如何使 Netty 示例工作
How to make the Netty example works
我正在尝试下载 Netty Source Code 和 运行 包含的示例。
我安装的jdk版本是1.8.0_65。
我尝试使用 maven(mvn eclipse:eclipse) 将示例（在示例文件夹 ...\netty-4.1\example 中）转换为 eclipse 项目。
但是遇到下面所说的构建错误。
[INFO]
[INFO] >>> maven-eclipse-plugin:2.10:eclipse (default-cli) > generate-resources @ netty-example >>>
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.558 s
[INFO] Finished at: 2016-02-04T13:40:13+08:00
[INFO] Final Memory: 11M/28M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project netty-example: Could not resolve dependencies for project io.netty:netty-example:jar:4.1.0.CR2-SNAPSHOT: Failure to fi
nd io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be r
eattempted until the update interval of central has elapsed or updates are forced -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal on project netty-example: Could not resolve dependencies for project io.netty:net
ty-example:jar:4.1.0.CR2-SNAPSHOT: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached i
n the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.getDependencies(LifecycleDependencyResolver.java:221)
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.resolveProjectDependencies(LifecycleDependencyResolver.java:127)
at org.apache.maven.lifecycle.internal.MojoExecutor.ensureDependenciesAreResolved(MojoExecutor.java:245)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:199)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.MojoExecutor.executeForkedExecutions(MojoExecutor.java:352)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:197)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
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:497)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.project.DependencyResolutionException: Could not resolve dependencies for project io.netty:netty-example:jar:4.1.0.CR2-SNAPSHOT: Fai
lure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution wil
l not be reattempted until the update interval of central has elapsed or updates are forced
at org.apache.maven.project.DefaultProjectDependenciesResolver.resolve(DefaultProjectDependenciesResolver.java:211)
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.getDependencies(LifecycleDependencyResolver.java:195)
... 27 more
Caused by: org.eclipse.aether.resolution.DependencyResolutionException: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo
.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are
forced
at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:384)
at org.apache.maven.project.DefaultProjectDependenciesResolver.resolve(DefaultProjectDependenciesResolver.java:205)
... 28 more
Caused by: org.eclipse.aether.resolution.ArtifactResolutionException: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.m
aven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are fo
rced
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:444)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifacts(DefaultArtifactResolver.java:246)
at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:367)
... 29 more
Caused by: org.eclipse.aether.transfer.ArtifactNotFoundException: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven
.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced
at org.eclipse.aether.internal.impl.DefaultUpdateCheckManager.newException(DefaultUpdateCheckManager.java:231)
at org.eclipse.aether.internal.impl.DefaultUpdateCheckManager.checkArtifact(DefaultUpdateCheckManager.java:206)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.gatherDownloads(DefaultArtifactResolver.java:585)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.performDownloads(DefaultArtifactResolver.java:503)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:421)
... 31 more
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
然后我按照消息中提到的线索进行了追踪。我找到 this solution which link to the http://netty.io/wiki/forked-tomcat-native.html#wiki-h3-6.
我认为这可能不适合我的目的。（我只想 运行 示例）。
所以我想知道要下载什么Netty开发库来开始Netty应用程序开发。或者任何 Pom.xml 共享 link 可以很容易地包含在示例项目中？谢谢。
看日志，好像找不到tcnative jar
Failure to find
io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in
https://repo.maven.apache.org/maven2 was cached in the local
repository,
你能尝试使用 maven 从命令行下载这个 tcnative jar 吗？
mvn org.apache.maven.plugins:maven-dependency-plugin:get -DrepoUrl=http://central.maven.org/maven2/ -DgroupId=io.netty -DartifactId=netty-tcnative -Dversion=1.1.33.Fork11
根据Netty项目上的bug report回答
要构建Netty 项目，您应该使用64 位操作系统并结合64 位JVM。这是因为 Netty 项目使用的依赖项中有 1 个仅支持 64 位。
根据 mvn -version 的输出，您 运行 正在 32 位 JVM 上运行。您应该能够从 official java website.
