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，它卡在了：

“信息：至少有一个 JAR 已扫描 TLD，但未包含 TLD。为此记录器启用调试日志记录，以获取已扫描但未在其中找到 TLD 的 JAR 的完整列表。在扫描期间跳过不需要的 JAR 可以改善启动时间和 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：

     # Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
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# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

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。

原文由 Coder ACJHP 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

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。然而，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。放：

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

并将打印的罐子名称（不带路径）添加到 tomcat.util.scan.StandardJarScanFilter.jarsToSkip=... 在 tomcat_dir/conf/catalina.properties

原文由 Svetlin Zarev 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

不必将日志记录设置为 FINE、FINEST 或 ALL 以查找要排除的所有 jar。

这是一个脚本，可以找到所有不包含 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 中有可能通过更改（在 catalina.properties 中）排除所有 jar：

 tomcat.util.scan.StandardJarScanFilter.jarsToSkip=\

到

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

（在下面的行中注释掉列表）然后通过更改覆盖包含 TLD 的罐子的决定：

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

并添加通过修改上面的脚本获得的列表，以列出包含 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

原文由 Serafim 发布，翻译遵循 CC BY-SA 3.0 许可协议