我正在JMeter中创建自定义Java采样器。它工作得很好。但是，当我希望它以 JSON 格式返回结果时，JMeter 没有找到创建 JSON 所需的 jackson-databind 库的.jar。
我把它放在 JMeter 主目录中的/lib/ext 文件夹中。我也复制到/lib，但无济于事。(我知道/lib/ext 不应该用于依赖关系 jar，但根据我的经验，JMeter 在/lib 中找不到我的实用程序 jar。
我尝试将路径添加到jmeter.properties中的变量search_paths，user.classpath和plugin_dependency_paths。我尝试使用绝对路径、相对路径、斜杠、反斜杠，但都没有帮助。
我尝试将JMETER_HOME变量设置为我的安装地址。它奏效了，但没有帮助。
我尝试在两个环境中运行。第一个是在 Eclipse 中(我将 JMeter 复制到工作区文件夹，然后导入项目)，使用 JMeter 4.0。我在日志中收到此错误：
java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
at (creating ObjectMapper here)
at (creating ResponseJSON here)
at org.apache.jmeter.protocol.java.sampler.JavaSampler.sample(JavaSampler.java:197) ~[ApacheJMeter_java.jar:4.0 r1823414]
at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:490) ~[ApacheJMeter_core.jar:4.0 r1823414]
at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:416) ~[ApacheJMeter_core.jar:4.0 r1823414]
at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:250) ~[ApacheJMeter_core.jar:4.0 r1823414]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_101]
我还从.bat文件中运行了JMeter 3.3，将jars添加到同一位置。我在控制台上收到此错误：
Unknown error checking for existence of class: com.fasterxml.jackson.databind.ObjectMapper
java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/Versioned
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.apache.logging.log4j.util.LoaderUtil.loadClass(LoaderUtil.java:141)
at org.apache.logging.log4j.util.LoaderUtil.isClassAvailable(LoaderUtil.java:115)
at org.apache.logging.log4j.core.util.Loader.isClassAvailable(Loader.java:310)
at org.apache.logging.log4j.core.config.yaml.YamlConfigurationFactory.<init>(YamlConfigurationFactory.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.apache.logging.log4j.core.util.ReflectionUtil.instantiate(ReflectionUtil.java:188)
at org.apache.logging.log4j.core.config.ConfigurationFactory.addFactory(ConfigurationFactory.java:190)
at org.apache.logging.log4j.core.config.ConfigurationFactory.getInstance(ConfigurationFactory.java:164)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:613)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634)
at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
at org.apache.logging.log4j.spi.AbstractLoggerAdapter.getContext(AbstractLoggerAdapter.java:122)
at org.apache.logging.slf4j.Log4jLoggerFactory.getContext(Log4jLoggerFactory.java:43)
at org.apache.logging.log4j.spi.AbstractLoggerAdapter.getLogger(AbstractLoggerAdapter.java:46)
at org.apache.logging.slf4j.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:29)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:358)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:383)
at org.apache.jmeter.JMeter.<clinit>(JMeter.java:109)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.apache.jmeter.NewDriver.main(NewDriver.java:246)
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.core.Versioned
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 43 more
我没有尝试调试类加载器，但当我在这里发布完它时，这可能是下一步。
我有这个版本的文件，与我的POM中相同：
https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind/2.9.4
jackson-databind 依赖项的一部分是您可能缺少的 jackson-core jar，并在错误中包含缺少的类：com.fasterxml.jackson.core.Versioned
参见杰克逊安装：
Jackson JSON API 中的三个 JAR 文件(项目)是：
- 杰克逊核心
- 杰克逊注释
- 杰克逊数据绑定