Maven 03-pom.xml core Configuration

The Maven Pom. xml configuration file is not just a configuration dependency package. It can configure more attributes, including plug-in items.

Define environment attributes

• Define some basic variable information in the Pom. xml file
• You can declare the project name, version number, and other related attributes as variables.
• The reference of these variables can be used throughout the configuration to change the content.

<! -- Define environment properties --> <Properties> <project. build. sourceencoding> UTF-8 </project. build. sourceencoding> <JDK. version> 1.8 </JDK. version> <JUnit. version> 4.12 </JUnit. version> <spring. version> 5.1.1.release </spring. version> <servlet. version> 4.0.1 </servlet. version> </Properties> <! -- Reference variable --> <dependencies> <dependency> <groupid> JUnit </groupid> <artifactid> JUnit </artifactid> <version >$ {JUnit. version }</version> </dependency> </dependencies>

Plug-in configuration

• All Maven configurations in myeclipse have no practical significance. They are only valid for the current work zone and projects currently in use.
• To make the entire project effective for a long time, you can set some related plug-ins in the Pom. xml file.

1. Modify the Pom. xml file for JDK compilation plug-in configuration

<Properties> <project. Build. sourceencoding> UTF-8 </Project. Build. sourceencoding> <JDK. version> 1.8 </JDK. version> <! -- Define a public attribute describing the JDK version --> </Properties> <build> <finalname> m2work </finalname> <plugins> <! -- Define the plug-in to be used. There are many plug-ins in Maven --> <plugin> <groupid> org. Apache. Maven. plugins </groupid> <! -- Define the plug-in group information --> <artifactid> Maven-compiler-plugin </artifactid> <! -- Compile the plug-in --> <configuration> <source >$ {JDK. version} </source> <target >$ {JDK. version} </Target> <encode >$ {project. build. sourceencoding} </encode> </configuration> </plugin> </plugins> </build>

2. Overall project update: Alt + F5

• Although myeclipse has already configured a plug-in for the project, this plug-in has no actual effect at this time.
• If you want the configuration to take effect, you also need to update the overall project.

3. You can directly package the program.

4. Output source code jar package

• Modify the Pom. xml configuration file and then package the program directly.

<plugin>    <groupId>org.apache.maven.plugins</groupId>    <artifactId>maven-source-plugin</artifactId>    <configuration>        <encode>${project.build.sourceEncoding}</encode>    </configuration>    <executions>        <execution>            <id>sources</id>            <goals>                <goal>jar</goal>            </goals>        </execution>    </executions></plugin>

5. generate relevant program documents, provided that the Code has detailed comments

• Modify the Pom. xml configuration file and then package the program directly.

<plugin>    <groupId>org.apache.maven.plugins</groupId>    <artifactId>maven-javadoc-plugin</artifactId>    <configuration>        <encode>${project.build.sourceEncoding}</encode>    </configuration>    <executions>        <execution>            <id>javadocs</id>            <goals>                <goal>jar</goal>            </goals>        </execution>    </executions></plugin>

Package Scope

• WEB Project Development packs all development programs into a *. War file.
• In this war file, all third-party development kits will exist.
• For some important development packages, save them in the lib directory.
• If you do not need an SDK, you do not want it to be output to Lib.
• For example, JUnit is only used for testing, but does not want to be output to the war file when the actual project is released.

<dependencies>    <dependency>        <groupId>junit</groupId>        <artifactId>junit</artifactId>        <version>${junit.version}</version>        <scope>test</scope>    </dependency>    <dependency>        <groupId>javax.servlet</groupId>        <artifactId>javax.servlet-api</artifactId>        <version>${servlet.version}</version>        <scope>provided</scope>    </dependency>    <dependency>        <groupId>org.springframework</groupId>        <artifactId>spring-core</artifactId>        <version>${spring.version}</version>    </dependency></dependencies>

• Scope is the scope of the development kit.
• JUnit is only a test environment, so a test scope is used.
• Spring-core does not have any configuration. The default value is compile.
• The servlet package itself is provided by the Tomcat container. Therefore, this package is only valid during project compilation and is not stored in the lib directory.

