required a bean of type 'javax.sql.DataSource' that could not be found.

Description:

Field dataSource in com.rjj.screw.ScrewApplication required a bean of type 'javax.sql.DataSource' that could not be found.

The injection point has the following annotations:
    - @org.springframework.beans.factory.annotation.Autowired(required=true)

The following candidates were found but could not be injected:
    - Bean method 'dataSource' in 'JndiDataSourceAutoConfiguration' not loaded because @ConditionalOnClass did not find required class 'org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType'
    - Bean method 'dataSource' in 'XADataSourceAutoConfiguration' not loaded because @ConditionalOnClass did not find required class 'javax.transaction.TransactionManager'


Action:

Consider revisiting the entries above or defining a bean of type 'javax.sql.DataSource' in your configuration.

2020-08-30 16:49:01.968 ERROR 13937 --- [           main] o.s.test.context.TestContextManager      : Caught exception while allowing TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener@7a1a3478] to prepare test instance [com.rjj.screw.ScrewApplicationTests@113e13f9]

java.lang.IllegalStateException: Failed to load ApplicationContext

出现了这个问题，找了好多，

下边这个是我的pom

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.rjj</groupId>
    <artifactId>screw</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>screw</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <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>

        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.30</version>
        </dependency>

        <!-- screw核心 -->
        <dependency>
            <groupId>cn.smallbun.screw</groupId>
            <artifactId>screw-core</artifactId>
            <version>1.0.3</version>
        </dependency>

　　　　//之前没有加这个，换了mybatis-spring-boot-start也不行。这个是最原始的jdbc配置
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        


        <!--mysql driver-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.20</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

 我这里的问题：

 mysql-driver这个包只是驱动包，不是mysql的加载我们的配置的包，以前我们都是自己写连接，这里jdbc这个包就是springboot中加载我们配置的包。所以，不加就报错了，我这里使用的就是最初始的

mysql的连接加载方式，所以添加其他的方式。比如mybatis就还是有问题。

这个问题看每个人的情况来解决