Spring框架bean错误[关闭]

Question

我正在尝试在 java 中学习 Spring。当我运行第一个程序时，我一开始就卡住了。 我正在尝试调用 Triangle 类的draw 方法。 但我看到很多错误。

在DrawingApp.java 类中，eclipse 显示了一些警告 - (The type XmlBeanFactory is deprecated)。

我正在提供我的实现以及以下错误。

Triangle.java

package org.hemant.spring;

public class Triangle {

public void draw(){
    System.out.println("Triangle drawn");   
 }
}

DrawingApp.java

package org.hemant.spring;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;

public class DrawingApp {

 /**
 * @param args
 */
 public static void main(String[] args) {

    BeanFactory factory = new XmlBeanFactory(new   FileSystemResource("spring.xml"));

    Triangle triangle = (Triangle)factory.getBean("Triangle.class");
    triangle.draw();
    }

}

spring.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE bean PUBLIC "-//SPRING//DTD BEAN 2.0//EN"     "http://www.springframework.org/dtd/spring-bean-2.0.dtd">

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

错误

     Apr 16, 2016 12:33:45 PM     org.springframework.beans.factory.xml.XmlBeanDefinitionReader    loadBeanDefinitions
    INFO: Loading XML bean definitions from file  [C:\Users\hemant001\workspace_mars_eclipse\spring tutorial\spring.xml]
Exception in thread "main"   org.springframework.beans.factory.BeanDefinitionStoreException: IOException  parsing XML document from file [C:\Users\hemant001\workspace_mars_eclipse\spring  tutorial\spring.xml]; nested exception is java.io.FileNotFoundException:  http://www.springframework.org/dtd/spring-bean-2.0.dtd
at  org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefiniti ons(XmlBeanDefinitionReader.java:408)
at  org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:334)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:302)
at org.springframework.beans.factory.xml.XmlBeanFactory.<init> (XmlBeanFactory.java:78)
at org.springframework.beans.factory.xml.XmlBeanFactory.<init> (XmlBeanFactory.java:66)
at org.hemant.spring.DrawingApp.main(DrawingApp.java:17)
    Caused by: java.io.FileNotFoundException: http://www.springframework.org/dtd/spring-bean-2.0.dtd
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startEntity(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startDTDEntity(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.setInputSource(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(Unknown Source)
at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:75)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:388)
... 5 more

Answer 1

您应该在spring.xml 中将http://www.springframework.org/dtd/spring-bean-2.0.dtd 替换为http://www.springframework.org/dtd/spring-beans-2.0.dtd（注意beans，而不是bean）。

Answer 2

这个：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE bean PUBLIC "-//SPRING//DTD BEAN 2.0//EN"     "http://www.springframework.org/dtd/spring-bean-2.0.dtd">
<bean>
  <bean id="triangle" class="org.hemant.spring.Triangle"/>
</bean>

应该是这样的

<?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.xsd">
      <bean id="triangle" class="org.hemant.spring.Triangle"/>
</beans>

另外，就像 cmets 中提到的那样，factory.getBean("Triangle.class"); 应该是 factory.getBean("triangle");

对于上下文，我宁愿这样做

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

...

        ApplicationContext context = new ClassPathXmlApplicationContext(
                "spring.xml"); // or FileSystemXmlApplicationContext, if .xml is not in class path

        Triangle obj = (Triangle) context.getBean("triangle");

您为什么使用 Spring 2.0 版（基于您的 dtd）？这真的老了。

Answer 3

1. 请不要再使用XmlBeanFactory，使用DefaultListableBeanFactory，因为它将读卡器与工厂分开并代表更干净的OOD。

2. 这不是真正的错误，它是配置的格式问题（我解决这个问题是为了解释为什么 eclipse 不给你消息）。你看，无法读取的配置不是错误。这意味着您的应用程序运行良好（为您的第一次尝试感到自豪），但配置错误！解决doctype和ns的配置丢包问题。

3. Triangle triangle = (Triangle)factory.getBean("Triangle.class"); 找不到定义。请改用Triangle triangle = factory.getBean(Triangle.class);，因为您不必投射。

所以main 应该是这样的：

DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(factory);
reader.loadBeanDefinitions(new FileSystemResource("spring.xml"));
Triangle triangle = factory.getBean(Triangle.class);
triangle.draw();