Author Archives: Robins

How to Solve Vue3 Import lodash error

Solution: Add the following codes under shims-vue.d.ts folder:

declare module 'lodash'

All codes

/* eslint-disable */
declare module '*.vue' {
  import type { DefineComponent } from 'vue'
  const component: DefineComponent<{}, {}, any>
  export default component
}
	
declare module 'lodash'

[Solved] Springboot connect MySQL error: errorcode 0, state 08s01

preface

For a project that has not been maintained for a long time, you need to check some data. Re run the project and find create connection sqlexception, and the specific error messages are errorcode 0, state 08s01.

Springboot version 2.5, MySQL 8.0

Error reporting details

2021-12-18 22:47:14.834 ERROR 20196 --- [reate-940563698] com.alibaba.druid.pool.DruidDataSource   : create connection SQLException, url: jdbc:mysql://localhost:3306/renrenfast?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai, errorCode 0, state 08S01

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:827)
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:447)
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:237)
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:156)
	at com.alibaba.druid.filter.FilterAdapter.connection_connect(FilterAdapter.java:786)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:150)
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:218)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:150)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1572)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1636)
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2550)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
	at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
	at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:340)
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.negotiateSSLConnection(NativeAuthenticationProvider.java:777)
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(NativeAuthenticationProvider.java:486)
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:202)
	at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1348)
	at com.mysql.cj.NativeSession.connect(NativeSession.java:163)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:947)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:817)
	... 11 common frames omitted
Caused by: javax.net.ssl.SSLHandshakeException: Invalid Alert message: no sufficient data
	at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:131)
	at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:117)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:336)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:292)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:283)
	at java.base/sun.security.ssl.Alert$AlertMessage.<init>(Alert.java:196)
	at java.base/sun.security.ssl.Alert$AlertConsumer.consume(Alert.java:236)
	at java.base/sun.security.ssl.TransportContext.dispatch(TransportContext.java:185)
	at java.base/sun.security.ssl.SSLTransport.decode(SSLTransport.java:171)
	at java.base/sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1408)
	at java.base/sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1314)
	at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:440)
	at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:411)
	at com.mysql.cj.protocol.ExportControlled.performTlsHandshake(ExportControlled.java:316)
	at com.mysql.cj.protocol.StandardSocketFactory.performTlsHandshake(StandardSocketFactory.java:188)
	at com.mysql.cj.protocol.a.NativeSocketConnection.performTlsHandshake(NativeSocketConnection.java:99)
	at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:331)
	... 18 common frames omitted

Configuration details

spring:
    datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        druid:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://localhost:3306/xxx?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai

Solution:

Just add &useSSL=false

spring:
    datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        druid:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://localhost:3306/xxx?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false

Effect detection

It’s really running! It seems that

How to Solve IDEA @Autowired Error

Problem: @Autowired is red due to configuration problems.

Solution:

Click file -> settings -> Editor-> Inspections

As shown in the figure: enter spring core

Click autowriting for bean class to change the level from error to warning

Click OK, and the idea will not be red.

Resolved.

[Solved] MySQL Execute update error: error code: 1175

When using Mysql to execute update, if the primary key is not used in the where condition, the following error will be reported and the update cannot be executed.

Exception content: error code: 1175 You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column To disable safe mode, toggle the option in Preferences -> SQL Queries and reconnect.

Solution:
this is because MySQL runs in the safe updates mode. Modify the database security mode to allow the update or delete commands to be executed under non primary key conditions.

Execute command:

SET SQL_SAFE_UPDATES = 0;

[Solved] Vue prettier error: error Delete `␍` prettier/prettier

The console error message is as follows

F:\aaaaa\dice-front\store\tag.js
  1:30  error  Delete `␍`  prettier/prettier
  2:11  error  Delete `␍`  prettier/prettier
  3:3   error  Delete `␍`  prettier/prettier
  4:1   error  Delete `␍`  prettier/prettier
  5:27  error  Delete `␍`  prettier/prettier

Solution 1: automatically identify the end

Add this to the first set in the project .pretierrc file.

"endOfLine": "auto"

Solution 2:

In the project In the .editorconfig file, Change end_of_line to CRLF. (used globally if possible)

Reason: git ends with CRLF and LF on different computers

The newline characters of text files under windows and Linux are inconsistent.

During line feed
windows uses both carriage return character Cr (carriage return character) and line feed character LF (linefeed character)
Mac and Linux systems only use the line feed LF
the old MAC system used the carriage return CR.

[Solved] IDEA plug-in jrbel hot deployment cannot be started error

The idea plug-in jrbel hot deployment fails to start, and an error is reported: jrebel JVMTI [fat] a fatal error occurred while processing the base Java classes The JVM has been shut down (1).

due to JDK charges, openjdk has been replaced. Recently, it cannot be used due to hot deployment. The reason for the error is the openjdk problem. Maybe the openjdk file has been rewritten. Just replace it with another JDK.

[Solved] Idea Build error. The symbol — Lombok cannot be found

The Lombok annotation is used here, and the get and set methods cannot be used during entity class compilation.

The build method is gradle

The following settings can be solved:

How to Solve Swagger error: IllegalStateException

Swagger reported an error, IllegalStateException

I encountered a novel mistake today. Take a note.

Because of the project problem, I imported the swagger dependency into the common module. Then, because common is introduced into the gateway, check the dependency tree and confirm that the gateway also introduces the swagger dependency by default.

