試圖按照https://spring.io/guides/gs/accessing-data-mysql/ 中的指南進行操作，但是當我啟動我的 java 應用程序時，它顯示以下錯誤：Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.Reason: Failed to determine a suitable driver classAction: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).這是我的 application.property：spring.jpa.hibernate.ddl-auto=createspring.datasource.url=jdbc:mysql://localhost:3306/db_currencyspring.datasource.username=springuserspring.datasource.password=ThePassword數據庫創建遵循以下指南：mysql> create database db_example; -- Create the new databasemysql> create user 'springuser'@'localhost' identified by 'ThePassword'; mysql> grant all on db_example.* to 'springuser'@'localhost';我的 build.gradle 是：buildscript {    repositories {        mavenCentral()    }    dependencies {        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.0.5.RELEASE")    }}apply plugin: 'java'apply plugin: 'eclipse'apply plugin: 'idea'apply plugin: 'org.springframework.boot'apply plugin: 'io.spring.dependency-management'bootJar {    baseName = 'gs-accessing-data-mysql'    version =  '0.1.0'}repositories {    mavenCentral()}sourceCompatibility = 1.8targetCompatibility = 1.8dependencies {    compile("org.springframework.boot:spring-boot-starter-web")    // JPA Data (We are going to use Repositories, Entities, Hibernate, etc...)    compile 'org.springframework.boot:spring-boot-starter-data-jpa'    // Use MySQL Connector-J    compile 'mysql:mysql-connector-java'    testCompile('org.springframework.boot:spring-boot-starter-test')}