Question

我刚刚开始使用spring框架并尝试了这个site的“Hello world”教程。我有 Mainapp.Java 为

package com.springdemo;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainApp {
    public static void main(String[] args) {
        ApplicationContext context =new ClassPathXmlApplicationContext("bean.xml");
        Hello_World obj = (Hello_World)context.getBean("helloworld");
        obj.getMessage();
        }
}

Hello_World.java

package com.springdemo;

public class Hello_World {

    private String message;
    public void setMessage(String message){
    this.message = message;
    }
    public void getMessage(){
    System.out.println("Your Message : " + message);
    }
}

和 bean.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
<bean id="helloworld" class="com.springdemo">
<property name="message" value="Hello World!"/>
</bean>
</beans>

错误

Exception in thread "main" org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [com.springdemo] for bean with name 'helloworld' defined in class path resource [bean.xml]; nested exception is java.lang.ClassNotFoundException: com.springdemo
    at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1173)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:479)
    at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:787)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:393)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:736)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:369)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:123)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:66)
    at com.springdemo.MainApp.main(MainApp.java:8)
Caused by: java.lang.ClassNotFoundException: com.springdemo
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at org.springframework.util.ClassUtils.forName(ClassUtils.java:230)
    at org.springframework.beans.factory.support.AbstractBeanDefinition.resolveBeanClass(AbstractBeanDefinition.java:381)
    at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1170)
    ... 8 more

Answer 1

当然@ c.P.u1已经给出了你可以尝试的其他出路（自动检测）的答案

删除显式bean声明
使用Hello_World

@Component

在配置文件中使用<annotation-driven />
使用<context:component-scan base-package="com.springdemo" />

Answer 2

谢谢。我有同样的错误。我在xml文件中给出了像org.stuff.Triangle.Java这样的完整类名而不是

这是我的代码的正确方法

        <bean id="triangle" class="org.stuff.Triangle"/>

Answer 3

更新bean.xml

<bean id="helloworld" class="com.springdemo.Hello_World">
    <property name="message" value="Hello World!"/>
</bean>

Answer 4

确保在bean.xml中添加类位置对于您的情况，Hello_World类是返回值的类，因此只需调用此类。

<bean id="helloworld" class="com.springdemo.Hello_World">
   <property name="message" value="Hello World!"/>
</bean>

我在你的代码中注意到了另外一件事。在主类中，您必须编写getBean（Bean ID值）

所以我认为正确的应该是：

Hello_World message= (Hello_World)appContext.getBean("helloworld");

Answer 5

在bean标记中，类参数应包含完整的类名路径。您尚未编写类名。代替这个 bean id =“ helloworld” class =“ com.springdemo”

写这个 bean id =“ helloworld” class =“ com.springdemo.Hello_World”

无法在类路径资源[bean.xml]中定义名为'helloworld'的bean找到类[com.springdemo]

5 个答案: