关于使用apache-tomcat-7.0.67中在apache-tomcat-7.0.67/log/catalina.out文件过大的解决方案
在正式的项目中用到tomcat作为容器，但有个问题apache-tomcat-7.0.67/log/catalina.out该文件会无限的扩大，而且里面记录的都是log4j已经记录的日志，所有apache-tomcat-7.0.67/log/catalina.out记录的日志对项目来说没有多大的意义而且也非常的消耗性能和IO，那么我们有什么办法来避免这个apache-tomcat-7.0.67/log/catalina.out日志过大或者就是不要这个日志输出呢
方案1
可通过修改apache-tomcat-7.0.67/conf/logging.properties日志配置文件来屏蔽掉这部分的日志信息。
1catalina.org.apache.juli.FileHandler.level = FINE
1catalina.org.apache.juli.FileHandler.directory = ${catalina.base}/logs
1catalina.org.apache.juli.FileHandler.prefix = catalina.通过将1catalina.org.apache.juli.FileHandler.level的日志级别设置成 WARNING可以减少输出
一般日志的级别有：
SEVERE (highest value) > WARNING > INFO > CONFIG > FINE > FINER > FINEST (lowest value)
SEVERE (highest value) > WARNING > INFO > CONFIG > FINE > FINER > FINEST (lowest value)
