Java 如何修复 Tomcat 9.0.0M10 中的“已扫描但未在其中找到 TLD 的 JAR”

How to fix "JARs that were scanned but no TLDs were found in them " in Tomcat 9.0.0M10

提问by Coder ACJHP

I'm new to Java EE and trying to work on ServletContextListener and listener job is connection to database bla bla .When I am trying to start the server (Tomcat 9) it is stuck on :

我是 Java EE 的新手，并试图在 ServletContextListener 上工作，侦听器的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：

"INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time."

“信息：至少扫描了一个 JAR 以查找 TLD，但不包含 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。”

So I changed some properties in "Logging properties file" like this :

所以我在“日志属性文件”中更改了一些属性，如下所示：

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# 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
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# distributed under the License is distributed on an "AS IS" BASIS,
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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

All answers acceptable.Thanks for all.

所有答案都可以接受。谢谢大家。

采纳答案by Svetlin Zarev

This is not a bug or any kind of problem in tomcat. Tomcat is just informing you that there are jars that do not contain TLDs and you can add them to the scanner's skip list to improve startup performance. So you have two options:

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器的跳过列表中以提高启动性能。所以你有两个选择：

1. You can safely ignore that hint. Yet if it annoy you, you can set that specific logger to a higher logging level, and thus prevent tomcat from logging it. Just add org.apache.jasper.servlet.TldScanner.level = SEVEREto the end of logging.properties.

2. Enable the debug logging to make tomcat list those jars and add them to the skip list. Set:

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

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日志记录级别，从而防止 tomcat 对其进行记录。只需添加org.apache.jasper.servlet.TldScanner.level = SEVERE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
   

And add the printed jars names (without the path) to tomcat.util.scan.StandardJarScanFilter.jarsToSkip=...in tomcat_dir/conf/catalina.properties

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

回答by Serafim Dahl

Setting the logging to FINE, FINEST or ALL to find all jars to exclude is not neccessary.

不需要将日志记录设置为 FINE、FINEST 或 ALL 来查找要排除的所有 jars。

Here is a script that finds all jars not containing TLDs (change the TOMCAT_HOME variable to match your installation) and outputs a list on the form

这是一个脚本，它查找所有不包含 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,\
...

that can be pasted into catalina.properties (omit the last ',\'):

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

However, if I am correctly informed, there is a possibility in tomcat 9 to exclude all jars by changing (in catalina.properties):

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

tomcat.util.scan.StandardJarScanFilter.jarsToSkip=\

to

到

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

(comment away the list on the lines below) and then override that decision for jars containg TLDs by changing:

（注释掉下面几行的列表）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

and add the list obtained by modifying the script above to list the jars that do contain TLDs:

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

回答by Bala Murugan

same problem i was fixed.. I think this have permission problem, so need to give full access for webapps/project folder.

同样的问题我被修复了..我认为这有权限问题，所以需要给予 webapps/project 文件夹的完全访问权限。

回答by Roc King

change conf\context.xml file

更改 conf\context.xml 文件

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

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

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