• Compile
  • Default scope of Dependencies
  • Dependencies are running, testing, and compiling.
• Runtime
  • The dependency is required only during running.
• Test
  • Dependencies are only required during testing.
• Provided
  • Dependencies are only required during compilation and testing. The JDK or runtime container provides
• System
  • The dependency is provided by you and does not need to be downloaded from the maven repository.

Exclusion of dependency packages

• When you control the dependency of a package, you will find other Dependencies with repeated dependencies.
• At this time, only one public commons-logging development package exists in the entire project.

<dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-core</artifactId>    <version>${spring.version}</version>    <exclusions>        <exclusion>            <groupId>commons-logging</groupId>            <artifactId>commons-logging</artifactId>        </exclusion>    </exclusions></dependency>

Inheritance relationship

• In a project, basic configurations such as attributes and related plug-ins are required for almost every Pom. xml file.
• At this time, all the core configuration options are defined in the parent project, and then each sub-project needs to reference the definition in this parent project.

<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> CN. liang </groupid> <artifactid> base </artifactid> <version> 0.0.1-Snapshot </version> <packaging> pom </packaging> <! -- Define a parent Pom. xml file --> <Name> base </Name> <URL> http://maven.apache.org </URL> <! -- In future development, all version controls will be handed over to the base for completion --> <Properties> <project. build. sourceencoding> UTF-8 </project. build. sourceencoding> <JDK. version> 1.8 </JDK. version> <! -- Define a public attribute describing the JDK version --> <JUnit. version> 4.12 </JUnit. version> <spring. version> 5.1.1.release </spring. version> <servlet. version> 4.0.1 </servlet. version> </Properties> <build> <finalname> base </finalname> <plugins> <plugin> <groupid> Org. apache. maven. plugins </groupid> <artifactid> Maven-compiler-plugin </artifactid> <configuration> <source >$ {JDK. version} </source> <target >$ {JDK. version} </Target> <encode >$ {project. build. sourceencoding} </encode> </configuration> </plugin> <groupid> Org. apache. maven. plugins </groupid> <artifactid> Maven-source-plugin </artifactid> <configuration> <encode >$ {project. build. sourceencoding }</encode> </configuration> <executions> <execution> <ID> sources </ID> <goals> <goal> jar </goal> </goals> </execution> </executions> </plugin> <groupid> Org. apache. maven. plugins </groupid> <artifactid> Maven-javadoc-plugin </artifactid> <configuration> <encode >$ {project. build. sourceencoding }</encode> </configuration> <executions> <execution> <ID> javadocs </ID> <goals> <goal> jar </goal> </goals> </execution> </executions> </plugin> </plugins> </build> </Project>

• Pom. xml configuration file for the subitem
• Relevant Properties and configured plug-ins are automatically inherited from the parent project.

<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>  <parent>      <groupId>cn.liang</groupId>      <artifactId>base</artifactId>      <version>0.0.1-SNAPSHOT</version>      <relativePath>../base/pom.xml</relativePath>  </parent>  <artifactId>m2work</artifactId>  <packaging>jar</packaging>  <version>0.0.1</version>   <name>m2work</name>   <url>http://maven.apache.org</url>   <dependencies>      <dependency>          <groupId>junit</groupId>          <artifactId>junit</artifactId>          <version>${junit.version}</version>      </dependency>               <dependency>          <groupId>javax.servlet</groupId>          <artifactId>javax.servlet-api</artifactId>          <version>${servlet.version}</version>      </dependency>                <dependency>          <groupId>org.springframework</groupId>          <artifactId>spring-core</artifactId>          <version>${spring.version}</version>      </dependency>    </dependencies>    <build>      <finalName>m2work</finalName>  </build></project>

• Import the required development kit in the Pom. xml file of the parent class.

<dependencyManagement>  <dependencies>      <dependency>          <groupId>junit</groupId>          <artifactId>junit</artifactId>          <version>${junit.version}</version>      </dependency>  </dependencies> </dependencyManagement>

• However, for sub-projects, you also need to import the SDK, but you do not need to manage version numbers.

<dependencies>      <dependency>          <groupId>junit</groupId>          <artifactId>junit</artifactId>      </dependency>  </dependencies>

Maven 03-pom.xml core Configuration