无法使用Spring Boot创建mysql数据库

Question

我试图实现没有像h2和derby这样的嵌入式数据库的Spring Boot，而是使用mysql。我不断收到未知的数据库错误。

的pom.xml：

<parent> 
    <groupId>org.springframework.boot</groupId> 
    <artifactId>spring-boot-starter-parent</artifactId> 
    <version>1.5.2.RELEASE</version> 
    <relativePath/> <!-- lookup parent from repository --> 
</parent> 

<properties> 
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> 
    <java.version>1.8</java.version> 
</properties> 

<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>com.h2database</groupId> 
      <artifactId>h2</artifactId> 
      <scope>runtime</scope> 
    </dependency>--> 
    <dependency> 
     <groupId>mysql</groupId> 
     <artifactId>mysql-connector-java</artifactId> 
     <version>5.1.38</version> 
    </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> 

application.properties：

#Database Configuration 
spring.datasource.url=jdbc:mysql://localhost:3306/sampleDB 
spring.datasource.username=root 
spring.datasource.password=root 
spring.datasource.driverClassName=com.mysql.jdbc.Driver 
spring.jpa.generate-ddl=true 
spring.jpa.hibernate.ddl-auto=update 
spring.jpa.show-sql=true 

错误：

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown database 'sampledb' 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111] 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_111] 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_111] 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_111] 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.Util.getInstance(Util.java:387) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:939) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1694) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1215) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2255) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2286) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2085) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44) ~[mysql-connector-java-5.1.38.jar:5.1.38] 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111] 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_111] 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_111] 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_111] 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) ~[mysql-connector-java-5.1.38.jar:5.1.38] 

如果我使用像提到H2则没有工作的任何一个嵌入式数据库在application.properties文件中，但如果我使用MySQL，则会出现此错误。请帮忙。

Answer 1

您连接到数据库sampleDB这不是由mysql自动创建的，与h2不同。

你必须自己使用mysql -u <user> -p -e "create database sampleDB"

Answer 2

您需要先创建数据库创建它。