java - java.library.path中的Ktor No netty_transport_native_epoll_x86_64

Question

在启动Ktor应用程序期间，我得到了以下日志:

java.lang.UnsatisfiedLinkError: no netty_transport_native_epoll_x86_64 in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1871)
    at java.lang.Runtime.loadLibrary0(Runtime.java:872)
    at java.lang.System.loadLibrary(System.java:1124)
    at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at io.netty.util.internal.NativeLibraryLoader$1.run(NativeLibraryLoader.java:369)
    at java.security.AccessController.doPrivileged(Native Method)
    at io.netty.util.internal.NativeLibraryLoader.loadLibraryByHelper(NativeLibraryLoader.java:361)
    at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:339)
    at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:136)
    at io.netty.channel.epoll.Native.loadNativeLibrary(Native.java:231)
    at io.netty.channel.epoll.Native.<clinit>(Native.java:58)
    at io.netty.channel.epoll.Epoll.<clinit>(Epoll.java:39)
    at io.ktor.server.netty.EventLoopGroupProxy$Companion.create(NettyApplicationEngine.kt:189)
    at io.ktor.server.netty.NettyApplicationEngine.<init>(NettyApplicationEngine.kt:74)
    at io.ktor.server.netty.EngineMain.main(EngineMain.kt:22)
22:56:07.760 [main] DEBUG io.netty.util.internal.NativeLibraryLoader - netty_transport_native_epoll_x86_64 cannot be loaded from java.library.path, now trying export to -Dio.netty.native.workdir: /tmp
java.lang.UnsatisfiedLinkError: no netty_transport_native_epoll_x86_64 in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1871)
    at java.lang.Runtime.loadLibrary0(Runtime.java:872)
    at java.lang.System.loadLibrary(System.java:1124)
    at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:38)
    at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:349)
    at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:136)
    at io.netty.channel.epoll.Native.loadNativeLibrary(Native.java:231)
    at io.netty.channel.epoll.Native.<clinit>(Native.java:58)
    at io.netty.channel.epoll.Epoll.<clinit>(Epoll.java:39)
    at io.ktor.server.netty.EventLoopGroupProxy$Companion.create(NettyApplicationEngine.kt:189)
    at io.ktor.server.netty.NettyApplicationEngine.<init>(NettyApplicationEngine.kt:74)
    at io.ktor.server.netty.EngineMain.main(EngineMain.kt:22)
    Suppressed: java.lang.UnsatisfiedLinkError: no netty_transport_native_epoll_x86_64 in java.library.path
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1871)
        at java.lang.Runtime.loadLibrary0(Runtime.java:872)
        at java.lang.System.loadLibrary(System.java:1124)
        at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:38)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at io.netty.util.internal.NativeLibraryLoader$1.run(NativeLibraryLoader.java:369)
        at java.security.AccessController.doPrivileged(Native Method)
        at io.netty.util.internal.NativeLibraryLoader.loadLibraryByHelper(NativeLibraryLoader.java:361)
        at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:339)
        ... 7 common frames omitted
22:56:07.761 [main] DEBUG io.netty.util.internal.NativeLibraryLoader - Unable to load the library 'netty_transport_native_epoll', trying other loading mechanism.
java.lang.UnsatisfiedLinkError: no netty_transport_native_epoll in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1871)
    at java.lang.Runtime.loadLibrary0(Runtime.java:872)
    at java.lang.System.loadLibrary(System.java:1124)
    at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at io.netty.util.internal.NativeLibraryLoader$1.run(NativeLibraryLoader.java:369)
    at java.security.AccessController.doPrivileged(Native Method)
    at io.netty.util.internal.NativeLibraryLoader.loadLibraryByHelper(NativeLibraryLoader.java:361)
    at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:339)
    at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:136)
    at io.netty.channel.epoll.Native.loadNativeLibrary(Native.java:234)
    at io.netty.channel.epoll.Native.<clinit>(Native.java:58)
    at io.netty.channel.epoll.Epoll.<clinit>(Epoll.java:39)
    at io.ktor.server.netty.EventLoopGroupProxy$Companion.create(NettyApplicationEngine.kt:189)
    at io.ktor.server.netty.NettyApplicationEngine.<init>(NettyApplicationEngine.kt:74)
    at io.ktor.server.netty.EngineMain.main(EngineMain.kt:22)
22:56:07.761 [main] DEBUG io.netty.util.internal.NativeLibraryLoader - netty_transport_native_epoll cannot be loaded from java.library.path, now trying export to -Dio.netty.native.workdir: /tmp
java.lang.UnsatisfiedLinkError: no netty_transport_native_epoll in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1871)
    at java.lang.Runtime.loadLibrary0(Runtime.java:872)
    at java.lang.System.loadLibrary(System.java:1124)
    at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:38)
    at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:349)
    at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:136)
    at io.netty.channel.epoll.Native.loadNativeLibrary(Native.java:234)
    at io.netty.channel.epoll.Native.<clinit>(Native.java:58)
    at io.netty.channel.epoll.Epoll.<clinit>(Epoll.java:39)
    at io.ktor.server.netty.EventLoopGroupProxy$Companion.create(NettyApplicationEngine.kt:189)
    at io.ktor.server.netty.NettyApplicationEngine.<init>(NettyApplicationEngine.kt:74)
    at io.ktor.server.netty.EngineMain.main(EngineMain.kt:22)
    Suppressed: java.lang.UnsatisfiedLinkError: no netty_transport_native_epoll in java.library.path
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1871)
        at java.lang.Runtime.loadLibrary0(Runtime.java:872)
        at java.lang.System.loadLibrary(System.java:1124)
        at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:38)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at io.netty.util.internal.NativeLibraryLoader$1.run(NativeLibraryLoader.java:369)
        at java.security.AccessController.doPrivileged(Native Method)
        at io.netty.util.internal.NativeLibraryLoader.loadLibraryByHelper(NativeLibraryLoader.java:361)
        at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:339)
        ... 7 common frames omitted

