Tag Archives: mysql

Solution to error 2059 reported on MySQL 8 via Navicat link error information:

#Error message:

the reason for this error is the encryption rule MySQL in versions before MySQL 8_ native_ Password, and the encryption rule after MySQL 8 is caching_ sha2_ password。 There are two ways to solve this problem. One is to update the Navicat driver to solve this problem, and the other is to modify the encryption rules of MySQL user login to MySQL_ native_ password。 The second method is adopted here
# solution
log in to the database
set the password to never expire

alter user 'root'@'localhost' identified by 'root' password expire never;

Set the encryption rule to MySQL_ native_ password

alter user 'root'@'localhost' identified with mysql_native_password by 'root';

Access Navicat again and you will be prompted that the connection is successful

Android Studio Error: Error:moudle not specified [How to Solve]

Android studio solves error: mouse not specified

When using Android studio for builder apks, if you find that you can’t degub,

No module can be specified during configuration, as shown in (borrow a figure)

The reason for the problem is that the grade files are not synchronized effectively.

1. First ensure grade Synchronization is complete.

2. Perform manual synchronization

Old as version   Click Tools – > Android—> Sync Project With Gradle Files

The new version (I am the new version) is shown in the figure:

Generally, you can debug, and the module has been configured

[Solved] Python import Error: pip –upgrade Error: ERROR: Cannot uninstall ‘dnspython‘. It is a distutils installed

Background:
today we use package to install the module dnspython

[[email protected] ~] wget http://www.dnspython.org/kits/1.9.4/dnspython-1.9.4.tar.gz
[[email protected] ~] tar -xvf dnspython-1.9.4.tar.gz
[[email protected] ~] cd dnspython-1.9.4/
[[email protected] dnspython-1.9.4] python3 setup.py install

Solution process
1. Enter Python and import reports an error (problem found)

[[email protected] ~] python3
Python 3.8.5 (default, Nov  7 2021, 21:47:38) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import dns.resolver
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/python3/lib/python3.8/site-packages/dns/resolver.py", line 26, in <module>
    import dns.message
  File "/usr/local/python3/lib/python3.8/site-packages/dns/message.py", line 175
    return '<DNS message, ID ' + `self.id` + '>'
                                 ^
SyntaxError: invalid syntax

2. Try upgrading (– upgrade) and find that it still can’t be installed

[[email protected] ~] pip3 install dnspython --upgrade
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Requirement already satisfied: dnspython in /usr/local/python3/lib/python3.8/site-packages (1.9.4)
Collecting dnspython
  Downloading https://pypi.tuna.tsinghua.edu.cn/packages/f5/2d/ae9e172b4e5e72fa4b3cfc2517f38b602cc9ba31355f9669c502b4e9c458/dnspython-2.1.0-py3-none-any.whl (241 kB)
     |████████████████████████████████| 241 kB 898 kB/s            
Installing collected packages: dnspython
  Attempting uninstall: dnspython
    Found existing installation: dnspython 1.9.4
ERROR: Cannot uninstall 'dnspython'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.

3. A new error occurred while attempting to uninstall

[[email protected] ~] pip3 uninstall dnspython
Found existing installation: dnspython 1.9.4
ERROR: Cannot uninstall 'dnspython'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.

4. If the command cannot be unloaded, delete the file manually

[[email protected] ~] cd /usr/local/python3  #Go to the directory where python is installed
[[email protected] python3] find ./-name "*package*" #Fuzzy search package
./lib/python3.8/site-packages
./lib/python3.8/site-packages/setuptools/package_index.py
./lib/python3.8/site-packages/setuptools/__pycache__/package_index.cpython-38.pyc
./lib/python3.8/site-packages/setuptools/__pycache__/package_index.cpython-38.opt-1.pyc
......
[[email protected] python3] cd lib/python3.8/site-packages/ #Find site-packages from the above results and go to this directory
[[email protected] site-packages] ll  
total 96
drwxr-xr-x. 4 root root  4096 Nov 16 17:18 dns
-rw-r--r--. 1 root root  1277 Nov  9 22:31 dnspython-1.9.4-py3.8.egg-info
....
[[email protected] site-packages] rm -rf dnspython-1.9.4-py3.8.egg-info   #Delete all files containing the module name

