无法在 Eclipse 中运行 Spring Boot 项目

Question

I am trying to learn eclipse for a Java project. I used initializer( https://start.spring.io/ ) to set up Spring Boot using a dependency of spring web. I try to build my project in eclipse and I get the following error

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.5.2)


2021-07-05 12:20:50.248  INFO 23536 --- [           main] o.s.boot.SpringApplication               : Starting SpringApplication v2.5.2 using Java 11.0.2 on MSI with PID 23536 (C:\Users\user\.m2\repository\org\springframework\boot\spring-boot\2.5.2\spring-boot-2.5.2.jar started by user in C:\Users\user\Downloads\app)
2021-07-05 12:20:50.252  INFO 23536 --- [           main] o.s.boot.SpringApplication               : No active profile set, falling back to default profiles: default
2021-07-05 12:20:50.445 ERROR 23536 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalArgumentException: Sources must not be empty
    at org.springframework.util.Assert.notEmpty(Assert.java:470) ~[spring-core-5.3.8.jar:5.3.8]
    at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:425) ~[spring-boot-2.5.2.jar:2.5.2]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:337) ~[spring-boot-2.5.2.jar:2.5.2]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) ~[spring-boot-2.5.2.jar:2.5.2]
    at org.springframework.boot.SpringApplication.main(SpringApplication.java:1359) ~[spring-boot-2.5.2.jar:2.5.2]

Any ideas?

Answer 1

Maybe you're running the wrong class. Run the class which is annotated with @SpringBootApplication

Answer 2

This exact exception and stack trace is thrown in SpringApplication (as of version 2.5.2) when no sources ( Class<?>... ) were provided. This happens when called directly or with the SpringApplicationBuilder like this:

public static void main(String[] args) {
    new SpringApplicationBuilder()
            .registerShutdownHook(true)
            .run(args);
}
// or
public static void main(String[] args) {
    new SpringApplication().run(args);
}

To fix this, pass your class to the builder (eg DemoApplication.class ) like this:

public static void main(String[] args) {
    new SpringApplicationBuilder(DemoApplication.class)
            .registerShutdownHook(true)
            .run(args);
}
// or
public static void main(String[] args) {
    new SpringApplication(DemoApplication.class).run(args);
}

Another option would be to run your application with the static helper method like this:

public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
}