在許多Java工程中,經(jīng)常會(huì)看到帶有程序自定義參數(shù)調(diào)用Java命令的包裝shell腳本。例如,
$ANT_HOME/bin/ant, $GROOVY_HOME/bin/groovy
,甚至在我們的TimeMachine Scheduler程序中也能見(jiàn)到
$TIMEMACHINE_HOME/bin/scheduler.sh
編寫(xiě)這些包裝腳本很無(wú)聊而且容易出錯(cuò)。大多數(shù)的問(wèn)題來(lái)自為程序設(shè)置正確的classpath。如果你正在為一個(gè)公司開(kāi)發(fā)內(nèi)部項(xiàng)目的話,那么你有可能遠(yuǎn)離糾結(jié)的路徑以及環(huán)境變量問(wèn)題。但是對(duì)于開(kāi)源項(xiàng)目,人們需要使包裝更加靈活和通用。大多數(shù)甚至提供了.bat版本。Windows DOS確實(shí)是個(gè)野蠻且被限制的終端而不能很好的滿足你項(xiàng)目腳本需求。因此,我常鼓勵(lì)別人盡量還是多使用Cygwi。至少它具備一個(gè)真實(shí)的bash shell。其他常見(jiàn)的問(wèn)題就是這些包裝很快就會(huì)失去控制而且在你的項(xiàng)目各處都會(huì)出現(xiàn)很多冗余腳本。
run-java包裝腳本介紹
如果你看到 $TIMEMACHINE_HOME/bin/scheduler.sh 的代碼,你會(huì)看到它其實(shí)是在同目錄下循環(huán)調(diào)用run-java腳本。
DIR=$(dirname $0)SCHEDULER_HOME=$DIR/..$DIR/run-java -Dscheduler.home="$SCHEDULER_HOME" timemachine.scheduler.tool.SchedulerServer "$@"
正如你看到的,我們的 run-java 可以使用 -D 選項(xiàng),不僅這樣,它同樣也能使用 -cp 選項(xiàng)!而且,你還能在main class后面指定這些選項(xiàng)!這樣能夠使得run-java被其他的腳本包裝,并且仍舊能夠添加額外的系統(tǒng)屬性以及classpath。
例如,TimeMachine 附帶了 Groovy 庫(kù),所以你可以簡(jiǎn)單的像這樣調(diào)用
groovy:$TIMEMACHINE_HOME/bin/run-java groovy.ui.GroovyMain test.groovy
你可以很方便地在任何目錄下使用,它確認(rèn)自己的目錄然后可以自動(dòng)加載lib目錄下的任何jar包。現(xiàn)在如果你想要附加更多的jar包來(lái)運(yùn)行Groovy的話,可以如下使用 -cp 選項(xiàng):
$TIMEMACHINE_HOME/bin/run-java -cp "$HOME/apps/my-app/lib/*" groovy.ui.GroovyMain test.groovy
RUN_JAVA_DRY=1 $TIMEMACHINE_HOME/bin/run-java -cp "$HOME/apps/my-app/lib/*" groovy.ui.GroovyMain test.groovy
你只需在命令提示行中運(yùn)行上面一整行代碼即可。它將輸出完整的附帶所有選項(xiàng)和參數(shù)的java命令。
run-script還包含很多其它的選項(xiàng),你可以通過(guò)查看其注釋了解。當(dāng)前的腳本能夠在任何的Linux bash和Windows Cygwin中運(yùn)行。
在開(kāi)發(fā)中通過(guò)Maven使用 run-java
根據(jù)上面提到的示例,假設(shè)項(xiàng)目發(fā)布結(jié)構(gòu)如下:
$TIMEMACHINE_HOME +- bin/run-java +- lib/*.jar
但是在開(kāi)發(fā)過(guò)程中目錄會(huì)是怎樣呢?一個(gè)常見(jiàn)的用例便是:你希望能夠運(yùn)行target/classes下最新編譯的代碼而不是將整個(gè)項(xiàng)目打包或者發(fā)布。你同樣可以在此種情況下使用 run-java 。首先,簡(jiǎn)單的將 bin/run-java 添加進(jìn)你的項(xiàng)目,然后運(yùn)行
mvn compile dependency:copy-dependencies
將會(huì)在target/dependency下生成所有的jar文件。就只需要做這些。run-java將自動(dòng)的檢測(cè)這些目錄,并為你的main class創(chuàng)建正確的classpath。
如果你使用Eclipse來(lái)開(kāi)發(fā),那么你的target/classes目錄將總是在更新的,run-java便能成為你項(xiàng)目開(kāi)發(fā)中的瑰寶。
獲取 run-java 包裝腳本
