如何在 Tomcat 9.0.0M10 中修复“已扫描但未在其中找到 TLD 的 JAR”

Question

我是 Java EE 的新手，正在尝试使用 ServletContextListener 并且侦听器工作是连接到数据库 bla bla 。当我尝试启动服务器（Tomcat 9）时，它卡住了：

“信息：至少有一个 JAR 已扫描 TLD，但未包含 TLD。 启用此记录器的调试日志记录以获取完整的 JAR 列表 已扫描但未在其中找到 TLD。跳过不需要的 JAR 在扫描期间可以提高启动时间和 JSP 编译时间。”

所以我更改了“日志记录属性文件”中的一些属性，如下所示：

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handlers = 1catalina.org.apache.juli.AsyncFileHandler, 2localhost.org.apache.juli.AsyncFileHandler, 3manager.org.apache.juli.AsyncFileHandler, 4host-manager.org.apache.juli.AsyncFileHandler, java.util.logging.ConsoleHandler

.handlers = 1catalina.org.apache.juli.AsyncFileHandler, java.util.logging.ConsoleHandler

############################################################
# Handler specific properties.
# Describes specific configuration info for Handlers.
############################################################

1catalina.org.apache.juli.AsyncFileHandler.level = FINE
1catalina.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
1catalina.org.apache.juli.AsyncFileHandler.prefix = catalina.

2localhost.org.apache.juli.AsyncFileHandler.level = FINE
2localhost.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
2localhost.org.apache.juli.AsyncFileHandler.prefix = localhost.

3manager.org.apache.juli.AsyncFileHandler.level = FINE
3manager.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
3manager.org.apache.juli.AsyncFileHandler.prefix = manager.

4host-manager.org.apache.juli.AsyncFileHandler.level = FINE
4host-manager.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
4host-manager.org.apache.juli.AsyncFileHandler.prefix = host-manager.

java.util.logging.ConsoleHandler.level = FINE
java.util.logging.ConsoleHandler.formatter = org.apache.juli.OneLineFormatter


############################################################
# Facility specific properties.
# Provides extra control for each logger.
############################################################

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = FINE
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].handlers = 2localhost.org.apache.juli.AsyncFileHandler

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].level = FINE
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].handlers = 3manager.org.apache.juli.AsyncFileHandler

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager].level = FINE
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager].handlers = 4host-manager.org.apache.juli.AsyncFileHandler

# For example, set the org.apache.catalina.util.LifecycleBase logger to log
# each component that extends LifecycleBase changing state:
#org.apache.catalina.util.LifecycleBase.level = FINE

# To see debug messages in TldLocationsCache, uncomment the following line:
org.apache.jasper.compiler.TldLocationsCache.level = FINE
org.apache.jasper.servlet.TldScanner.level = FINE

# To see debug messages for HTTP/2 handling, uncomment the following line:
#org.apache.coyote.http2.level = FINE

# To see debug messages for WebSocket handling, uncomment the following line:
#org.apache.tomcat.websocket.level = FINE

所有答案都可以接受。谢谢大家。

Answer 1

更改 conf\context.xml 文件

<Context>
    <!-- only if you do not use jsp tag -->
    <JarScanner>
        <JarScanFilter defaultPluggabilityScan="false" defaultTldScan="false"/>
    </JarScanner>
</Context>

见：https://tomcat.apache.org/tomcat-9.0-doc/config/jar-scan-filter.html

Answer 2

我解决了同样的问题.. 我认为这有权限问题，因此需要为 webapps/project 文件夹提供完全访问权限。

Answer 3

不需要将日志记录设置为 FINE、FINEST 或 ALL 来查找所有要排除的 jar。

这是一个脚本，用于查找所有不包含 TLD 的 jar（更改 TOMCAT_HOME 变量以匹配您的安装）并在表单上输出一个列表

jar1.jar,\
jar2.jar,\
...

可以粘贴到 catalina.properties 中（省略最后一个 ',\'）：

#!/bin/sh
TOMCAT_HOME=/opt/tomcat
for i in `find $TOMCAT_HOME -follow -name "*jar"`
do
    jar tvf $i | grep -i tld > /dev/null
    if [ $? -ne 0 ]; then
        echo "$(basename $i),\\"
    fi
done

但是，如果我被正确告知，tomcat 9 有可能通过更改（在 catalina.properties 中）来排除所有 jar：

tomcat.util.scan.StandardJarScanFilter.jarsToSkip=\

到

tomcat.util.scan.StandardJarScanFilter.jarsToSkip=*.jar

（注释掉下面行中的列表）然后通过更改覆盖包含 TLD 的 jar 的决定：

tomcat.util.scan.StandardJarScanFilter.jarsToScan=\
log4j-web*.jar,log4j-taglib*.jar,log4javascript*.jar,slf4j-taglib*.jar

并添加通过修改上述脚本获得的列表以列出确实包含 TLD 的 jar：

#!/bin/sh
TOMCAT_HOME=/opt/tomcat
for i in `find $TOMCAT_HOME -follow -name "*jar"`
do
    jar tvf $i | grep -i tld > /dev/null
    if [ $? -eq 0 ]; then
        echo "$(basename $i),\\"
    fi
done

Answer 4

这不是 tomcat 中的错误或任何类型的问题。 Tomcat 只是通知您存在不包含 TLD 的 jar，您可以将它们添加到扫描仪的跳过列表中以提高启动性能。所以你有两个选择：

1. 您可以放心地忽略该提示。但是，如果它惹恼了您，您可以将该特定记录器设置为更高的记录级别，从而防止 tomcat 记录它。只需将org.apache.jasper.servlet.TldScanner.level = SEVERE 添加到logging.properties 的末尾即可。

2. 启用调试日志以使 tomcat 列出这些 jar 并将它们添加到跳过列表中。设置：

   org.apache.jasper.compiler.TldLocationsCache.level = FINE
   org.apache.jasper.servlet.TldScanner.level = FINE
   

并将打印的 jar 名称（不包括路径）添加到 tomcat_dir/conf/catalina.properties 中的tomcat.util.scan.StandardJarScanFilter.jarsToSkip=...