这是我的主要应用代码：

package u.d.dip.rs.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;

@EnableWebSecurity
@SpringBootApplication
@ComponentScan(basePackages = "u.d.dip")
@EnableAutoConfiguration
public class DipApplication {
    public static void main(String[] args) {
        SpringApplication.run(DipApplication.class, args);
    }
}

我正在使用gradle构建项目。即使SpringApplication文件已正确导入，我也会收到以下错误：

Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 6 more

Process finished with exit code 1

当我将鼠标悬停在SpringApplication上时，我收到了以下gradle消息

[Gradle: org.springframework.boot:spring-boot:1.5.1.RELEASE] org.springframework.boot public class SpringApplication extends Object

任何帮助将非常感激。提前致谢！