方案2
直接修改apache-tomcat-7.0.67/bin/catalina.sh下面的日志输出
#!/bin/sh
# 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
#
# Unless required by applicable law or agreed to in writing, software
# 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.
# -----------------------------------------------------------------------------
# Control Script for the CATALINA Server
#
# Environment Variable Prerequisites
#
# Do not set the variables in this script. Instead put them into a script
# setenv.sh in CATALINA_BASE/bin to keep your customizations separate.
#
# CATALINA_HOME May point at your Catalina "build" directory.
#
# CATALINA_BASE (Optional) Base directory for resolving dynamic portions
# of a Catalina installation. If not present, resolves to
# the same directory that CATALINA_HOME points to.
#
# CATALINA_OUT (Optional) Full path to a file where stdout and stderr
# will be redirected.
# Default is $CATALINA_BASE/logs/catalina.out
#
# CATALINA_OPTS (Optional) Java runtime options used when the "start",
# "run" or "debug" command is executed.
# Include here and not in JAVA_OPTS all options, that should
# only be used by Tomcat itself, not by the stop process,
# the version command etc.
# Examples are heap size, GC logging, JMX ports etc.
#
# CATALINA_TMPDIR (Optional) Directory path location of temporary directory
# the JVM should use (java.io.tmpdir). Defaults to
# $CATALINA_BASE/temp.
#
# JAVA_HOME Must point at your Java Development Kit installation.
# Required to run the with the "debug" argument.
#
# JRE_HOME Must point at your Java Runtime installation.
# Defaults to JAVA_HOME if empty. If JRE_HOME and JAVA_HOME
# are both set, JRE_HOME is used.
#
# JAVA_OPTS (Optional) Java runtime options used when any command
# is executed.
# Include here and not in CATALINA_OPTS all options, that
# should be used by Tomcat and also by the stop process,
# the version command etc.
# Most options should go into CATALINA_OPTS.
#
# JAVA_ENDORSED_DIRS (Optional) Lists of of colon separated directories
# containing some jars in order to allow replacement of APIs
# created outside of the JCP (i.e. DOM and SAX from W3C).
# It can also be used to update the XML parser implementation.
# Defaults to $CATALINA_HOME/endorsed.
#
# JPDA_TRANSPORT (Optional) JPDA transport used when the "jpda start"
# command is executed. The default is "dt_socket".
#
# JPDA_ADDRESS (Optional) Java runtime options used when the "jpda start"
# command is executed. The default is 8000.
#
# JPDA_SUSPEND (Optional) Java runtime options used when the "jpda start"
# command is executed. Specifies whether JVM should suspend
# execution immediately after startup. Default is "n".
#
# JPDA_OPTS (Optional) Java runtime options used when the "jpda start"
# command is executed. If used, JPDA_TRANSPORT, JPDA_ADDRESS,
# and JPDA_SUSPEND are ignored. Thus, all required jpda
# options MUST be specified. The default is:
#
# -agentlib:jdwp=transport=$JPDA_TRANSPORT,
# address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND
#
# CATALINA_PID (Optional) Path of the file which should contains the pid
# of the catalina startup java process, when start (fork) is
# used
#
# LOGGING_CONFIG (Optional) Override Tomcat's logging config file
# Example (all one line)
# LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"
#
# LOGGING_MANAGER (Optional) Override Tomcat's logging manager
# Example (all one line)
# LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
# -----------------------------------------------------------------------------
# OS specific support. $var _must_ be set to either true or false.
cygwin=false
darwin=false
os400=false
case "`uname`" in
CYGWIN*) cygwin=true;;
Darwin*) darwin=true;;
OS400*) os400=true;;
esac
# resolve links - $0 may be a softlink
PRG="$0"
while [ -h "$PRG" ]; do
ls=`ls -ld "$PRG"`
link=`expr "$ls" : '.*-> \(.*\)$'`
if expr "$link" : '/.*' > /dev/null; then
PRG="$link"
else
PRG=`dirname "$PRG"`/"$link"
fi
done
# Get standard environment variables
PRGDIR=`dirname "$PRG"`
# Only set CATALINA_HOME if not already set
[ -z "$CATALINA_HOME" ] && CATALINA_HOME=`cd "$PRGDIR/.." >/dev/null; pwd`
# Copy CATALINA_BASE from CATALINA_HOME if not already set
[ -z "$CATALINA_BASE" ] && CATALINA_BASE="$CATALINA_HOME"
# Ensure that any user defined CLASSPATH variables are not used on startup,
# but allow them to be specified in setenv.sh, in rare case when it is needed.
CLASSPATH=
if [ -r "$CATALINA_BASE/bin/setenv.sh" ]; then
. "$CATALINA_BASE/bin/setenv.sh"
elif [ -r "$CATALINA_HOME/bin/setenv.sh" ]; then
. "$CATALINA_HOME/bin/setenv.sh"
fi
# For Cygwin, ensure paths are in UNIX format before anything is touched
if $cygwin; then
[ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
[ -n "$JRE_HOME" ] && JRE_HOME=`cygpath --unix "$JRE_HOME"`
[ -n "$CATALINA_HOME" ] && CATALINA_HOME=`cygpath --unix "$CATALINA_HOME"`
[ -n "$CATALINA_BASE" ] && CATALINA_BASE=`cygpath --unix "$CATALINA_BASE"`
[ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
fi
# For OS400
if $os400; then
# Set job priority to standard for interactive (interactive - 6) by using
# the interactive priority - 6, the helper threads that respond to requests
# will be running at the same priority as interactive jobs.
COMMAND='chgjob job('$JOBNAME') runpty(6)'
system $COMMAND
# Enable multi threading
export QIBM_MULTI_THREADED=Y
fi
# Get standard Java environment variables
if $os400; then
# -r will Only work on the os400 if the files are:
# 1. owned by the user
# 2. owned by the PRIMARY group of the user
# this will not work if the user belongs in secondary groups
. "$CATALINA_HOME"/bin/setclasspath.sh
else
if [ -r "$CATALINA_HOME"/bin/setclasspath.sh ]; then
. "$CATALINA_HOME"/bin/setclasspath.sh
else
echo "Cannot find $CATALINA_HOME/bin/setclasspath.sh"
echo "This file is needed to run this program"
exit 1
fi
fi
# Add on extra jar files to CLASSPATH
if [ ! -z "$CLASSPATH" ] ; then
CLASSPATH="$CLASSPATH":
fi
CLASSPATH="$CLASSPATH""$CATALINA_HOME"/bin/bootstrap.jar
if [ -z "$CATALINA_OUT" ] ; then
CATALINA_OUT="$CATALINA_BASE"/logs/catalina.out
fi
if [ -z "$CATALINA_TMPDIR" ] ; then
# Define the java.io.tmpdir to use for Catalina
CATALINA_TMPDIR="$CATALINA_BASE"/temp
fi
# Add tomcat-juli.jar to classpath
# tomcat-juli.jar can be over-ridden per instance
if [ -r "$CATALINA_BASE/bin/tomcat-juli.jar" ] ; then
CLASSPATH=$CLASSPATH:$CATALINA_BASE/bin/tomcat-juli.jar
else
CLASSPATH=$CLASSPATH:$CATALINA_HOME/bin/tomcat-juli.jar
fi
# Bugzilla 37848: When no TTY is available, don't output to console
have_tty=0
if [ "`tty`" != "not a tty" ]; then
have_tty=1
fi
# For Cygwin, switch paths to Windows format before running java
if $cygwin; then
JAVA_HOME=`cygpath --absolute --windows "$JAVA_HOME"`
JRE_HOME=`cygpath --absolute --windows "$JRE_HOME"`
CATALINA_HOME=`cygpath --absolute --windows "$CATALINA_HOME"`
CATALINA_BASE=`cygpath --absolute --windows "$CATALINA_BASE"`
CATALINA_TMPDIR=`cygpath --absolute --windows "$CATALINA_TMPDIR"`
CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
JAVA_ENDORSED_DIRS=`cygpath --path --windows "$JAVA_ENDORSED_DIRS"`
fi
# Set juli LogManager config file if it is present and an override has not been issued
if [ -z "$LOGGING_CONFIG" ]; then
if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then
LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"
else
# Bugzilla 45585
LOGGING_CONFIG="-Dnop"
fi
fi
if [ -z "$LOGGING_MANAGER" ]; then
LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
fi
# Uncomment the following line to make the umask available when using the
# org.apache.catalina.security.SecurityListener
#JAVA_OPTS="$JAVA_OPTS -Dorg.apache.catalina.security.SecurityListener.UMASK=`umask`"
# ----- Execute The Requested Command -----------------------------------------
# Bugzilla 37848: only output this if we have a TTY
if [ $have_tty -eq 1 ]; then
echo "Using CATALINA_BASE: $CATALINA_BASE"
echo "Using CATALINA_HOME: $CATALINA_HOME"
echo "Using CATALINA_TMPDIR: $CATALINA_TMPDIR"
if [ "$1" = "debug" ] ; then
echo "Using JAVA_HOME: $JAVA_HOME"
else
echo "Using JRE_HOME: $JRE_HOME"
fi
echo "Using CLASSPATH: $CLASSPATH"
if [ ! -z "$CATALINA_PID" ]; then
echo "Using CATALINA_PID: $CATALINA_PID"
fi
fi
if [ "$1" = "jpda" ] ; then
if [ -z "$JPDA_TRANSPORT" ]; then
JPDA_TRANSPORT="dt_socket"
fi
if [ -z "$JPDA_ADDRESS" ]; then
JPDA_ADDRESS="8000"
fi
if [ -z "$JPDA_SUSPEND" ]; then
JPDA_SUSPEND="n"
fi
if [ -z "$JPDA_OPTS" ]; then
JPDA_OPTS="-agentlib:jdwp=transport=$JPDA_TRANSPORT,address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND"
fi
CATALINA_OPTS="$JPDA_OPTS $CATALINA_OPTS"
shift
fi
if [ "$1" = "debug" ] ; then
if $os400; then
echo "Debug command not available on OS400"
exit 1
else
shift
if [ "$1" = "-security" ] ; then
if [ $have_tty -eq 1 ]; then
echo "Using Security Manager"
fi
shift
exec "$_RUNJDB" "$LOGGING_CONFIG" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
-sourcepath "$CATALINA_HOME"/../../java \
-Djava.security.manager \
-Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \
-Dcatalina.base="$CATALINA_BASE" \
-Dcatalina.home="$CATALINA_HOME" \
-Djava.io.tmpdir="$CATALINA_TMPDIR" \
org.apache.catalina.startup.Bootstrap "$@" start
else
exec "$_RUNJDB" "$LOGGING_CONFIG" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
-sourcepath "$CATALINA_HOME"/../../java \
-Dcatalina.base="$CATALINA_BASE" \
-Dcatalina.home="$CATALINA_HOME" \
-Djava.io.tmpdir="$CATALINA_TMPDIR" \
org.apache.catalina.startup.Bootstrap "$@" start
fi
fi
elif [ "$1" = "run" ]; then
shift
if [ "$1" = "-security" ] ; then
if [ $have_tty -eq 1 ]; then
echo "Using Security Manager"
fi
shift
eval exec "\"$_RUNJAVA\"" "\"$LOGGING_CONFIG\"" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="\"$JAVA_ENDORSED_DIRS\"" -classpath "\"$CLASSPATH\"" \
-Djava.security.manager \
-Djava.security.policy=="\"$CATALINA_BASE/conf/catalina.policy\"" \
-Dcatalina.base="\"$CATALINA_BASE\"" \
-Dcatalina.home="\"$CATALINA_HOME\"" \
-Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
org.apache.catalina.startup.Bootstrap "$@" start
else
eval exec "\"$_RUNJAVA\"" "\"$LOGGING_CONFIG\"" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="\"$JAVA_ENDORSED_DIRS\"" -classpath "\"$CLASSPATH\"" \
-Dcatalina.base="\"$CATALINA_BASE\"" \
-Dcatalina.home="\"$CATALINA_HOME\"" \
-Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
org.apache.catalina.startup.Bootstrap "$@" start
fi
elif [ "$1" = "start" ] ; then
if [ ! -z "$CATALINA_PID" ]; then
if [ -f "$CATALINA_PID" ]; then
if [ -s "$CATALINA_PID" ]; then
echo "Existing PID file found during start."
