Gatling包装Shell脚本执行报ClassNotFound错误排查

问题背景 #

编写Shell脚本批量执行Gatling压测，脚本中调用gatling.sh并通过-erjo参数传递JVM系统属性，但执行时出现ClassNotFoundException，系统将JVM选项误当作主类处理。直接复制脚本打印的命令到终端执行却能正常运行。

错误信息 #

GATLING_HOME is set to /home/ec2-user/gatling-charts-highcharts-bundle-3.10.3
20:00:35.108 [DEBUG] i.g.c.ZincCompiler$ - [zinc] IncrementalCompile -----------
20:00:35.116 [DEBUG] i.g.c.ZincCompiler$ - IncrementalCompile.incrementalCompile
20:00:35.121 [DEBUG] i.g.c.ZincCompiler$ - previous = Stamps for: 1 products, 1 sources, 2 libraries
20:00:35.122 [DEBUG] i.g.c.ZincCompiler$ - current source = Set(/home/ec2-user/perf-test/simulation/com/contoso/simulation/OnlineTableSimulation.java)
20:00:35.163 [DEBUG] i.g.c.ZincCompiler$ - > initialChanges = InitialChanges(Changes(added = Set(), removed = Set(), changed = Set(), unmodified = ...),Set(),Set(),API Changes: Set())
20:00:35.167 [DEBUG] i.g.c.ZincCompiler$ - No changes
20:00:35.256 [DEBUG] i.g.c.ZincCompiler$ - Compilation successful
Error: Could not find or load main class "-Dconcurrent_users=4000
Caused by: java.lang.ClassNotFoundException: "-Dconcurrent_users=4000

原因分析 #

脚本中给-erjo、-s、-rf、-rd等参数添加了多余的转义双引号（比如-erjo \"\"-Dconcurrent_users=${users}...\"\"），导致这些引号被作为参数的一部分传递给gatling.sh。当gatling.sh通过"$@"将参数转发给Java命令时，这些多余的引号会被解析成参数内容，Java错误地将"-Dconcurrent_users=4000当作主类名，从而抛出异常。

而直接在终端执行打印的命令时，Shell会自动处理这些引号，将其作为参数边界而非内容，所以能正常运行。

解决方案 #

移除所有参数值周围的转义双引号，直接传递参数即可。Shell会自动处理包含空格的参数，无需额外添加转义引号。

修正后的脚本片段 #

修改do_run函数中的命令打印和执行部分：

echo JAVA_HOME=/usr/lib/jvm/java-11-amazon-corretto.x86_64 \
${HOME}/gatling-charts-highcharts-bundle-3.10.3/bin/gatling.sh \
-rm local \
-s "OnlineTableSimulation" \
-sf "/home/ec2-user/perf-test/simulation" \
-rf "${HOME}/results/${instance}/${users}" \
-erjo "-Dconcurrent_users=${users} -Dendpoint=${endpoint} -Dtoken=${token}" \
-rd "${instance} instance, ${users} concurrent users"

export JAVA_HOME=/usr/lib/jvm/java-11-amazon-corretto.x86_64

echo
echo "Running simulation:"
echo

${HOME}/gatling-charts-highcharts-bundle-3.10.3/bin/gatling.sh \
-erjo "-Dconcurrent_users=${users} -Dendpoint=${endpoint} -Dtoken=${token}" \
-rm local \
-s "OnlineTableSimulation" \
-sf "/home/ec2-user/perf-test/simulation" \
-rf "${HOME}/results/${instance}/${users}" \
-rd "${instance} instance, ${users} concurrent users"

关键修正点 #

• 去掉-erjo、-s、-rf、-rd参数值外层的\"\"，只保留一层双引号包裹带空格或变量的参数
• 确保变量（如${users}、${endpoint}）在双引号内正确展开，同时Shell能识别参数边界

内容的提问来源于stack exchange，提问作者feroze