intellij idea springboot solution can not read configuration file

Problem Description

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After running Spring Boot project, the following error:

***************************
APPLICATION FAILED TO START
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Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class

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).

 

 Or when the value can not be imported @Value annotation appears,

 Could not resolve placeholder 'elasticsearch.host' in value "${elasticsearch.host}"

　　

You can use the following solution

Problems and Solutions

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Cause of the problem: Mybatis not find a suitable load classes, in fact, most of the spring - datasource - url is not loaded successfully, analyze the reasons as follows.

1. DataSourceAutoConfiguration be loaded automatically.

2. Is not configured datasource - - url spring  property.

3. spring - datasource - url  address configured format issue.

4. Configuring  spring - datasource - url of the file is not loaded.

 

Internet gives these types of solutions.

Option One (resolve Cause 1)

Autoconfig exclude this class. After starting to run properly.

@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class})

　　

Option II (resolve Cause 2)

Did not add the database configuration information in application.properties/ or application.yml file.

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/read_data?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver

Option Three (3 to address the causes)

Referenced database address in the spring xml configuration file so it is necessary to: such as escaping but does not need to escape in application.properties/ or application.yml files, error and the correct way to write the below.

# Error example 
spring.datasource.url = jdbc: MySQL \: // 192.168.0.20 \: 1504 / = to true f_me setUnicode & characterEncoding = utf8?
 # Correct example 
spring.datasource.url = jdbc: MySQL: // 192.168.0.20:1504 / f_me? setUnicode = true & char

Option IV (to address the causes 4)

To file pom <build> </ build> add the following. Yml or properties to ensure that the file can be scanned and properly loaded successfully. (Intellij idea running, not scan src folder (java folder) arranged inside file)

<resources>
   <resource>
      <directory>src/main/java</directory>
      <includes>
         <include>**/*.yml</include>
         <include>**/*.properties</include>
      </includes>
      <filtering>false</filtering>
   </resource>
   <resource>
      <directory>src/main/resources</directory>
      <includes>
         <include>**/*.yml</include>
         <include>**/*.properties</include>
      </includes>
      <filtering>false</filtering>
   </resource>
</resources>