5. Reinstall and import successfully after installation

[[email protected] site-packages] pip3 install dnspython #reinstall
[[email protected] site-packages] python3
Python 3.8.5 (default, Nov  7 2021, 21:47:38) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import dns.resolver
>>> exit

[Linux Docker Mirror] MYSQL Run sql Script Error: Failed to open file ‘/home/mydatabase.sql‘, error: 2

Failed to open file ‘/ home/mydatabase. SQL’, error: 2 when running SQL script in docker image MySQL in Linux

Today, an error occurred when using docker in centos7 to start MySQL and run SQL script files. The error information is as follows:

mysql> source /home/mydatabase.sql;
ERROR: 
Failed to open file '/home/mydatabase.sql', error: 2

After checking the Internet, the cause of the error should be the problem of path matching. The default path is the installation path of MySQL, so MySQL can only access all directories and files under its source directory. The solution is to directly specify the SQL script file to run when logging in. The specific steps are as follows:
first log in to MySQL and create the database to be used. The name of the database I created is Mydatabase1

[email protected]: mysql -uroot -p 
Enter password: 

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> create database mydatabase1;

Exit MySQL and log in again by running SQL script files

# Here mydatabase1 is the database created in the first step, and the file after'<' is the path of the sql script file to be run
[email protected]: mysql -uroot -p mydatabase1 < /home/mydatabase.sql

log in again and find that the file has run successfully

[email protected]: mysql -uroot -p 
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| mydatabase1        |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> use mydatabase1;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed

mysql> show tables;
+-----------------------------+
|    Tables_in_mydatabase1    |
+-----------------------------+
| t_disk                      |
| t_crl                       |
| t_menu                      |
| t_user                      |
+-----------------------------+
4 rows in set (0.00 sec)

Supplement:

# Docker start MySQL command under CentOS7
docker pull mysql:5.7
docker run -tid --name mysql -e MYSQL_ROOT_PASSWORD=root -p 3306:3306 mysql:5.7
docker exec -it mysql /bin/bash
mysql -uroot -p
Enter password:

Exception occurred when Django created app: from exc ^ syntaxerror: invalid syntax

Execute command Python   manage.py   startapp   Myjango

  App reports an error: file “manage. Py”, line 16) from exc ^ syntax error: invalid syntax

reason:

Python 3 is installed, but Python is used for execution

solve:

Change Python to python3 and execute the above command

python3 manage.py   startapp   myjango

[Solved] java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corres

0. Foreword: this error is an error reported by using mybatis in the spring boot project to query a piece of data in the database according to the ID value

1. Error message

2021-11-14 15:37:38.168 ERROR 9936 --- [nio-8086-exec-7] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.jdbc.BadSqlGrammarException: 
### Error querying database.  Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
### The error may exist in file [E:\smallTools\idea\code\spring\springboot-new-2021_11_09\springboot-new-mybatis\target\classes\mybatis\mapper\BookMapper.xml]
### The error may involve com.feng.mybatis.mapper.BookMapper.getBookById-Inline
### The error occurred while setting parameters
### SQL: select * from book where id={#id}
### Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
; bad SQL grammar []; nested exception is java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1] with root cause

java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120) ~[mysql-connector-java-8.0.27.jar:8.0.27]

2. Mapper.xml file content

<select id="getBookById" parameterType="com.feng.mybatis.bean.Book">
        select * from book where id={#id}
</select>

3. Error reason: the SQL statement is written incorrectly. It should be where id = #{id}

<select id="getBookById" parameterType="com.feng.mybatis.bean.Book">
        select * from book where id=#{id}
</select>

Error running ‘Application‘: Command line is too long [How to Solve]

2021.11.18

When idea starts a new project, a pop-up prompt error is encountered

Error running ‘xxx Application’:Command line is too lang. Shorten command line for Application or aalso for Spring Boot default configuration

Error reason: the springboot project startup command is too long

Solution:

The first method (protest is effective)

Step 1: find the idea/workspace.xml file in the project, and then find <component name="PropertiesComponent"> </component > tag, as shown below

step2:Add a line to the component tag < property name="dynamic.classpath" value="true"/>, as shown below

Restart the project.

