Spring IoC踩坑之SAXParseException:cvc-elt.1: 找不到元素 “beans” 的声明

代码

app-context-mmp.xml

DeclareSpringComponents.java

public class DeclareSpringComponents {
	public static void main(String[] args) {
		/* 实现了ApplicationContext接口 */
		GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();
		ctx.load("spring/app-context-mmp.xml");
		//ctx.refresh();//一定要写上！！！
		MessageRender render = ctx.getBean("render",MessageRender.class);
		render.render();
		ctx.close();
	}
}

1、SAXParseException:cvc-elt.1: 找不到元素 “beans” 的声明

现在也不知道啥原因！！！

（1）：spring5之后就不再需要写版本号了

参考：https://www.cnblogs.com/caotao0918/p/10053308.html

没解决！！！

（2）：IDE疯了，重启，maven update

IDE是STS4，重启没效果，update没效果，反倒是发现了一个默认版本太低的问题，参考https://blog.csdn.net/wudinaniya/article/details/74389195

没解决！！！

参考：https://blog.csdn.net/guoquanyou/article/details/79003160

实在是崩溃了！！！于是重新写吧！！！

重写一个xml：mmp.xml,内容是一样的。

接下来运行，就是下面这个错，还好，错换了一个：

五月 04, 2019 10:56:04 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [spring/mmp.xml]
Exception in thread "main" java.lang.IllegalStateException: org.springframework.context.support.GenericXmlApplicationContext@41906a77 has not been refreshed yet
	at org.springframework.context.support.AbstractApplicationContext.assertBeanFactoryActive(AbstractApplicationContext.java:1070)
	at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1088)
	at chap03.com.jay.config.DeclareSpringComponents.main(DeclareSpringComponents.java:13)

2、GenericXmlApplicationContext@41906a77 has not been refreshed yet

仔细检查检查代码，发现少了一行：[   ctx.refresh(); ]，加上后再运行，还是报错

Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'render' available

检查代码，发现少了@Service(value="render")的value：【value="render"】

最后运行成功，可爱的hello world！！！

五月 04, 2019 11:00:39 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [spring/mmp.xml]
五月 04, 2019 11:00:39 上午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.GenericXmlApplicationContext@52a86356: startup date [Sat May 04 11:00:39 CST 2019]; root of context hierarchy
Hello World!!!
五月 04, 2019 11:00:40 上午 org.springframework.context.support.AbstractApplicationContext doClose
信息: Closing org.springframework.context.support.GenericXmlApplicationContext@52a86356: startup date [Sat May 04 11:00:39 CST 2019]; root of context hierarchy

最后是完整的代码

接口

//接口MessageProvider 
public interface MessageProvider {
	String getMessage();
}
//接口MessageRender 
public interface MessageRender {
	void render();

	/* MessageProvider是MessageRender的依赖项 */
	void setMessageProvider(MessageProvider provider);
	MessageProvider getMessageProvider();
}

实现类

//HelloWorldMessageProvider  bean
@Component(value="provider")
public class HelloWorldMessageProvider implements MessageProvider{
	@Override
	public String getMessage() {
		return "Hello World!!!";
	}
}
//HelloWorldMessageRender  bean
@Service(value="render")
public class HelloWorldMessageRender implements MessageRender{
	
	public MessageProvider messageProvider;
	@Override
	public void render() {
		if (messageProvider==null) {
			throw new RuntimeException("you must set the property of messageProvider of class"+HelloWorldMessageRender.class.getName());
		}
		System.out.println(messageProvider.getMessage());
	}
	@Override
	@Autowired
	public void setMessageProvider(MessageProvider provider) {
		messageProvider = provider ;//fuck be careful when coding!!!
	}
	@Override
	public MessageProvider getMessageProvider() {
		return this.messageProvider;
	}
}

xml配置：参考上面的mmp.xml

运行类：参考上面DeclareSpringComponents.java，主语修改配置文件名字，并加上ctx.refresh()。

 

总结：

走不通的路，换一条吧。