chengevo
commented
9 years ago The problem is about modules in a maven project. By following this stackoverflow threadI have it worked out.
Create maven project
Firstly create a directory, say netty-example, where source files in each chapter will reside.
mkdir netty-example
cd netty-examplethen
mvn archetype:generate \
-DarchetypeGroupId=org.codehaus.mojo.archetypes \
-DarchetypeArtifactId=pom-root \
-DarchetypeVersion=RELEASEwhile prompt asks for groupId and artifactId, give such input:
this creates a maven project for chapter 2, the structure of directory netty-example would looks like this:
- netty-example
- chapter02
- pom.xmlThen, go into directory chapter02, and creates two maven module for server and client side respectively:
mvn archetype:generate \
-DarchetypeGroupId=org.apache.maven.archetypes \
-DarchetypeArtifactId=maven-archetype-quickstart \
-DarchetypeVersion=RELEASEWhile asks for groupId and artifactId, for both server and client modules, the groupId would be com.example, and the artifactId would be server and client respectively.
Copy EchoClient.java and EchoClientHandler into client/src/main/java/com/example/, then copy EchoServer.java and EchoServerHandler into server/src/main/java/com/example. Right now, the structure of directory netty-example should looks like this(remember to delete App.class pre generated in both directory):
Configure maven project
Change pom.xml inside directory chapter02 with following content:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.chengevo</groupId>
<artifactId>netty-demon</artifactId>
<version>1.0-SNAPSHOT</version>
<modules>
<module>server</module>
<module>client</module>
</modules>
<packaging>pom</packaging>
<name>netty-demon</name>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<configuration>
<optimize>true</optimize>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>${netty.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>2.5.0</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty.npn</groupId>
<artifactId>npn-api</artifactId>
<version>${npn.version}</version>
</dependency>
<dependency>
<groupId>org.mortbay.jetty.npn</groupId>
<artifactId>npn-boot</artifactId>
<version>${npn.boot.version}</version>
<scope>runtime</scope>
</dependency>
</dependencies>
<properties>
<npn.version>1.1.0.v20120525</npn.version>
<npn.boot.version>1.1.10.v20150130</npn.boot.version>
<netty.version>4.0.25.Final</netty.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>
</project>Change the pom.xml inside client directory into this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>chapter02</artifactId>
<groupId>com.example</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>client</artifactId>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
<execution>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
<configuration>
<mainClass>com.example.EchoClient</mainClass>
<arguments>
<argument>0.0.0.0</argument>
<argument>9999</argument>
</arguments>
</configuration>
</plugin>
</plugins>
</build>
</project>Change the pom.xml inside server directory into this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>chapter02</artifactId>
<groupId>com.example</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>server</artifactId>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
<execution>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
<configuration>
<mainClass>com.example.EchoServer</mainClass>
<arguments>
<argument>9999</argument>
</arguments>
</configuration>
</plugin>
</plugins>
</build>
</project>Note:
mainClasstag specifies which class will be executed while the program runsargumenttag nested inargumentstag specifies the first, the second etc command line argument passed to the program. Thus in the example above, the first command line argument is0.0.0.0, and the second command line argument is9999, ie the port that client and server listens to.
Run the client and server
the go back to directory chapter02, run the command
mvn clean packageinside client and server directory, fires up both client and server side:
mvn exec:java
mwolfthal
jamestweeddale
As per the book, there should be a separate Maven sub module for each chapter. But it is a flat structure in the Github. Due to this inconsistency, the instructions for running some of the examples (e.g. ch.2) are invalid.