if [ -r "$CATALINA_PID" ]; then
PID=`cat "$CATALINA_PID"`
ps -p $PID >/dev/null 2>&1
if [ $? -eq 0 ] ; then
echo "Tomcat appears to still be running with PID $PID. Start aborted."
echo "If the following process is not a Tomcat process, remove the PID file and try again:"
ps -f -p $PID
exit 1
else
echo "Removing/clearing stale PID file."
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ -w "$CATALINA_PID" ]; then
cat /dev/null > "$CATALINA_PID"
else
echo "Unable to remove or clear stale PID file. Start aborted."
exit 1
fi
fi
fi
else
echo "Unable to read PID file. Start aborted."
exit 1
fi
else
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ ! -w "$CATALINA_PID" ]; then
echo "Unable to remove or write to empty PID file. Start aborted."
exit 1
fi
fi
fi
fi
fi
shift
touch "$CATALINA_OUT"
if [ "$1" = "-security" ] ; then
if [ $have_tty -eq 1 ]; then
echo "Using Security Manager"
fi
shift
eval "\"$_RUNJAVA\"" "\"$LOGGING_CONFIG\"" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="\"$JAVA_ENDORSED_DIRS\"" -classpath "\"$CLASSPATH\"" \
-Djava.security.manager \
-Djava.security.policy=="\"$CATALINA_BASE/conf/catalina.policy\"" \
-Dcatalina.base="\"$CATALINA_BASE\"" \
-Dcatalina.home="\"$CATALINA_HOME\"" \
-Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
org.apache.catalina.startup.Bootstrap "$@" start \
>> "$CATALINA_OUT" 2>&1 "&"
else
eval "\"$_RUNJAVA\"" "\"$LOGGING_CONFIG\"" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="\"$JAVA_ENDORSED_DIRS\"" -classpath "\"$CLASSPATH\"" \
-Dcatalina.base="\"$CATALINA_BASE\"" \
-Dcatalina.home="\"$CATALINA_HOME\"" \
-Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
org.apache.catalina.startup.Bootstrap "$@" start \
>> "$CATALINA_OUT" 2>&1 "&"
fi
if [ ! -z "$CATALINA_PID" ]; then
echo $! > "$CATALINA_PID"
fi
echo "Tomcat started."
elif [ "$1" = "stop" ] ; then
shift
SLEEP=5
if [ ! -z "$1" ]; then
echo $1 | grep "[^0-9]" >/dev/null 2>&1
if [ $? -gt 0 ]; then
SLEEP=$1
shift
fi
fi
FORCE=0
if [ "$1" = "-force" ]; then
shift
FORCE=1
fi
if [ ! -z "$CATALINA_PID" ]; then
if [ -f "$CATALINA_PID" ]; then
if [ -s "$CATALINA_PID" ]; then
kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
if [ $? -gt 0 ]; then
echo "PID file found but no matching process was found. Stop aborted."
exit 1
fi
else
echo "PID file is empty and has been ignored."
fi
else
echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted."
exit 1
fi
fi
eval "\"$_RUNJAVA\"" $LOGGING_MANAGER $JAVA_OPTS \
-Djava.endorsed.dirs="\"$JAVA_ENDORSED_DIRS\"" -classpath "\"$CLASSPATH\"" \
-Dcatalina.base="\"$CATALINA_BASE\"" \
-Dcatalina.home="\"$CATALINA_HOME\"" \
-Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
org.apache.catalina.startup.Bootstrap "$@" stop
# stop failed. Shutdown port disabled? Try a normal kill.
if [ $? != 0 ]; then
if [ ! -z "$CATALINA_PID" ]; then
echo "The stop command failed. Attempting to signal the process to stop through OS signal."