#!/usr/bin/env bash## Copyright 2012 Zemian Deng## Licensed 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. # A wrapper script that run any Java6 application in unix/cygwin env.## This script is assumed to be located in an application's "bin" directory. It will# auto resolve any symbolic link and always run in relative to this application# directory (which is one parent up from the script.) Therefore, this script can be# run any where in the file system and it will still reference this application# directory.## This script will by default auto setup a Java classpath that picks up any "config"# and "lib" directories under the application directory. It also will also add a# any typical Maven project output directories such as "target/test-classes",# "target/classes", and "target/dependency" into classpath. This can be disable by# setting RUN_JAVA_NO_PARSE=1.## If the "Default parameters" section bellow doesn't match to user's env, then user# may override these variables in their terminal session or preset them in shell's# profile startup script. The values of all path should be in cygwin/unix path,# and this script will auto convert them into Windows path where is needed.## User may customize the Java classpath by setting RUN_JAVA_CP, which will prefix to existing# classpath, or use the "-cp" option, which will postfix to existing classpath.## Usage:# run-java [java_opts] <java_main_class> [-cp /more/classpath] [-Dsysprop=value]## Example:# run-java example.Hello# run-java example.Hello -Dname=World# run-java org.junit.runner.JUnitCore example.HelloTest -cp "C:/apps/lib/junit4.8.2/*"## Created by: Zemian Deng 03/09/2012 # This run script dir (resolve to absolute path)SCRIPT_DIR=$(cd $(dirname $0) && pwd) # This dir is where this script live.APP_DIR=$(cd $SCRIPT_DIR/.. && pwd) # Assume the application dir is one level up from script dir. # Default parametersJAVA_HOME=${JAVA_HOME:=/apps/jdk} # This is the home directory of Java development kit.RUN_JAVA_CP=${RUN_JAVA_CP:=$CLASSPATH} # A classpath prefix before -classpath option, default to $CLASSPATHRUN_JAVA_OPTS=${RUN_JAVA_OPTS:=} # Java options (-Xmx512m -XX:MaxPermSize=128m etc)RUN_JAVA_DEBUG=${RUN_JAVA_DEBUG:=} # If not empty, print the full java command line before executing it.RUN_JAVA_NO_PARSE=${RUN_JAVA_NO_PARSE:=} # If not empty, skip the auto parsing of -D and -cp options from script arguments.RUN_JAVA_NO_AUTOCP=${RUN_JAVA_NO_AUTOCP:=} # If not empty, do not auto setup Java classpathRUN_JAVA_DRY=${RUN_JAVA_DRY:=} # If not empty, do not exec Java command, but just print # OS specific support. $var _must_ be set to either true or false.CYGWIN=false;case "`uname`" in CYGWIN*) CYGWIN=true ;;esac # Define where is the java executable isJAVA_CMD=javaif [ -d "$JAVA_HOME" ]; then JAVA_CMD="$JAVA_HOME/bin/java"fi # Auto setup applciation's Java Classpath (only if they exists)if [ -z "$RUN_JAVA_NO_AUTOCP" ]; then if $CYGWIN; then # Provide Windows directory conversion JAVA_HOME_WIN=$(cygpath -aw "$JAVA_HOME") APP_DIR_WIN=$(cygpath -aw "$APP_DIR") if [ -d "$APP_DIR_WIN/config" ]; then RUN_JAVA_CP="$RUN_JAVA_CP;$APP_DIR_WIN/config" ; fi if [ -d "$APP_DIR_WIN/target/test-classes" ]; then RUN_JAVA_CP="$RUN_JAVA_CP;$APP_DIR_WIN/target/test-classes" ; fi if [ -d "$APP_DIR_WIN/target/classes" ]; then RUN_JAVA_CP="$RUN_JAVA_CP;$APP_DIR_WIN/target/classes" ; fi if [ -d "$APP_DIR_WIN/target/dependency" ]; then RUN_JAVA_CP="$RUN_JAVA_CP;$APP_DIR_WIN/target/dependency/*" ; fi if [ -d "$APP_DIR_WIN/lib" ]; then RUN_JAVA_CP="$RUN_JAVA_CP;$APP_DIR_WIN/lib/*" ; fi else if [ -d "$APP_DIR/config" ]; then RUN_JAVA_CP="$RUN_JAVA_CP:$APP_DIR/config" ; fi if [ -d "$APP_DIR/target/test-classes" ]; then RUN_JAVA_CP="$RUN_JAVA_CP:$APP_DIR/target/test-classes" ; fi if [ -d "$APP_DIR/target/classes" ]; then RUN_JAVA_CP="$RUN_JAVA_CP:$APP_DIR/target/classes" ; fi if [ -d "$APP_DIR/target/dependency" ]; then RUN_JAVA_CP="$RUN_JAVA_CP:$APP_DIR/target/dependency/*" ; fi if [ -d "$APP_DIR/lib" ]; then RUN_JAVA_CP="$RUN_JAVA_CP:$APP_DIR/lib/*" ; fi fifi # Parse addition "-cp" and "-D" after the Java main class from script arguments# This is done for convenient sake so users do not have to export RUN_JAVA_CP and RUN_JAVA_OPTS# saparately, but now they can pass into end of this run-java script instead.# This can be disable by setting RUN_JAVA_NO_PARSE=1.if [ -z "$RUN_JAVA_NO_PARSE" ]; then # Prepare variables for parsing FOUND_CP= declare -a NEW_ARGS IDX=0 # Parse all arguments and look for "-cp" and "-D" for ARG in "$@"; do if [[ -n $FOUND_CP ]]; then if [ "$OS" = "Windows_NT" ]; then # Can't use cygpath here, because cygpath will auto expand "*", which we do not # want. User will just have to use OS path when specifying "-cp" option. #ARG=$(cygpath -w -a $ARG) RUN_JAVA_CP="$RUN_JAVA_CP;$ARG" else RUN_JAVA_CP="$RUN_JAVA_CP:$ARG" fi FOUND_CP= else case $ARG in '-cp') FOUND_CP=1 ;; '-D'*) RUN_JAVA_OPTS="$RUN_JAVA_OPTS $ARG" ;; *) NEW_ARGS[$IDX]="$ARG" let IDX=$IDX+1 ;; esac fi done # Display full Java command. if [ -n "$RUN_JAVA_DEBUG" ] || [ -n "$RUN_JAVA_DRY" ]; then echo "$JAVA_CMD" $RUN_JAVA_OPTS -cp "$RUN_JAVA_CP" "${NEW_ARGS[@]}" fi # Run Java Main class using parsed variables if [ -z "$RUN_JAVA_DRY" ]; then "$JAVA_CMD" $RUN_JAVA_OPTS -cp "$RUN_JAVA_CP" "${NEW_ARGS[@]}" fielse # Display full Java command. if [ -n "$RUN_JAVA_DEBUG" ] || [ -n "$RUN_JAVA_DRY" ]; then echo "$JAVA_CMD" $RUN_JAVA_OPTS -cp "$RUN_JAVA_CP" "$@" fi # Run Java Main class if [ -z "$RUN_JAVA_DRY" ]; then "$JAVA_CMD" $RUN_JAVA_OPTS -cp "$RUN_JAVA_CP" "$@" fifi
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