下载 64 位 JVM
升级到 64 位 JVM 还具有以下优点：
- 您可以 运行 内存超过 2 GB 的程序
- 使用
long 和 double 的计算会更快，因为 java 可以使用本机处理器
差异见：Benefits of 64bit java platform
示例不需要自己编译，也可以在maven central上找到，按版本排序：http://central.maven.org/maven2/io/netty/netty-example/
我正在尝试下载 Netty Source Code 和 运行 包含的示例。
我安装的jdk版本是1.8.0_65。
我尝试使用 maven(mvn eclipse:eclipse) 将示例（在示例文件夹 ...\netty-4.1\example 中）转换为 eclipse 项目。
但是遇到下面所说的构建错误。
[INFO]
[INFO] >>> maven-eclipse-plugin:2.10:eclipse (default-cli) > generate-resources @ netty-example >>>
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.558 s
[INFO] Finished at: 2016-02-04T13:40:13+08:00
[INFO] Final Memory: 11M/28M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project netty-example: Could not resolve dependencies for project io.netty:netty-example:jar:4.1.0.CR2-SNAPSHOT: Failure to fi
nd io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be r
eattempted until the update interval of central has elapsed or updates are forced -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal on project netty-example: Could not resolve dependencies for project io.netty:net
ty-example:jar:4.1.0.CR2-SNAPSHOT: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached i
n the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.getDependencies(LifecycleDependencyResolver.java:221)
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.resolveProjectDependencies(LifecycleDependencyResolver.java:127)
at org.apache.maven.lifecycle.internal.MojoExecutor.ensureDependenciesAreResolved(MojoExecutor.java:245)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:199)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.MojoExecutor.executeForkedExecutions(MojoExecutor.java:352)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:197)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
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:497)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.project.DependencyResolutionException: Could not resolve dependencies for project io.netty:netty-example:jar:4.1.0.CR2-SNAPSHOT: Fai
lure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution wil
l not be reattempted until the update interval of central has elapsed or updates are forced
at org.apache.maven.project.DefaultProjectDependenciesResolver.resolve(DefaultProjectDependenciesResolver.java:211)
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.getDependencies(LifecycleDependencyResolver.java:195)
... 27 more
Caused by: org.eclipse.aether.resolution.DependencyResolutionException: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo
.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are
forced
at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:384)
at org.apache.maven.project.DefaultProjectDependenciesResolver.resolve(DefaultProjectDependenciesResolver.java:205)
... 28 more
Caused by: org.eclipse.aether.resolution.ArtifactResolutionException: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.m
aven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are fo
rced
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:444)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifacts(DefaultArtifactResolver.java:246)
at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:367)
... 29 more
Caused by: org.eclipse.aether.transfer.ArtifactNotFoundException: Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven
.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced
at org.eclipse.aether.internal.impl.DefaultUpdateCheckManager.newException(DefaultUpdateCheckManager.java:231)
at org.eclipse.aether.internal.impl.DefaultUpdateCheckManager.checkArtifact(DefaultUpdateCheckManager.java:206)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.gatherDownloads(DefaultArtifactResolver.java:585)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.performDownloads(DefaultArtifactResolver.java:503)
at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:421)
... 31 more
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
然后我按照消息中提到的线索进行了追踪。我找到 this solution which link to the http://netty.io/wiki/forked-tomcat-native.html#wiki-h3-6.
我认为这可能不适合我的目的。（我只想 运行 示例）。
所以我想知道要下载什么Netty开发库来开始Netty应用程序开发。或者任何 Pom.xml 共享 link 可以很容易地包含在示例项目中？谢谢。
看日志，好像找不到tcnative jar
Failure to find io.netty:netty-tcnative:jar:windows-x86_32:1.1.33.Fork11 in https://repo.maven.apache.org/maven2 was cached in the local repository,
你能尝试使用 maven 从命令行下载这个 tcnative jar 吗？
mvn org.apache.maven.plugins:maven-dependency-plugin:get -DrepoUrl=http://central.maven.org/maven2/ -DgroupId=io.netty -DartifactId=netty-tcnative -Dversion=1.1.33.Fork11
根据Netty项目上的bug report回答
要构建Netty 项目，您应该使用64 位操作系统并结合64 位JVM。这是因为 Netty 项目使用的依赖项中有 1 个仅支持 64 位。
根据 mvn -version 的输出，您 运行 正在 32 位 JVM 上运行。您应该能够从 official java website.
升级到 64 位 JVM 还具有以下优点：
- 您可以 运行 内存超过 2 GB 的程序
- 使用
long和double的计算会更快，因为 java 可以使用本机处理器
差异见：Benefits of 64bit java platform
示例不需要自己编译，也可以在maven central上找到，按版本排序：http://central.maven.org/maven2/io/netty/netty-example/