服务器错误：选择不包含可在服务器上运行的任何资源

Question

我正在尝试使用AOP技术学习Spring框架。为此，我创建了一个普通的Java项目（没有Maven）并导入了弹簧罐spring以及AOP AspectJ的罐子（请参阅下面的屏幕截图）。

之前一切正常，我得到了输出Circle name。

但是第二天我又尝试再次运行该项目，但是我收到窗口错误The selection did not contain any resource that can run on a server。因此，如果我右键单击AopMain类，则在出现错误后，我无法在服务器上运行该类。要再次获得该选项，我必须重新启动eclipse并启动Tomcat 7服务器。

我该怎么做才能解决错误？

AopMain

package org.stack;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.stack.service.ShapeService;


    public class AopMain {
        public static void main(String[] args) {
            ApplicationContext ctx = new ClassPathXmlApplicationContext(
                    "file:src/spring.xml");
            ShapeService shapeService =  (ShapeService) ctx
                    .getBean("shapeService", ShapeService.class);
            System.out.println(shapeService.getCircle().getName());
        }

    }

环

package org.stack.model;

public class Circle {

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

三角

package org.stack.model;

public class Triangle {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

ShapeService

package org.stack.service;

import org.stack.model.Circle;
import org.stack.model.Triangle;

public class ShapeService {
    private Circle circle;
    private Triangle triangle;

    public Circle getCircle() {
        return circle;
    }

    public void setCircle(Circle circle) {
        this.circle = circle;
    }

    public Triangle getTriangle() {
        return triangle;
    }

    public void setTriangle(Triangle triangle) {
        this.triangle = triangle;
    }

}

Spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">

    <aop:aspectj-autoproxy />
    <bean name="triangle" class="org.stack.model.Triangle">
        <property name="name" value="Triangle name"></property>
    </bean>

    <bean name="circle" class="org.stack.model.Circle">
        <property name="name" value="Circle name"></property>
    </bean>

    <bean name="shapeService" class="org.stack.service.ShapeService"
        autowire="byName">
    </bean>

    <!--  <bean name="loggingAspect" class="org.stack.aspect.LoggindAdvice"></bean> -->

</beans>

错误