  <version>2.6</version>  </dependency>  <!--mysql驱动-->  <dependency>  <groupId>mysql</groupId>  <artifactId>mysql-connector-java</artifactId>  <scope>runtime</scope>  </dependency>  <!--durid连接池依赖-->  <dependency>  <groupId>com.alibaba</groupId>  <artifactId>druid-spring-boot-starter</artifactId>  <version>1.1.23</version>  </dependency>  <dependency>            <groupId>com.alibaba.cloud</groupId>  <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>  </dependency>  </dependencies>  <dependencyManagement>        <dependencies>  <dependency>  <groupId>org.springframework.cloud</groupId>  <artifactId>spring-cloud-dependencies</artifactId>  <version>Greenwich.RELEASE</version>  <type>pom</type>  <scope>import</scope>  </dependency>  <dependency>                <groupId>com.alibaba.cloud</groupId>  <artifactId>spring-cloud-alibaba-dependencies</artifactId>  <version>2.1.0.RELEASE</version>  <type>pom</type>  <scope>import</scope>  </dependency>  </dependencies>  </dependencyManagement>  <build>        <plugins>  <!--spring boot项目打jar包插件  只有引入该插件，打成jar包才可以使用java -jar 运行  -->  <plugin>  <groupId>org.springframework.boot</groupId>  <artifactId>spring-boot-maven-plugin</artifactId>  <version>2.4.5</version>  </plugin>  </plugins>  </build>  
</project>

2. Nacos 程序没启动

问题

当 Nacos 程序没启动时/ Nacos 没有指定单体启动时（Nacos 默认集群启动) ，会导致 Nacos 服务启动失败

java">2024-11-02 00:08:41.354 ERROR 37164 --- [           main] c.a.c.n.registry.NacosServiceRegistry    : nacos registry, weather-service register failed...NacosRegistration{nacosDiscoveryProperties=NacosDiscoveryProperties{serverAddr='localhost:8848', endpoint='', namespace='', watchDelay=30000, logName='', service='weather-service', weight=1.0, clusterName='DEFAULT', namingLoadCacheAtStart='false', metadata={preserved.register.source=SPRING_CLOUD}, registerEnabled=true, ip='192.168.240.94', networkInterface='', port=8080, secure=false, accessKey='', secretKey=''}},java.lang.IllegalStateException: failed to req API:/nacos/v1/ns/instance after all servers([localhost:8848]) tried: failed to req API:localhost:8848/nacos/v1/ns/instance. code:500 msg: java.net.ConnectException: Connection refused: connect

解决

查找 nacos 是否启动

启动 Nacos 服务，指定其单体执行

3. Linux 的静态 ip 失效

查询 ip addr ，静态ip 没分配

尝试重启网络，无效果

解决方案如下

4. Feign 的异常

1. Feign 请求参数异常（2）

错误原因是： feign 的请求参数不完全

6:09:05: 856  INFO 58348 --- [           main] com.hmall.search.feignTest               : No active profile set, falling back to default profiles: default
16:09:06:180  WARN 58348 --- [           main] o.m.s.mapper.ClassPathMapperScanner      : No MyBatis mapper was found in '[com.hmall]' package. Please check your configuration.
16:09:06:229  INFO 58348 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=24dddd9d-1203-3d7a-841c-d55b879e19b0
16:09:06:541  WARN 58348 --- [           main] c.n.c.sources.URLConfigurationSource     : No URLs will be polled as dynamic configuration sources.
16:09:06:541  INFO 58348 --- [           main] c.n.c.sources.URLConfigurationSource     : To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
16:09:06:547  WARN 58348 --- [           main] c.n.c.sources.URLConfigurationSource     : No URLs will be polled as dynamic configuration sources.feign.FeignException$NotFound: [404] during [GET] to [http://item-service/list?page=1&size=5] [ItemClientFeign#pagelist(Integer,Integer)]: [{"timestamp":"2024-11-16T08:09:10.069+00:00","status":404,"error":"Not Found","message":"","path":"/list"}]

解决

2. FeignClient 注解注册重复

***************************
APPLICATION FAILED TO START
***************************Description:
The bean ‘xxx.FeignClientSpecification‘ could not be registered.The bean 'xxx.FeignClientSpecification' could not be registered. A bean with that name has already been defined and overriding is disabled.Action:Consider renaming one of the beans or enabling overriding by setting spring.main.allow-bean-definition-overriding=true

解决

方法 1 多个 feign 接口使用@FeignClient 注解调用同一个名称的微服务时，启动时会引发此异常。修改即可
方法 2：在配置文件中增加配置 spring.main.allow-bean-definition-overriding=true

3. Feign 远程 A调用 B，A 异常，B 也会报错（B 报的错）

A 服务报的错会比较模糊

feign. FeignException$InternalServerError: [500] during [GET] to [http://user-service/user/getUserById?id=2] [UserClientFeign #getUserById (Long)]: [{“timestamp”: “2024-11-18 T14:39:28.153+00:00”,“status”: 500,“error”: “Internal Server Error”,“message”: “”,“path”: “/user/getUserById”}]

B 服务就很清楚

SQL: SELECT id, username, password, phone, status, balance, create_time, update_time FROM tb_user WHERE id=?
Cause: com. Mysql. Jdbc. Exceptions. Jdbc 4. MySQLSyntaxErrorException: Unknown column ‘create_time’ in ‘field list’
; bad SQL grammar []; nested exception is com. Mysql. Jdbc. Exceptions. Jdbc 4. MySQLSyntaxErrorException: Unknown column ‘create_time’ in ‘field list’] with root cause
Com. Mysql. Jdbc. Exceptions. Jdbc 4. MySQLSyntaxErrorException: Unknown column ‘create_time’ in ‘field list’
At java. Base/jdk. Internal. Reflect. NativeConstructorAccessorImpl. NewInstance 0 (Native Method) ~[na: na]
At java. Base/jdk.Internal.Reflect.NativeConstructorAccessorImpl.NewInstance (NativeConstructorAccessorImpl. Java:62) ~[na: na]
At java. Base/jdk.Internal.Reflect.DelegatingConstructorAccessorImpl.NewInstance (DelegatingConstructorAccessorImpl. Java:45) ~[na: na]
At java. Base/java.Lang.Reflect.Constructor.NewInstance (Constructor. Java:490) ~[na: na]

5. 网关的异常

1. Yml配置请求头看似不生效(网关, gateway）

其实你去看前端页面的请求头，是没有设置的请求头，是因为网关是在前端发送请求后，后端服务前才生效的，所以访问后端服务时，需要先通过网关
处理，你可以给网关设置访问校验

有三种配置方式

设置默认过滤器添加请求头

spring:  
application:  name: gatway-service  
cloud:  nacos:  discovery:  server-addr: localhost:8848  gateway:  routes:  - id: item-service  uri: lb://item-service  predicates:  - Path=/item/**  #给所有路由添加请求头
default-filters:- AddRequestHeader=authorization, 2

设置单个路由设置过滤器添加请求头

spring:  application:  name: gatway-service  cloud:  nacos:  discovery:  server-addr: localhost:8848  gateway:  routes:  - id: item-service  uri: lb://item-service  predicates:  - Path=/item/**  
#给单个路由添加请求头filters:  - AddRequestHeader=authorization,2