應該寫成 jdbc:mysql://localhost:3306/dbSeckill，我在mysql后面少寫了一個冒號。。。

server:
??port:?8888
mybatis:
??mapper-locations:?classpath:mapping/*.xml

spring:
??datasource:
????driver-class-name:?com.mysql.cj.jdbc.Driver
????name:?dbSeckill
????url:?jdbc:mysql//localhost:3306/dbSeckill?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT
????username:?
????password:?

????type:?com.alibaba.druid.pool.DruidDataSource

<?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>2.2.4.RELEASE</version>
????????<relativePath/>?<!--?lookup?parent?from?repository?-->
????</parent>
????<groupId>com.xlx</groupId>
????<artifactId>seckill</artifactId>
????<version>0.0.1-SNAPSHOT</version>
????<name>seckill</name>
????<description>Online?Seckill?Project</description>
????<properties>
????????<java.version>1.8</java.version>
????</properties>
????<dependencies>
????????<dependency>
????????????<groupId>mysql</groupId>
????????????<artifactId>mysql-connector-java</artifactId>
????????????<version>8.0.19</version>
????????????<scope>runtime</scope>
????????</dependency>
????????<dependency>
????????????<groupId>org.springframework.boot</groupId>
????????????<artifactId>spring-boot-starter-data-jdbc</artifactId>
????????</dependency>
????????<dependency>
????????????<groupId>org.springframework.boot</groupId>
????????????<artifactId>spring-boot-starter-data-jpa</artifactId>
????????</dependency>
????????<dependency>
????????????<groupId>org.springframework.boot</groupId>
????????????<artifactId>spring-boot-starter-jdbc</artifactId>
????????</dependency>

????????<dependency>
????????????<groupId>org.projectlombok</groupId>
????????????<artifactId>lombok</artifactId>
????????????<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.springframework.boot</groupId>
????????????<artifactId>spring-boot-starter-web</artifactId>
????????</dependency>
????????<!--druid?的數據源-->
????????<dependency>
????????????<groupId>com.alibaba</groupId>
????????????<artifactId>druid</artifactId>
????????????<version>1.0.5</version>
????????</dependency>
????????<dependency>
????????????<groupId>org.mybatis.spring.boot</groupId>
????????????<artifactId>mybatis-spring-boot-starter</artifactId>
????????????<version>1.3.1</version>
????????</dependency>
????</dependencies>

????<build>
????????<plugins>
????????????<plugin>
????????????????<groupId>org.springframework.boot</groupId>
????????????????<artifactId>spring-boot-maven-plugin</artifactId>
????????????</plugin>
????????????<plugin>
????????????????<artifactId>maven-deploy-plugin</artifactId>
????????????????<version>2.8.2</version>
????????????</plugin>
????????????<plugin>
????????????????<groupId>org.mybatis.generator</groupId>
????????????????<artifactId>mybatis-generator-maven-plugin</artifactId>
????????????????<version>1.3.2</version>
????????????????<dependencies>
????????????????????<dependency>
????????????????????????<groupId>org.mybatis.generator</groupId>
????????????????????????<artifactId>mybatis-generator-core</artifactId>
????????????????????????<version>1.3.5</version>
????????????????????</dependency>
????????????????????<dependency>
????????????????????????<groupId>mysql</groupId>
????????????????????????<artifactId>mysql-connector-java</artifactId>
????????????????????????<version>5.1.41</version>
????????????????????</dependency>
????????????????</dependencies>
????????????????<executions>
????????????????????<execution>
????????????????????????<id>mybatis?generator</id>
????????????????????????<phase>package</phase>
????????????????????????<goals>
????????????????????????????<goal>generate</goal>
????????????????????????</goals>
????????????????????</execution>
????????????????</executions>
????????????????<configuration>
????????????????????<!--?允許移動生成的文件?-->
????????????????????<verbose>true</verbose>
????????????????????<!--?允許自動覆蓋文件?-->
????????????????????<overwrite>true</overwrite>
????????????????????<configurationFile>
????????????????????????src/main/resources/mybatis-generator.xml
????????????????????</configurationFile>
????????????????</configuration>
????????????</plugin>
????????</plugins>
????</build>

</project>

貼上配置文件看看，properties或者yml