This article is about how to add library dependency for Maven, using log4j and commons-logging as example.
- Create basic project with maven:
mvn archetype:generate \ -DarchetypeArtifactId=maven-archetype-quickstart \ -DinteractiveMode=false \ -DgroupId=tw.com.codedata \ -DartifactId=helloworld [INFO] Scanning for projects... [INFO] [INFO] ------------------------------------------------------------------------ [INFO] Building Maven Stub Project (No POM) 1 [INFO] ------------------------------------------------------------------------ [INFO] [INFO] >>> maven-archetype-plugin:2.2:generate (default-cli) @ standalone-pom >>> [INFO] [INFO] <<< maven-archetype-plugin:2.2:generate (default-cli) @ standalone-pom <<< [INFO] [INFO] --- maven-archetype-plugin:2.2:generate (default-cli) @ standalone-pom --- [INFO] Generating project in Batch mode [INFO] ---------------------------------------------------------------------------- [INFO] Using following parameters for creating project from Old (1.x) Archetype: maven-archetype-quickstart:1.0 [INFO] ---------------------------------------------------------------------------- [INFO] Parameter: groupId, Value: tw.com.codedata [INFO] Parameter: packageName, Value: tw.com.codedata [INFO] Parameter: package, Value: tw.com.codedata [INFO] Parameter: artifactId, Value: helloworld [INFO] Parameter: basedir, Value: /home/linst/ws/study/maven [INFO] Parameter: version, Value: 1.0-SNAPSHOT [INFO] project created from Old (1.x) Archetype in dir: /home/linst/ws/study/maven/helloworld [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1:46.068s [INFO] Finished at: Mon Sep 29 18:06:53 CST 2014 [INFO] Final Memory: 10M/239M [INFO] ------------------------------------------------------------------------
$ tree . . └── helloworld ├── pom.xml └── src ├── main │ └── java │ └── tw │ └── com │ └── codedata │ └── App.java └── test └── java └── tw └── com └── codedata └── AppTest.java 12 directories, 3 files4.0.0 tw.com.codedata helloworld jar 1.0-SNAPSHOT helloworld http://maven.apache.org junit junit 3.8.1 test - Create file ./helloworld/src/main/resources/log4j.properties:
$ cd helloworld/src/main/ $ mkdir resources $ vim resources/log4j.properties
# Set root logger level to DEBUG and have appenders A1, A2. log4j.rootLogger=DEBUG, A1, A2 # A1 is set to be a ConsoleAppender log4j.appender.A1=org.apache.log4j.ConsoleAppender log4j.appender.A1.layout=org.apache.log4j.PatternLayout log4j.appender.A1.layout.ConversionPattern=[%d{yyyy/MM/dd HH:mm:ss,SSS}][%p][%C-%L] %m%n # A2 is set to be a DailyRollingFileAppender to path "./log/Log4j.log" log4j.appender.A2=org.apache.log4j.DailyRollingFileAppender log4j.appender.A2.layout=org.apache.log4j.PatternLayout log4j.appender.A2.layout.ConversionPattern=[%d{yyyy/MM/dd HH:mm:ss,SSS}][%p][%C-%L] %m%n log4j.appender.A2.File=./log/Log4j.log - Update ./helloworld/src/main/java/tw/com/codedata/App.java to HelloWorld.java with below content:
package tw.com.codedata; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class HelloWorld { static Log logger = LogFactory.getLog(HelloWorld.class); public static void main(String[] args) { logger.info("Hello World"); } } - Try to build, you will get errors because no required logging libraries:
$ cd helloworld/ $ mvn package [INFO] Scanning for projects... [INFO] [INFO] ------------------------------------------------------------------------ [INFO] Building helloworld 1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] [INFO] --- maven-resources-plugin:2.3:resources (default-resources) @ helloworld --- [WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 1 resource [INFO] [INFO] --- maven-compiler-plugin:2.0.2:compile (default-compile) @ helloworld --- [INFO] Compiling 1 source file to /home/linst/ws/study/maven/helloworld/target/classes [INFO] ------------------------------------------------------------------------ [INFO] BUILD FAILURE [INFO] ------------------------------------------------------------------------ [INFO] Total time: 0.792s [INFO] Finished at: Mon Sep 29 18:27:38 CST 2014 [INFO] Final Memory: 8M/239M [INFO] ------------------------------------------------------------------------ [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.0.2:compile (default-compile) on project helloworld: Compilation failure: Compilation failure: [ERROR] /home/linst/ws/study/maven/helloworld/src/main/java/tw/com/codedata/HelloWorld.java:[3,33] package org.apache.commons.logging does not exist [ERROR] [ERROR] /home/linst/ws/study/maven/helloworld/src/main/java/tw/com/codedata/HelloWorld.java:[4,33] package org.apache.commons.logging does not exist [ERROR] [ERROR] /home/linst/ws/study/maven/helloworld/src/main/java/tw/com/codedata/HelloWorld.java:[8,11] cannot find symbol [ERROR] symbol : class Log [ERROR] location: class tw.com.codedata.HelloWorld [ERROR] [ERROR] /home/linst/ws/study/maven/helloworld/src/main/java/tw/com/codedata/HelloWorld.java:[8,24] cannot find symbol [ERROR] symbol : variable LogFactory [ERROR] location: class tw.com.codedata.HelloWorld [ERROR] -> [Help 1] [ERROR] [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch. [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/MojoFailureException