构建文件

plugins {
    application
    kotlin("jvm") version "1.3.61"
}

group = "io.oceanstack"
version = "1.0-SNAPSHOT"

val ktor_version = "1.3.1"

repositories {
    mavenCentral()
    jcenter()
}

dependencies {
    implementation(kotlin("stdlib-jdk8"))
    compile("io.ktor:ktor-server-core:$ktor_version")
    compile("io.ktor:ktor-server-netty:$ktor_version")
    compile("ch.qos.logback:logback-classic:1.2.3")
    testCompile(group = "junit", name = "junit", version = "4.12")
}

tasks {
    compileKotlin {
        kotlinOptions.jvmTarget = "1.8"
    }
    compileTestKotlin {
        kotlinOptions.jvmTarget = "1.8"
    }
}

application {
    mainClassName = "io.ktor.server.netty.EngineMain"
} 

我究竟做错了什么？

Java运行时:

 java -version
openjdk version "1.8.0_242"
OpenJDK Runtime Environment (Zulu 8.44.0.11-CA-linux64) (build 1.8.0_242-b20)
OpenJDK 64-Bit Server VM (Zulu 8.44.0.11-CA-linux64) (build 25.242-b20, mixed mode)

Answer 1

从debug级别切换到info或warn将隐藏此信息。
如果在更远的日志中

DEBUG io.netty.util.internal.NativeLibraryLoader - Successfully loaded the library /tmp/libnetty_transport_native_epoll_x86_646903432541420558.so

您很安全，应该忽略此消息(进一步)

DEBUG io.netty.util.internal.NativeLibraryLoader - netty_transport_native_epoll_x86_64 cannot be loaded from java.library.path

在找到有效选项之前，它似乎是一种尝试和错误的方法，并且被标记为DEBUG消息，因此对于可能转到INFO或WARNING日志级别或尝试禁止显示此特定消息的库用户而言，相关性较低。
另请参见 here和 here