kill -15 `cat "$CATALINA_PID"` >/dev/null 2>&1
fi
fi
if [ ! -z "$CATALINA_PID" ]; then
if [ -f "$CATALINA_PID" ]; then
while [ $SLEEP -ge 0 ]; do
kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
if [ $? -gt 0 ]; then
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ -w "$CATALINA_PID" ]; then
cat /dev/null > "$CATALINA_PID"
# If Tomcat has stopped don't try and force a stop with an empty PID file
FORCE=0
else
echo "The PID file could not be removed or cleared."
fi
fi
echo "Tomcat stopped."
break
fi
if [ $SLEEP -gt 0 ]; then
sleep 1
fi
if [ $SLEEP -eq 0 ]; then
echo "Tomcat did not stop in time."
if [ $FORCE -eq 0 ]; then
echo "PID file was not removed."
fi
echo "To aid diagnostics a thread dump has been written to standard out."
kill -3 `cat "$CATALINA_PID"`
fi
SLEEP=`expr $SLEEP - 1 `
done
fi
fi
KILL_SLEEP_INTERVAL=5
if [ $FORCE -eq 1 ]; then
if [ -z "$CATALINA_PID" ]; then
echo "Kill failed: \$CATALINA_PID not set"
else
if [ -f "$CATALINA_PID" ]; then
PID=`cat "$CATALINA_PID"`
echo "Killing Tomcat with the PID: $PID"
kill -9 $PID
while [ $KILL_SLEEP_INTERVAL -ge 0 ]; do
kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
if [ $? -gt 0 ]; then
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ -w "$CATALINA_PID" ]; then
cat /dev/null > "$CATALINA_PID"
else
echo "The PID file could not be removed."
fi
fi
echo "The Tomcat process has been killed."
break
fi
if [ $KILL_SLEEP_INTERVAL -gt 0 ]; then
sleep 1
fi
KILL_SLEEP_INTERVAL=`expr $KILL_SLEEP_INTERVAL - 1 `
done
if [ $KILL_SLEEP_INTERVAL -lt 0 ]; then
echo "Tomcat has not been killed completely yet. The process might be waiting on some system call or might be UNINTERRUPTIBLE."
fi
fi
fi
fi
elif [ "$1" = "configtest" ] ; then
eval "\"$_RUNJAVA\"" $LOGGING_MANAGER $JAVA_OPTS \
-Djava.endorsed.dirs="\"$JAVA_ENDORSED_DIRS\"" -classpath "\"$CLASSPATH\"" \
-Dcatalina.base="\"$CATALINA_BASE\"" \
-Dcatalina.home="\"$CATALINA_HOME\"" \
-Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
org.apache.catalina.startup.Bootstrap configtest
result=$?
if [ $result -ne 0 ]; then
echo "Configuration error detected!"
fi
exit $result
elif [ "$1" = "version" ] ; then
"$_RUNJAVA" \
-classpath "$CATALINA_HOME/lib/catalina.jar" \
org.apache.catalina.util.ServerInfo
else
echo "Usage: catalina.sh ( commands ... )"
echo "commands:"
if $os400; then
echo " debug Start Catalina in a debugger (not available on OS400)"
echo " debug -security Debug Catalina with a security manager (not available on OS400)"
else
echo " debug Start Catalina in a debugger"
echo " debug -security Debug Catalina with a security manager"
fi
echo " jpda start Start Catalina under JPDA debugger"
echo " run Start Catalina in the current window"
echo " run -security Start in the current window with security manager"
echo " start Start Catalina in a separate window"
echo " start -security Start in a separate window with security manager"
echo " stop Stop Catalina, waiting up to 5 seconds for the process to end"
echo " stop n Stop Catalina, waiting up to n seconds for the process to end"
echo " stop -force Stop Catalina, wait up to 5 seconds and then use kill -KILL if still running"
echo " stop n -force Stop Catalina, wait up to n seconds and then use kill -KILL if still running"
echo " configtest Run a basic syntax check on server.xml - check exit code for result"
echo " version What version of tomcat are you running?"
echo "Note: Waiting for the process to end and use of the -force option require that \$CATALINA_PID is defined"
exit 1
fi
找到
if [ -z "$CATALINA_OUT" ] ; then
CATALINA_OUT="$CATALINA_BASE"/logs/catalina.out
将
CATALINA_OUT="$CATALINA_BASE"/logs/catalina.out修改为输出到黑洞CATALINA_OUT=/dev/null这样就再重启tomcat的时候catalina.out就不会出现了