我是Spring的新手，我必须创建一个“ HelloWorld”应用程序。经过几次尝试，我无法解决我的问题。
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class CiaoMondoApplication {
public static void main(String[] args) {
SpringApplication.run(CiaoMondoApplication.class, args);
}
} // that's the Application
package com.example.demo;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;
@RestController
public class CiaoMondoController {
@RequestMapping("/")
public String index() {
return "HelloWorld";
}
} // and that's the controller
当我尝试使用Eclipse运行应用程序时，在输出下面：
2019-06-11 11:09:33.089 INFO 9572 --- [ main] com.example.demo.CiaoMondoApplication : Starting CiaoMondoApplication on Asus-Mattia with PID 9572 (C:\Users\matti\eclipse-workspace\ciao-mondo\target\classes started by matti in C:\Users\matti\eclipse-workspace\ciao-mondo)
2019-06-11 11:09:33.091 INFO 9572 --- [ main] com.example.demo.CiaoMondoApplication : No active profile set, falling back to default profiles: default
2019-06-11 11:09:33.627 INFO 9572 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data repositories in DEFAULT mode.
2019-06-11 11:09:33.644 INFO 9572 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 11ms. Found 0 repository interfaces.
2019-06-11 11:09:33.895 INFO 9572 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$bb774f16] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2019-06-11 11:09:34.107 INFO 9572 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2019-06-11 11:09:34.127 INFO 9572 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-06-11 11:09:34.127 INFO 9572 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.19]
2019-06-11 11:09:34.219 INFO 9572 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-06-11 11:09:34.219 INFO 9572 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1094 ms
2019-06-11 11:09:34.271 WARN 9572 --- [ main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
2019-06-11 11:09:34.274 INFO 9572 --- [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat]
2019-06-11 11:09:34.284 INFO 9572 --- [ main] ConditionEvaluationReportLoggingListener :
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-06-11 11:09:34.289 ERROR 9572 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter :
***************************
APPLICATION FAILED TO START
***************************
Description:
Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be 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).
答案 0 :(得分：1)
您具有数据启动依赖性，但未添加H2驱动程序，或者您想使用其他数据库，则必须至少添加：url，用户名，密码
如果您不想使用数据库，请从maven或gradle项目文件中删除启动器。
答案 1 :(得分：0)
您可能在下面提到了依赖性
compile group: 'org.springframework.boot', name: 'spring-boot-starter-data-jpa'
因此，Spring将在application.properties中查找数据源url，因此请将其删除，或者如果您要使用jdbc，请在application.properties中添加属性
spring.datasource.url = <jdbc-url>
spring.datasource.username = <db-username>
spring.datasource.password = <db-password>
spring.datasource.driverClassName = <db-driver>
答案 2 :(得分：-1)
如果您在应用程序中不使用任何数据源，则可以在CiaoMondoApplication类上添加以下注释
@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class})
答案 3 :(得分：-2)
/ * *西蒙，你好 * *几个问题，您是否使用过Spring Initializr来构建项目，或者*从头开始了吗？ * * https://start.spring.io/ * *是一个很好的起点： * *这是我的基本应用程序（调用sendgrid api），但这并不重要。 * * /
// Rest Application
package com.XXXXXXX.restapi;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class RestApiApplication{
public static void main(String[] args)
{
SpringApplication.run(RestApiApplication.class, args);
}
}
这就是我的restapi.java中的全部内容
然后我有一个控制器
sendgridcontroller.java
import java.io.IOException;
@RestController
@RequestMapping(sendGridController.BASE_URL)
public class sendGridController
{
public static final String BASE_URL = "/api/v1/feedbacks";
private final sendGridAPI sendGridAPIService;
public sendGridController(sendGridAPIImpl sendGridAPIService)
{
this.sendGridAPIService = sendGridAPIService;
}
@CrossOrigin
@PostMapping("/sendfeedback")
public ResponseEntity<Boolean> sendFeedback(@RequestParam(name="fullname")String fullName,
@RequestParam(name="subject")String subject,
@RequestParam(name="email") String emailAddr,
@RequestParam(name="message")String message )
{
Boolean bReturn = true;
System.out.println("fullName ="+fullName);
System.out.println("subject ="+subject);
System.out.println("email ="+emailAddr);
System.out.println("message ="+message);
try
{
sendGridAPIService.sendFeedbackEmail(fullName, subject, emailAddr, message);
}
catch(Exception e)
{
return new ResponseEntity<>(false,HttpStatus.BAD_GATEWAY);
}
return new ResponseEntity<>(bReturn, HttpStatus.OK);
}
}
这是在自己的程序包中
接下来，我创建了一个包含两个文件的服务包
一个接口sendGridApi.java
package com.ea_optimised.restapi.services;
import org.springframework.stereotype.Service;
import java.io.IOException;
public interface sendGridAPI
{
void sendFeedbackEmail(String fullNameme, String subject, String emailAddr, String message) throws IOException;
}
// ....最后，我实现了该接口
package com.XXXXX.restapi.services;
import com.sendgrid.*;
import org.springframework.stereotype.Service;
import java.io.IOException;
import java.net.UnknownHostException;
import java.rmi.ServerException;
@Service
public class sendGridAPIImpl implements sendGridAPI
{
// API_KEY
private static final String SENDGRID_API_KEY = "My key went here";
@Override
public void sendFeedbackEmail(String fullNameme, String subject, String emailAddr, String message) throws IOException
{
Email from = new Email(emailAddr);
Email to = new Email("info@ea-optimised.co.uk");
// Email to = new Email("test@example.com");
Content content = new Content("text/plain", message);
Mail mail = new Mail(from, subject, to, content);
SendGrid sg = new SendGrid(SENDGRID_API_KEY);
Request request = new Request();
try
{
request.setMethod(Method.POST);
request.setEndpoint("mail/send");
request.setBody(mail.build());
Response response = sg.api(request);
System.out.println("****\nSTATUS="+response.getStatusCode());
System.out.println("\n***Body :\n\n"+response.getBody());
System.out.println("***Headers:\n\n"+response.getHeaders());
}
catch ( UnknownHostException e )
{
System.out.println("***Unknown Host Exception:\n\n");
throw e;
}
catch (Exception ex)
{
System.out.println( "SendGrid Failed "+ex.getMessage());
try
{
throw ex;
}
catch (IOException e)
{
e.printStackTrace();
throw e;
}
}
}
}
希望这会有所帮助
最后要使用Gradle或Maven吗？