Mybatis连接数据库异常

本人在学习java Web开发，新手入门。请高手解答，谢谢

在之前调试的时候没有问题，在添加一部分代码后在原本没有出现问题的地方报null,代码看不出哪里出错。

数据库是mysql

下面是报错的详细：

java.lang.NullPointerException
	at org.hjava.ec_Shop.util.SqlSessionFactoryUtil.getSqlSession(SqlSessionFactoryUtil.java:35)
	at org.hjava.ec_Shop.service.impl.ArticleServiceImpl.getAllArticles(ArticleServiceImpl.java:21)
	at org.hjava.ec_Shop.action.ArticleAction.articleIndex(ArticleAction.java:27)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:873)
	at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1539)
	at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
	at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:96)
	at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:88)
	at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1615)
	at ognl.ASTMethod.getValueBody(ASTMethod.java:91)
	at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
	at ognl.SimpleNode.getValue(SimpleNode.java:258)
	at ognl.Ognl.getValue(Ognl.java:470)
	at ognl.Ognl.getValue(Ognl.java:434)
	at com.opensymphony.xwork2.ognl.OgnlUtil$3.execute(OgnlUtil.java:351)
	at com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecuteMethod(OgnlUtil.java:403)
	at com.opensymphony.xwork2.ognl.OgnlUtil.callMethod(OgnlUtil.java:349)
	at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:436)
	at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:291)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:252)
	at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:253)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:177)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:260)
	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:73)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.doIntercept(ConversionErrorInterceptor.java:139)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:133)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:133)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:192)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:69)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:115)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:88)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:246)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:139)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:155)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:174)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:120)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:171)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:195)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:193)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:247)
	at org.apache.struts2.factory.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)
	at org.apache.struts2.dispatcher.ExecuteOperations.executeAction(ExecuteOperations.java:81)
	at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:143)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:521)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Unknown Source)
14:26:55.239 [http-nio-80-exec-3] ERROR org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler - Exception occurred during processing request: java.lang.NullPointerException

下面是SqlSessionFactoryUtil 的代码

public class SqlSessionFactoryUtil {

	private static SqlSessionFactory factory;
	private static String resource = "mybatis-config.xml";
	
	static {
		//通过读取mybatis-config.xml文件加载连接池
		try (InputStream inputStream = Resources.getResourceAsStream(resource);) {


			factory = new SqlSessionFactoryBuilder().build(inputStream);
			

		} catch (Exception e) {
			// TODO: handle exception
		}

	}

	//获取连接
	public static SqlSession getSqlSession() {


		return factory.openSession();
	}


	//获取工厂
	public static SqlSessionFactory getFactory() {


		return factory;
	}

ArticleServiceImpl的代码：

public class ArticleServiceImpl implements ArticleService {


	
	@Override
	public List
 getAllArticles() {
		// TODO Auto-generated method stub
		
		//获取数据库连接
		SqlSession session = SqlSessionFactoryUtil.getSqlSession();
		//获取持久层mapper
		ArticleMapper mapper = session.getMapper(ArticleMapper.class);
		//获取查询结果
		List
 articles = mapper.findAllArticles();
		
/*		for (Article article : articles) {
			
			System.out.println(article.getTitle());
			System.out.println(article.getPrice());


		}	*/	
		session.close();
		
		return articles;
	}

Action的代码:

public class ArticleAction extends ActionSupport {


	private static final long serialVersionUID = 1L;
	private ArticleService service = new ArticleServiceImpl();
	private ArticleTypeService articleTypeService=new ArticleTypeServiceImpl();
	
	private List
 articles;
	private List articleTypes;
	
	//获取所有商品信息
	public String articleIndex() throws Exception {
		// TODO Auto-generated method stub


		articles = service.getAllArticles();
		System.out.println("商品数目 ："+articles.size());
		
		articleTypes =articleTypeService.getAllArticleTypes();
		
		return "success";
	}

	public List
 getArticles() {
		return articles;
	}

	public List getArticleTypes() {
		return articleTypes;
	}
	
}

下面是Mybatis配置文件的代码:

properties文件:

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ec_shop
username=root
password=123456

被搞懵了，请dalao们找问题