When formatting namenode in Linux:
exception: when encountering exception during format
Error namenode: failed to start namenode_ When home is not set and could not be found
1. Check the path of hdfs-site.xml file namenode
2. If the user’s permission is not enough, give the Hadoop folder user authorization sudo chown – R Hadoop./Hadoop
3. Configure Java in hadoop-env.sh_ HOME
Today, we use STS to import Maven project, install the document installation software and load the document all the way, but after the import project is opened, we always report an error, POM file reports an error, and we can’t find the third-party jar package written by the company. Check it again and again, and there is no error in the process
Colleagues help to check, replace the local library, can not solve. Finally, the settings file of Maven was replaced.
Reason: in the old version of maven, the settings file has not been modified. I don’t know where there is a problem. I can’t find the company’s private jar package. I replaced my colleagues’ settings file to solve the problem.
Idea: POM file error, check Maven installation settings, especially settings file.
@RestController
@RequestMapping("/page")
public class PageController {
@Autowired
private RestTemplate restTemplate;
@GetMapping("/getProduct/{id}")
public Products getProduct(@PathVariable Integer id){
String url = "http://127.0.0.1:9000/product/query/"+id;
Products forObject = restTemplate.getForObject(url, Products.class);
return forObject;
}
}Share an error report solution
Adding @ pathvariable annotation to the request parameter solves the problem
Sqlog can’t connect to MySQL (1045 error)
Error no.1045 solution
1。 Stop MySQL service: run net stop MySQL
2。 Modify my.ini in the MySQL source folder, use the search function to find mysqld, add a line of skip grant tables under it, and save it
3。 Start MySQL service: run net start MySQL
4。 OK, input the connection
Mac OpenSSL not found/loading failed
OpenSSL is a secure socket layer cipher library, including the main cryptographic algorithms, commonly used key and certificate encapsulation management functions and SSL protocol, and provides a wealth of applications for testing or other purposes.
Mac OSX install new OpenSSL
Currently, Mac OSX can install the specified version of OpenSSL through brew.
Confirm the version and location of the installed OpenSSL
$ which openssl
Determine version
$ openssl version
Brew install OpenSSL
$ brew install openssl
Brew update OpenSSL
$ brew upgrade openssl
Brew force link to OpenSSL
$ brew link openssl –force
The above is the introduction of updating OpenSSL under Mac to the latest version.
An error occurred when installing the software through homebrew or other ways
Error running ‘requirements_ osx_ brew_ libs_ install openssl’Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib (LoadError)
It may be caused by not installing or environment variable problems (you can judge by inputting OpenSSL command in the terminal and viewing feedback information)
1. You can solve this problem by re installing OpenSSL
Steps to re install OpenSSL:
Remove OpenSSL (other versions may exist in the removal method. It is recommended to uninstall all versions through uninstall)
brew remove openssl
Uninstall all versions of OpenSSL
brew uninstall –force openssl
Install OpenSSL
brew install openssl
Configure environment variables
echo ‘export PATH=”/usr/local/opt/openssl/bin:$PATH”‘ >& gt; ~/. bash_ profile
In case of an error, first of all, check whether the database can be accessed correctly through MySQL instructions:
it is found that the database can be accessed normally
later, when I observed my configuration, I found that my password was all digital. There would be a little problem with all digital passwords in the YML file, so I need to add ‘single quotation mark to correctly identify them. The correct configuration is as follows:
spring:
datasource:
url: jdbc:mysql://127.0.0.1:3306/mall?useUnicode=true&characterEncoding=utf8&useOldAliasMetadataBehavior=true&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&serverTimezone=UTC
username: root
password: '123456'
driver-class-name: com.mysql.cj.jdbc.Driver
type: com.alibaba.druid.pool.DruidDataSource
My main problem is to delete a library module and submit the code to the server through GIT. When my colleagues pull the code I upload through git, the project still exists in the library and report the dependency error E rror:Project with path ‘XXXX’ could not be found
reason:
When the project is compiled, options corresponding to the related library will appear in gradle.xml automatically generated by. Idea, as shown in the figure
terms of settlement:
Delete the option node of the corresponding library, close the project and re open the compilation.
A more crude way is to delete the. Idea file directly, close the project, and reopen the compilation.
sudo apt install libssl-dev
Error information:
feign.codec.DecodeException: Type definition error: [simple type, class com.rouchi.growth.rpc.dto.classroom.response.SimpleClassRoomResponse]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.rouchi.growth.rpc.dto.classroom.response.SimpleClassRoomResponse` (no Creators, like default constructor, exist): cannot deserialize from Object value (no delegate- or property-based Creator)
at [Source: (ByteArrayInputStream); line: 1, column: 61] (through reference chain: com.rouchi.commons.api.Result["data"]->java.util.ArrayList[0])
The main reason for reporting an error is that the return value cannot construct an object. After checking, it is found that there is an object using Lombok, which only writes @ builder, but does not write @ noargsconstructor
. Therefore, just let go of the comment.
When we use sass in a project, we need to parse sass into CSS through sass loader. If node sass is not installed, sass loader will not work.
Sometimes, if the node sass version is too high, an error will be reported. The log is as follows:
Module build failed: Error: Node Sass version 6.0.0 is incompatible with ^4.0.0.
terms of settlement:
1. Uninstall the installed version of NPM install node sass
2. Install NPM install [email protected]
3. Restart the project
resolvent
Method 1
conda install nomkl
It can be solved after installation
Method 2
Add in code
import os
os.environ["KMP_DUPLICATE_LIB_OK"] = "TRUE"
Problem analysis
The complete error is: OMP: error # 15: initializing libiomp5.dylib, but found libomp.dylib already initialized , the error is caused by repeatedly loading the DLL.
Reference article
Github I ssues:https ://github.com/dmlc/xgboost/issues/1715
The front-end error report is as follows:
[Vue warn]: Error in render: “TypeError: Cannot read property’_t’ of undefined”
It is the compatibility problem between vue and i18n that multi-language configuration is used in the project. The solution is as follows:
Vue.use(iView)
Replace with
Vue.use(iView, {
i18n: function(path, options) {
let value = i18n.t(path, options)
if (value !== null && value !== undefined) {
return value
}
return ''
}
})