mvn clean package: no main manifest attribute [dup

2019-08-23 20:12发布

问题:

This question already has an answer here:

  • Can't execute jar- file: “no main manifest attribute” 34 answers

While the project executes from the IDE, how is the JAR created so that a hello world type console app will actually run?

thufir@dur:~/NetBeansProjects/HelloMaven$ 
thufir@dur:~/NetBeansProjects/HelloMaven$ mvn clean package
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] Building HelloMaven 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ HelloMaven ---
[INFO] Deleting /home/thufir/NetBeansProjects/HelloMaven/target
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ HelloMaven ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ HelloMaven ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /home/thufir/NetBeansProjects/HelloMaven/target/classes
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ HelloMaven ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/thufir/NetBeansProjects/HelloMaven/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ HelloMaven ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ HelloMaven ---
[INFO] No tests to run.
[INFO] 
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ HelloMaven ---
[INFO] Building jar: /home/thufir/NetBeansProjects/HelloMaven/target/HelloMaven-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.400 s
[INFO] Finished at: 2017-10-21T10:50:42-07:00
[INFO] Final Memory: 14M/47M
[INFO] ------------------------------------------------------------------------
thufir@dur:~/NetBeansProjects/HelloMaven$ 
thufir@dur:~/NetBeansProjects/HelloMaven$ tree
.
├── nbactions.xml
├── pom.xml
├── src
│   ├── main
│   │   ├── java
│   │   │   └── net
│   │   │       └── bounceme
│   │   │           └── dur
│   │   │               └── hello_maven
│   │   │                   └── Main.java
│   │   └── resources
│   └── test
│       └── java
└── target
    ├── classes
    │   └── net
    │       └── bounceme
    │           └── dur
    │               └── hello_maven
    │                   └── Main.class
    ├── generated-sources
    │   └── annotations
    ├── HelloMaven-1.0-SNAPSHOT.jar
    ├── maven-archiver
    │   └── pom.properties
    └── maven-status
        └── maven-compiler-plugin
            ├── compile
            │   └── default-compile
            │       ├── createdFiles.lst
            │       └── inputFiles.lst
            └── testCompile
                └── default-testCompile
                    └── inputFiles.lst

25 directories, 9 files
thufir@dur:~/NetBeansProjects/HelloMaven$ 
thufir@dur:~/NetBeansProjects/HelloMaven$ java -jar target/HelloMaven-1.0-SNAPSHOT.jar 
no main manifest attribute, in target/HelloMaven-1.0-SNAPSHOT.jar
thufir@dur:~/NetBeansProjects/HelloMaven$ 

apparently just need to specify the Main-Class entry for the manifest.

Just focusing on the package phase:

Running Maven Tools Maven Phases

Although hardly a comprehensive list, these are the most common default lifecycle phases executed.

validate: validate the project is correct and all necessary information is available compile: compile the source code of the project test: test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed package: take the compiled code and package it in its distributable format, such as a JAR. integration-test: process and deploy the package if necessary into an environment where integration tests can be run verify: run any checks to verify the package is valid and meets quality criteria install: install the package into the local repository, for use as a dependency in other projects locally deploy: done in an integration or release environment, copies the final package to the remote repository for sharing with other developers and projects

回答1:

I see, it's a matter of using the shade plugin:

thufir@dur:~/NetBeansProjects/HelloMaven$ 
thufir@dur:~/NetBeansProjects/HelloMaven$ mvn clean package
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] Building HelloMaven 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ HelloMaven ---
[INFO] Deleting /home/thufir/NetBeansProjects/HelloMaven/target
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ HelloMaven ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ HelloMaven ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /home/thufir/NetBeansProjects/HelloMaven/target/classes
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ HelloMaven ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/thufir/NetBeansProjects/HelloMaven/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ HelloMaven ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ HelloMaven ---
[INFO] No tests to run.
[INFO] 
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ HelloMaven ---
[INFO] Building jar: /home/thufir/NetBeansProjects/HelloMaven/target/HelloMaven-1.0-SNAPSHOT.jar
[INFO] 
[INFO] --- maven-shade-plugin:3.1.0:shade (default) @ HelloMaven ---
[INFO] Replacing original artifact with shaded artifact.
[INFO] Replacing /home/thufir/NetBeansProjects/HelloMaven/target/HelloMaven-1.0-SNAPSHOT.jar with /home/thufir/NetBeansProjects/HelloMaven/target/HelloMaven-1.0-SNAPSHOT-shaded.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.805 s
[INFO] Finished at: 2017-10-21T11:02:31-07:00
[INFO] Final Memory: 17M/56M
[INFO] ------------------------------------------------------------------------
thufir@dur:~/NetBeansProjects/HelloMaven$ 
thufir@dur:~/NetBeansProjects/HelloMaven$ java -jar target/HelloMaven-1.0-SNAPSHOT.jar 
Oct 21, 2017 11:02:38 AM net.bounceme.dur.hello_maven.Main getGreeting
INFO: Hello world.
thufir@dur:~/NetBeansProjects/HelloMaven$ 
thufir@dur:~/NetBeansProjects/HelloMaven$ cat pom.xml 
<?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">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany</groupId>
    <artifactId>HelloMaven</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.1.0</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>net.bounceme.dur.hello_maven.Main</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>
thufir@dur:~/NetBeansProjects/HelloMaven$ 

http://maven.apache.org/plugins/maven-shade-plugin/examples/executable-jar.html