我对构建web应用程序是新手。我正在尝试使用springboot和mysql数据库构建简单的web应用程序。我在mysql workbench中创建了早期的数据库，但我不断得到这些异常：java.sql.sqlnontransientconnectionexception:无法创建到数据库服务器的连接。尝试重新连接3次。放弃。原因：com.mysql.cj.exceptions.cjexception:拒绝访问用户“”@'localhost'（使用密码：否）
我的application.properties文件：
spring.datasource.url=jdbc:mysql://localhost:3306/appautoreconnect=true&usessl=false
spring.datasource.data username=myusername
spring.datasource.data password=mypassword
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.mysql5innodbdialect
spring.jpa.hibernate.ddl auto=更新
logging.level.org.hibernate.sql=调试
logging.level.org.hibernate.type=跟踪
我的pom.xml依赖项：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

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

谢谢你的帮助