Due to the introduction of a problem, an error is reported when starting the gateway. The error is as follows:

java.lang.IllegalStateException: Failed to introspect Class [com.tang.config.SwaggerConfiguration] from ClassLoader [sun.misc.Launcher$AppClassLoader@18b4aac2]
	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:481)
	at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:358)
	at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:414)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory
Caused by: java.lang.NoClassDefFoundError: springfox/documentation/spring/web/plugins/Docket
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
	at java.lang.Class.getDeclaredMethods(Class.java:1975)
	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:463)
	... 33 common frames omitted
Caused by: java.lang.ClassNotFoundException: springfox.documentation.spring.web.plugins.Docket
	at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 37 common frames omitted

Because the error occurred after the swagger dependency was introduced. So I preliminarily determined that the error occurred in the two swagger dependencies I imported.

        <!-- swagger -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
        </dependency>

After querying the boss on stackoverflow, the answer is that swagger needs web dependency when it is started. If it does not exist, an error will be reported. I tried to add and found

A respectful error is reported on the console:

**********************************************************

Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway at this time. Please remove spring-boot-starter-web dependency.

**********************************************************

Because it was an error found in the gateway. Therefore, it is obvious that the spring cloud gateway integrates weblux and thus the web. Therefore, adding spring-boot-starter-web to the project will cause the above error.

<dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-gateway-server</artifactId>
      <version>2.2.7.RELEASE</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webflux</artifactId>
      <version>2.3.8.RELEASE</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-loadbalancer</artifactId>
      <version>2.2.7.RELEASE</version>
      <scope>compile</scope>
      <optional>true</optional>
    </dependency>

Solution:

Because the gateway in the project does not need to integrate swagger, when introducing the basic module package with swagger in the gateway configuration, it only needs to be in POM XML settings <exclusions></exclusions>

<exclusions>
    <exclusion>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
    </exclusion>
    <exclusion>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
    </exclusion>
</exclusions>

Finally, because the related configuration classes of swagger are also written in the basic module. An error will also be reported because the swagger dependency is not imported. At this time, you only need to ignore the injection in the gateway gateway startup class.

@ComponentScan(excludeFilters = @ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE, value = SwaggerConfiguration.class))

How to Solve Mybatisplusinterceptor error

Reason: the version of mybatis plus generator which is dependent on mybatis plus is low

Solution:

Add dependency

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>3.4.0</version>
</dependency>

[Solved] init datasource error, url: jdbc:mysql://localhost:3306/test

Problem description

The following error message is suddenly thrown when starting the project today:

[16:14:32.735][ERROR][com.alibaba.druid.pool.DruidDataSource][main] init datasource error, url: jdbc:mysql://localhost:3306/test
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server

reason

Finally, it is concluded that MySQL needs to specify whether to connect with SSL in the higher version

Solution:

Set usessl = false, and change the connection URL as follows

jdbc:mysql://localhost:3306/test?useSSL=false

[Solved] Idea Run Error: Error running ‘Application‘: Command line is too long

Modify .idea/workspace.xml file:

<!--Configurate in the tag of component name="PropertiesComponent"-->
<component name="PropertiesComponent">
	<!--ADD-->
	<property name="dynamic.classpath" value="true" />
</component >

Then re-run the project

[Solved] Python2 Install tensorflow Error: class DescriptorBase(metaclass=DescriptorMetaclass), SyntaxError: invalid syntax

When Python 2 installs tensorflow, test after the installation is completed:

import tensorflow as tf

Will report an error:

Traceback (most recent call last):
File “<stdin>”, line 1, in <module>
File “/home/zhaokai/.local/lib/python2.7/site-packages/tensorflow/__init__.py”, line 28, in <module>
from tensorflow.python import pywrap_tensorflow # pylint: disable=unused-import
File “/home/zhaokai/.local/lib/python2.7/site-packages/tensorflow/python/__init__.py”, line 52, in <module>
from tensorflow.core.framework.graph_pb2 import *
File “/home/zhaokai/.local/lib/python2.7/site-packages/tensorflow/core/framework/graph_pb2.py”, line 7, in <module>
from google.protobuf import descriptor as _descriptor
File “/home/zhaokai/.local/lib/python2.7/site-packages/google/protobuf/descriptor.py”, line 113
class DescriptorBase(metaclass=DescriptorMetaclass):
^
SyntaxError: invalid syntax

The solution is to re-install protobuf:

pip install protobuf==3.17.3

then Import tensorflow again.

ProgrammerAH

Programmer Guide, Tips and Tutorial

Author Archives: Robins

How to Solve Vue3 Import lodash error

[Solved] Springboot connect MySQL error: errorcode 0, state 08s01

How to Solve IDEA @Autowired Error

[Solved] MySQL Execute update error: error code: 1175

[Solved] Vue prettier error: error Delete `␍` prettier/prettier

[Solved] IDEA plug-in jrbel hot deployment cannot be started error

[Solved] Idea Build error. The symbol — Lombok cannot be found

How to Solve Swagger error: IllegalStateException

How to Solve Mybatisplusinterceptor error

[Solved] init datasource error, url: jdbc:mysql://localhost:3306/test

[Solved] Idea Run Error: Error running ‘Application‘: Command line is too long

[Solved] Python2 Install tensorflow Error: class DescriptorBase(metaclass=DescriptorMetaclass), SyntaxError: invalid syntax