Spring boot 如何解决自动配置数据源失败的问题：'；spring.datasource.url'；未指定，并且无法自动配置嵌入式数据源

我正在尝试在EC2中运行SpringBoot应用程序，我已经在RDS中托管了mysql。当我在本地数据库中尝试时，它工作得很好，但当我切换到Rds时，应用程序就给了我错误

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to auto-configure a DataSource: 'spring.datasource.url' is not 
specified and no embedded datasource could be auto-configured.

Reason: Failed to determine a suitable driver class


Action:

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).

我在谷歌上搜索并尝试在应用程序中添加一些配置，但它对我不起作用

在这里，我发布了应用程序提到的类

AppUserDAO

@Repository
@Transactional
public class AppUserDAO {


@Autowired
private EntityManager entityManager;

public AppUser findUserAccount(String userName) {
    try {
        String sql = "Select e from " + AppUser.class.getName() + " e " //
                + " Where e.userName = :userName ";

        Query query = entityManager.createQuery(sql, AppUser.class);
        query.setParameter("userName", userName);

        return (AppUser) query.getSingleResult();
    } catch (NoResultException e) {
        return null;
    }
   }
  }

批准道

@Repository
@Transactional
public class AppRoleDAO {

@Autowired
private EntityManager entityManager;

public List<String> getRoleNames(Long userId) {
    String sql = "Select ur.appRole.roleName from " + UserRole.class.getName() + " ur " //
            + " where ur.appUser.userId = :userId ";

    Query query = this.entityManager.createQuery(sql, String.class);
    query.setParameter("userId", userId);
    return query.getResultList();
    }
 }

pom.xml

      <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 
      http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>org.o7planning</groupId>
      <artifactId>SpringBootSecurityJPA</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <packaging>jar</packaging>

      <name>SpringBootSecurityJPA</name>
      <description>Spring Boot +Spring Security + JPA + Remember 
      Me</description>

      <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.0.0.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-security</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</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-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>


<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
           <mainClass>org.o7planning.sbsecurity.SpringBootSecurityJpaApplication</mainClass>
            </configuration>
        <executions>
            <execution>
                <goals>
                    <goal>repackage</goal>
                </goals>
            </execution>
        </executions>
        </plugin>
    </plugins>
</build>

4.0.0
org.o7planning
SpringBootSecurityJPA
0.0.1-快照
罐子
SpringBootSecurityJPA
Spring Boot+Spring Security+JPA+记住
我
org.springframework.boot
spring启动程序父级
2.0.0.1版本
UTF-8
UTF-8
1.8
org.springframework.boot
spring引导启动器数据jpa
org.springframework.boot
弹簧启动安全
org.springframework.boot
弹簧启动装置
org.springframework.boot
SpringBootStarterWeb
mysql
mysql连接器java
运行时
org.springframework.boot
弹簧起动试验
测试
org.springframework.security
弹簧安全性试验
测试
org.springframework.boot
springbootmaven插件
org.o7planning.sbsecurity.springbootsecurityjpaa应用程序
重新包装

---

请帮助我解决此问题，尝试在DAO中按构造函数而不是字段注入EntityManager依赖项。 此外，您还可以在主Spring Boot应用程序类中初始化bean，如下所示：

@Bean
public EntityManager entityManager() {
      return new EntityManager();
}

试试这个

@PersistenceContext
private EntityManager entityManager;

编辑 经过相关编辑

无法自动配置数据源：“spring.DataSource.url”未指定，无法自动配置嵌入式数据源

原因：无法确定合适的驱动程序类别

您必须在application.properties中提到mysql的驱动程序

spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver

(or)

spring.datasource.driverClassName=com.mysql.jdbc.Driver

---

为什么要排除数据源配置？如果没有数据源，将不会有

EntityManager工厂

，因此也不会有

EntityManager

。遇到同样的问题您可以在应用程序属性中更新MySql驱动程序吗

@PersistenceContext
private EntityManager entityManager;

spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver

(or)

spring.datasource.driverClassName=com.mysql.jdbc.Driver