- Update pom.xml to add two dependency:
...junit junit 3.8.1 test commons-logging commons-logging 1.1.1 - Build again:
$ mvn package [INFO] Scanning for projects... [INFO] [INFO] ------------------------------------------------------------------------ [INFO] Building helloworld 1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ Downloading: http://nexus-ams.tomtomgroup.com:8081/nexus/content/groups/public/log4j/log4j/1.2.16/log4j-1.2.16.pom Downloaded: http://nexus-ams.tomtomgroup.com:8081/nexus/content/groups/public/log4j/log4j/1.2.16/log4j-1.2.16.pom (20 KB at 11.4 KB/sec) Downloading: http://nexus-ams.tomtomgroup.com:8081/nexus/content/groups/public/log4j/log4j/1.2.16/log4j-1.2.16.jar Downloaded: http://nexus-ams.tomtomgroup.com:8081/nexus/content/groups/public/log4j/log4j/1.2.16/log4j-1.2.16.jar (471 KB at 111.6 KB/sec) [INFO] [INFO] --- maven-resources-plugin:2.3:resources (default-resources) @ helloworld --- [WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 1 resource [INFO] [INFO] --- maven-compiler-plugin:2.0.2:compile (default-compile) @ helloworld --- [INFO] Compiling 1 source file to /home/linst/ws/study/maven/helloworld/target/classes [INFO] [INFO] --- maven-resources-plugin:2.3:testResources (default-testResources) @ helloworld --- [WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory /home/linst/ws/study/maven/helloworld/src/test/resources [INFO] [INFO] --- maven-compiler-plugin:2.0.2:testCompile (default-testCompile) @ helloworld --- [INFO] Compiling 1 source file to /home/linst/ws/study/maven/helloworld/target/test-classes [INFO] [INFO] --- maven-surefire-plugin:2.10:test (default-test) @ helloworld --- [INFO] Surefire report directory: /home/linst/ws/study/maven/helloworld/target/surefire-reports ------------------------------------------------------- T E S T S ------------------------------------------------------- Running tw.com.codedata.AppTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.009 sec Results : Tests run: 1, Failures: 0, Errors: 0, Skipped: 0 [INFO] [INFO] --- maven-jar-plugin:2.2:jar (default-jar) @ helloworld --- [INFO] Building jar: /home/linst/ws/study/maven/helloworld/target/helloworld-1.0-SNAPSHOT.jar [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 7.618s [INFO] Finished at: Mon Sep 29 18:33:32 CST 2014 [INFO] Final Memory: 13M/239M [INFO] ------------------------------------------------------------------------
. ├── pom.xml ├── src │ ├── main │ │ ├── java │ │ │ └── tw │ │ │ └── com │ │ │ └── codedata │ │ │ ├── App.java~ │ │ │ └── HelloWorld.java │ │ └── resources │ │ └── log4j.properties │ └── test │ └── java │ └── tw │ └── com │ └── codedata │ └── AppTest.java └── target ├── classes │ ├── log4j.properties │ └── tw │ └── com │ └── codedata │ └── HelloWorld.class ├── helloworld-1.0-SNAPSHOT.jar ├── maven-archiver │ └── pom.properties ├── surefire ├── surefire-reports │ ├── TEST-tw.com.codedata.AppTest.xml │ └── tw.com.codedata.AppTest.txt └── test-classes └── tw └── com └── codedata └── AppTest.class 24 directories, 12 files - Run:
$ mvn exec:java -Dexec.mainClass="tw.com.codedata.HelloWorld" [INFO] Scanning for projects... [INFO] [INFO] ------------------------------------------------------------------------ [INFO] Building helloworld 1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] [INFO] --- exec-maven-plugin:1.3.2:java (default-cli) @ helloworld --- [WARNING] Warning: killAfter is now deprecated. Do you need it ? Please comment on MEXEC-6. [2014/09/29 18:38:01,362][INFO][tw.com.codedata.HelloWorld-11] Hello World [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 0.814s [INFO] Finished at: Mon Sep 29 18:38:01 CST 2014 [INFO] Final Memory: 8M/239M [INFO] ------------------------------------------------------------------------
- Reference:
http://www.codedata.com.tw/java/understanding-gradle-2-maven/ [Chinese]
