spring 入门代码调试总是出错

Question

照书上的例子做的，结果运行时总是出以下错误：
Exception in thread "main" java.lang.ExceptionInInitializerError
 at onlyfun.caterpillar.SpringDemo.main(SpringDemo.java:12)
Caused by: java.lang.NullPointerException
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.<clinit>(DefaultListableBeanFactory.java:104)
 ... 1 more
程序代码如下：
HelloBean.java
package onlyfun.caterpillar; 
public class HelloBean { 
    private String helloWord; 
    
    public void setHelloWord(String helloWord) { 
        this.helloWord = helloWord; 
    }     public String getHelloWord() { 
        return helloWord; 
    } 
}
--------------------------------------
SpringDemo.java
package onlyfun.caterpillar; import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.beans.factory.BeanFactory; 
import org.springframework.beans.factory.xml.XmlBeanFactory; public class SpringDemo { 
    public static void main(String[] args) { 
        Resource rs = 
            new ClassPathResource("beans-config.xml"); 
        BeanFactory factory = new XmlBeanFactory(rs); 
        
        HelloBean hello = 
            (HelloBean) factory.getBean("helloBean"); 
        System.out.println(hello.getHelloWord()); 
    } 
}
-----------------------------------------------------
beans-config.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="helloBean" 
          class="onlyfun.caterpillar.HelloBean"> 
        <property name="helloWord">
            <value>Hello!Justin!</value>
        </property> 
    </bean> 
</beans>

Answer 1

照书上的例子做的，结果运行时总是出以下错误：
Exception in thread "main" java.lang.ExceptionInInitializerError
 at onlyfun.caterpillar.SpringDemo.main(SpringDemo.java:12)
Caused by: java.lang.NullPointerException
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.<clinit>(DefaultListableBeanFactory.java:104)
 ... 1 more
程序代码如下：
HelloBean.java
package onlyfun.caterpillar; 
public class HelloBean { 
  private String helloWord; 
   
  public void setHelloWord(String helloWord) { 
  this.helloWord = helloWord; 
  }   public String getHelloWord() { 
  return helloWord; 
  } 
}
--------------------------------------
SpringDemo.java
package onlyfun.caterpillar; import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.beans.factory.BeanFactory; 
import org.springframework.beans.factory.xml.XmlBeanFactory; public class SpringDemo { 
  public static void main(String[] args) { 
  Resource rs = 
  new ClassPathResource("beans-config.xml"); 
  BeanFactory factory = new XmlBeanFactory(rs); 
   
  HelloBean hello = 
  (HelloBean) factory.getBean("helloBean"); 
  System.out.println(hello.getHelloWord()); 
  } 
}
-----------------------------------------------------
beans-config.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="helloBean" 
  class="onlyfun.caterpillar.HelloBean"> 
  <property name="helloWord">
  <value>Hello!Justin!</value>
  </property> 
  </bean> 
</beans>

Answer 2

HelloBean hello =  
  (HelloBean) factory.getBean("helloBean");  
  System.out.println(hello.getHelloWord());  
你的HelloWord没赋值，加一句hello.serHelloWord("dfdfd");

Answer 3

楼主使用下这个new ClassPathResource("beans-config.xml");  写绝对路径看下

Answer 4

楼主看下你的bean，就是哪个HELLO有没有拿到，再测你的里面内容有没拿到

Answer 5

ApplicationContext ac=new ClassPathXmlApplicationContext("beans-config.xml");
HelloBean hello =   
  (HelloBean)ac.getBean("helloBean");
楼主用这个测试下，如果不行再把问题贴出来看看

Answer 6

beans-config.xml  是否在classpath下面。因为没有 xml 解析报错，出现的nullpointexception 应该是发生在获取 beans-config文件出了问题。楼主检查下。

Answer 7

Spring了解甚少，还是了解其基本原理吧，~~