[Solved] workbench ssl connection error ssl is required but the server

Background

Workbench connection error SSL connection error SSL is required but the server, as shown in the figure below

Solution:

stay https://stackoverflow.com/questions/69824631/mysql-workbench-ssl-connection-error-ssl-is-required-but-the-server-doesnt-sup/69828778 To find a solution, select if availablefor use SSL. However, it is found that the latest version of MySQL workbench 8.0.27 does not have this option. So I downloaded the old version MySQL workbench 8.0.16 , modified the SSL option, and the test results are shown in the figure below
in consideration of downloading workbench to log in, I have prepared the download address for your convenience.

https://sourceforge.net/projects/generic-software/files/workbench/

[Solved] ERROR com.alibaba.druid.pool.DruidDataSource – init datasource error, url jdbcmysql

Error reporting when deploying an open source project

ERROR com.alibaba.druid.pool.DruidDataSource - init datasource error, url jdbcmysql://

Obviously, there is a database connection error

But after eliminating the error, I can find the real cause of the error

Database connection address error

Network problems

Wrong user name and password

Finally, it was found that there was a problem with the MySQL driver version of the open source project, which was inconsistent with the MySQL I installed

Solution:

Go to POM.XML and delete the version information of MySQL, which can be used by default, as shown below

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

[Solved] Whitelabel Error Page This application has no explicit mapping for /error, so you are seeing this as

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.Mon Nov 15 20:44:52 CST 2021
There was an unexpected error (type=lnternal Server Error, status=500).
Could not open JPA Entity/Manager for transacton, nested exception is org.hibernate.exceptionGenericDBCException:
Unable to acquireJDBCConnection

During the debugging of idea, I encountered a problem on the browser side. I found it for many days and finally solved it. That is, the JDBC version of the connection between idea and MySQL does not match. Let’s share the method below
if you see an error, it is probably a JDBC connection problem. First, check the configured MySQL user name, password and URL

After making sure that everything is correct, check whether my MySQL version corresponds to the idea version. Before I made an error, the MySQL jar package in the idea is 5.0, but my idea version is higher than mysql, so I can’t connect. Then I go to the MySQL 8.0 jar package under the official website, import it into the idea, and then change the JDBC version in pom.xml


  • In the higher version of JDBC, spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver is generally added with a cj.

This is the previous
this is the current

later, there will be no JDBC connection problem when running on the server side! This is my problem solved, others may have more situations. Here only represents my own solution!

ERROR c.z.hikari.pool.HikariPool:594 restartedMain HikariPool-1 -Exception

  [problem description]: when starting the springboot project, the following stack error is reported

32.014 ERROR c.z.hikari.pool.HikariPool    :594  restartedMain                    HikariPool-1 - Exception during pool initialization.
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:833)
        at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:453)
        at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246)
        at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198)
        at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138)
        at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364)
        at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206)
        at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476)
        at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561)
        at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115)
        at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112)
        at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:158)
        at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:116)
        at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:79)
        at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:330)
        at org.springframework.boot.jdbc.EmbeddedDatabaseConnection.isEmbedded(EmbeddedDatabaseConnection.java:184)
        at org.springframework.boot.jdbc.init.DataSourceScriptDatabaseInitializer.isEmbeddedDatabase(DataSourceScriptDatabaseInitializer.java:64)
        at org.springframework.boot.sql.init.AbstractScriptDatabaseInitializer.isEnabled(AbstractScriptDatabaseInitializer.java:87)
        at org.springframework.boot.sql.init.AbstractScriptDatabaseInitializer.initializeDatabase(AbstractScriptDatabaseInitializer.java:74)
        at org.springframework.boot.sql.init.AbstractScriptDatabaseInitializer.afterPropertiesSet(AbstractScriptDatabaseInitializer.java:65)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524)
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:338)
        at com.abc.wiki.WikiApplication.main(WikiApplication.java:19)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        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.NativeSocketConnection.connect(NativeSocketConnection.java:89)
        at com.mysql.cj.NativeSession.connect(NativeSession.java:144)
        at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:953)
        at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823)
        ... 42 common frames omitted
Caused by: java.net.ConnectException: Connection timed out: connect
        at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
        at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
        at java.net.Socket.connect(Socket.java:589)
        at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155)
        at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
        ... 45 common frames omitted

[cause of problem]: when debugging the project locally today, the WiFi connected to the computer changed, resulting in the change of IP, which finally led to this problem.

[solution]: modify the configuration of the project connection database to a new IP address.