slf4j-Spring MVC测试中的logback NullPointer

Question

下面是相关的pom.xml

     <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>4.2.6-RELEASE</version>
    <exclusions>
      <exclusion>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
      </exclusion>
    </exclusions>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.1.7</version>
</dependency>   
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jcl-over-slf4j</artifactId>
    <version>1.7.21</version>
</dependency>

下面是日志和StackTrace：

20:29:16,293 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Found resource [logback-test.xml] at [file:/code/web/target/test-classes/logback-test.xml]
20:29:16,387 |-ERROR in ch.qos.logback.core.joran.event.SaxEventRecorder@7a1ebcd8 - Unexpected exception while parsing XML document. java.lang.NullPointerException
at java.lang.NullPointerException
at  at org.xml.sax.helpers.LocatorImpl.<init>(LocatorImpl.java:103)
at  at ch.qos.logback.core.joran.event.SaxEvent.<init>(SaxEvent.java:31)
at  at ch.qos.logback.core.joran.event.StartEvent.<init>(StartEvent.java:27)
at  at ch.qos.logback.core.joran.event.SaxEventRecorder.startElement(SaxEventRecorder.java:106)
at  at org.allcolor.xml.parser.CShaniSaxParser.parseStartTag(CShaniSaxParser.java:1393)
at  at org.allcolor.xml.parser.CXmlParser.parseSTARTTag(CXmlParser.java:1405)
at  at org.allcolor.xml.parser.CXmlParser.parse(CXmlParser.java:682)
at  at org.allcolor.xml.parser.CShaniSaxParser.parse(CShaniSaxParser.java:767)
at  at javax.xml.parsers.SAXParser.parse(SAXParser.java:392)
at  at ch.qos.logback.core.joran.event.SaxEventRecorder.recordEvents(SaxEventRecorder.java:59)
at  at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:141)
at  at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:103)
at  at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:53)
at  at ch.qos.logback.classic.util.ContextInitializer.configureByResource(ContextInitializer.java:75)
at  at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:150)
at  at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:84)
at  at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55)
at  at org.slf4j.LoggerFactory.bind(LoggerFactory.java:150)
at  at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:124)
at  at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:412)
at  at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:357)
at  at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:155)
at  at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132)
at  at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:685)
at  at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.<clinit>(SpringJUnit4ClassRunner.java:91)
at  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at  at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at  at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at  at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)

和logback-test.xml：

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <Pattern>.%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg %n
            </Pattern>
        </encoder>
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <level>TRACE</level>
        </filter>
    </appender>
    <root>
        <level value="INFO" />
        <appender-ref ref="consoleAppender" />
    </root> 
    <logger name="com.me.ControllerTester" level="debug" additivity="false">
        <appender-ref ref="consoleAppender" />
    </logger>
</configuration>

Answer 1

日志使用SAXParserFactory.newInstance()，它有一个查找过程，用于确定使用哪个实现。在您的环境中，似乎正在根据以下查找选择org.allcolor.xml.parser.cshanisaxparser:

公共静态SAXParserFactory newInstance()

获取SAXParserFactory的新实例。此静态方法创建一个新的工厂实例此方法使用以下有序查找过程确定要加载的SAXParserFactory实现类：

null

设置jaxp.debugsystem属性将导致该方法向system.err打印大量调试消息，说明它正在执行什么操作以及正在查看什么位置。

如果加载DocumentBuilders时遇到问题，请尝试：

java-djaxp.debug=1您的程序....

-Djavax.xml.parsers.SAXParserFactory=org.apache.xerces.jaxp.SAXParserFactoryImpl