java echo 服务器_编译和运行 Echo 服务器和客户端 落日映苍穹つ 2022-11-06 04:56 145阅读 0赞 编译和运行 Echo 服务器和客户端 \#\#\#编译 本例涉及到多模块 Maven 项目的组织 在例子 chapter2 目录下，执行 mvn clean package 输出如下 Listing 2.6 Build Output chapter2>mvn clean package \[INFO\] Scanning for projects... \[INFO\] -------------------------------------------------------------------- \[INFO\] Reactor Build Order: \[INFO\] \[INFO\] Echo Client and Server \[INFO\] Echo Client \[INFO\] Echo Server \[INFO\] \[INFO\] -------------------------------------------------------------------- \[INFO\] Building Echo Client and Server 1.0-SNAPSHOT \[INFO\] -------------------------------------------------------------------- \[INFO\] \[INFO\] --- maven-clean-plugin:2.5:clean (default-clean) @ echo-parent --- \[INFO\] \[INFO\] -------------------------------------------------------------------- \[INFO\] Building Echo Client 1.0-SNAPSHOT \[INFO\] -------------------------------------------------------------------- \[INFO\] \[INFO\] --- maven-clean-plugin:2.5:clean (default-clean) @ echo-client --- \[INFO\] \[INFO\] --- maven-compiler-plugin:3.1:compile (default-compile) @ echo-client --- \[INFO\] Changes detected - recompiling the module! \[INFO\] -------------------------------------------------------------------- \[INFO\] Reactor Summary: \[INFO\] \[INFO\] Echo Client and Server ......................... SUCCESS \[ 0.118 s\] \[INFO\] Echo Client .................................... SUCCESS \[ 1.219 s\] \[INFO\] Echo Server .................................... SUCCESS \[ 0.110 s\] \[INFO\] -------------------------------------------------------------------- \[INFO\] BUILD SUCCESS \[INFO\] -------------------------------------------------------------------- \[INFO\] Total time: 1.561 s \[INFO\] Finished at: 2014-06-08T17:39:15-05:00 \[INFO\] Final Memory: 14M/245M \[INFO\] -------------------------------------------------------------------- 注意事项： Maven Reactor 构建顺序：先是 父 POM，然后是子项目 Netty artifact 没在用户的本地存储库中找到，所以 Maven 就会从互联网上下载 clean 和 compile 在构建生命周期的运行。事后 mavensurefire-plugin 插件运行，但不会有测试类存在。最后 mavenjar-plugin 执行 这段说明了项目已经成功编译。 \#\#\#运行 Echo 服务器 和 客户端 我们使用 exec-maven-plugin 来运行项目。 在 chapter2/Server 目录，执行 mvn exec:java 输出如下： \[INFO\] Scanning for projects... \[INFO\] \[INFO\] -------------------------------------------------------------------- \[INFO\] Building Echo Server 1.0-SNAPSHOT \[INFO\] -------------------------------------------------------------------- \[INFO\] \[INFO\] >>> exec-maven-plugin:1.2.1:java (default-cli) @ echo-server >>> \[INFO\] \[INFO\] <<< exec-maven-plugin:1.2.1:java (default-cli) @ echo-server <<< \[INFO\] \[INFO\] --- exec-maven-plugin:1.2.1:java (default-cli) @ echo-server --- nettyinaction.echo.EchoServer started and listening for connections on /0:0:0:0:0:0:0:0:9999 在 chapter2/Client 目录，执行 mvn exec:java 输出如下： \[INFO\] Scanning for projects... \[INFO\] \[INFO\] -------------------------------------------------------------------- \[INFO\] Building Echo Client 1.0-SNAPSHOT \[INFO\] -------------------------------------------------------------------- \[INFO\] \[INFO\] >>> exec-maven-plugin:1.2.1:java (default-cli) @ echo-client >>> \[INFO\] \[INFO\] <<< exec-maven-plugin:1.2.1:java (default-cli) @ echo-client <<< \[INFO\] \[INFO\] --- exec-maven-plugin:1.2.1:java (default-cli) @ echo-client --- Client received: Netty rocks! \[INFO\] -------------------------------------------------------------------- \[INFO\] BUILD SUCCESS \[INFO\] -------------------------------------------------------------------- \[INFO\] Total time: 3.907 s \[INFO\] Finished at: 2014-06-08T18:26:14-05:00 \[INFO\] Final Memory: 8M/245M \[INFO\] -------------------------------------------------------------------- 在服务器的控制台输出： Server received: Netty rocks! 发生了什么事： 客户端连接后，它发送消息：“Netty rocks！” 服务器输出接收到消息并将其返回给客户端 客户输出接收到的消息并退出。 每次运行客户端，你会看到在服务器的控制台输出： Server received: Netty rocks! 现在，我们看下错误的情况。在控制台 输入 Ctrl-C 来关闭服务器。而后运行客户端，此时输出如下： \[INFO\] Scanning for projects... \[INFO\] \[INFO\] -------------------------------------------------------------------- \[INFO\] Building Echo Client 1.0-SNAPSHOT \[INFO\] -------------------------------------------------------------------- \[INFO\] \[INFO\] >>> exec-maven-plugin:1.2.1:java (default-cli) @ echo-client >>> \[INFO\] \[INFO\] <<< exec-maven-plugin:1.2.1:java (default-cli) @ echo-client <<< \[INFO\] \[INFO\] --- exec-maven-plugin:1.2.1:java (default-cli) @ echo-client --- \[WARNING\] java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:297) at java.lang.Thread.run(Thread.java:744) Caused by: java.net.ConnectException: Connection refused: no further information: localhost/127.0.0.1:9999 at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect (SocketChannelImpl.java:739) at io.netty.channel.socket.nio.NioSocketChannel .doFinishConnect(NioSocketChannel.java:191) at io.netty.channel.nio. AbstractNioChannel$AbstractNioUnsafe.finishConnect( AbstractNioChannel.java:279) at io.netty.channel.nio.NioEventLoop .processSelectedKey(NioEventLoop.java:511) at io.netty.channel.nio.NioEventLoop .processSelectedKeysOptimized(NioEventLoop.java:461) at io.netty.channel.nio.NioEventLoop .processSelectedKeys(NioEventLoop.java:378) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:350) at io.netty.util.concurrent .SingleThreadEventExecutor$2.run (SingleThreadEventExecutor.java:101) ... 1 more \[INFO\] -------------------------------------------------------------------- \[INFO\] BUILD FAILURE \[INFO\] -------------------------------------------------------------------- \[INFO\] Total time: 3.728 s \[INFO\] Finished at: 2014-06-08T18:49:13-05:00 \[INFO\] Final Memory: 8M/245M \[INFO\] -------------------------------------------------------------------- \[ERROR\] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project echo-client: An exception occured while executing the Java class. null: InvocationTargetException: Connection refused: no further information: localhost/127.0.0.1:9999 -> \[Help 1\] 发生了啥？客户端尝试连接服务器，但服务器是关闭的，所以引发了一个 java.net.ConnectException ，这个异常被 EchoClientHandler 的 exceptionCaught() 触发，打印出异常信息，并关闭 channel
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