maven 高级玩法

标签（空格分隔）： maven

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实用技巧

Maven 提速

多线程

# 用 4 个线程构建，以及根据 CPU 核数每个核分配 1 个线程进行构建

$ mvn -T 4 clean install

$ mvn -T 1C clean install

跳过测试

-DskipTests               # 不执行测试用例，但编译测试用例类生成相应的 class 文件至 target/test-classes 下

-Dmaven.test.skip=true    # 不执行测试用例，也不编译测试用例类

# 结合上文的`并行执行`

$ mvn -T 1C clean install -Dmaven.test.skip=true

# 如果还是阻塞: 资源管理器 - shutdown all java app

# 如果 jar 包过大，可以下载按照路径放在 repository 中，之后可能还需要 mvn clean 来下载 groovy-all-2.3.11.pom 文件 (mvnrepository.com)

D:\apps\maven\repository\org\codehaus\groovy\groovy-all\2.3.11\groovy-all-2.3.11.jar

编译失败后，接着编译

# 如果是 Apache Eagle 之类带有几十个子项目的工程，如果从头编译所有的模块，会很耗功夫

# 通过指定之前失败的模块名，可以继续之前的编译

$ mvn -rf :moduleName clean install

跳过失败的模块，编译到最后再报错

$ mvn clean install --fail-at-end

使用 Nexus 本地私服

http://www.cnblogs.com/quanyongan/archive/2013/04/24/3037589.html

使用 Aliyun 国内镜像

可以大大提高编译下载速度

<mirror>

  <id>alimaven</id>

  <name>aliyun maven</name>

  <url>http://maven.aliyun.com/nexus/content/groups/public/</url>

  <mirrorOf>central</mirrorOf>

</mirror>

指定 Repository 目录

<!-- Default: ~/.m2/repository  -->

<localRepository>D:\apps\maven\repository</localRepository>

如何使用 Maven 编译指定 module

$ mvn install -pl <module_name> -am

  -pl, --projects      (Build specified reactor projects instead of all project)

  -am, --also-make     (If project list is specified, also build projects required by the list)

  -amd, --also-make-dependents    (If project list is specified, also build projects that depend on)

Maven 标准目录结构

src/main/java             Application/Library sources

src/main/resources        Application/Library resources

src/main/filters          Resource filter files

src/main/webapp           Web application sources

src/test/java             Test sources

src/test/resources        Test resources

src/test/filters          Test resource filter files

src/it                    Integration Tests (primarily for plugins)

src/assembly              Assembly descriptors

src/site                  Site

LICENSE.txt               Project's license

NOTICE.txt                Notices and attributions required by libraries that the project depends on

README.txt                Project's readme

如何在 Maven 中使用多个 source

<plugin>

  <groupId>org.codehaus.mojo</groupId>

  <artifactId>build-helper-maven-plugin</artifactId>

  <executions>

    <execution>

      <phase>generate-sources</phase>

      <goals>

        <goal>add-source</goal>

      </goals>

      <configuration>

        <sources>

          <source>src/main/scala</source>

        </sources>

      </configuration>

    </execution>

  </executions>

</plugin>

Using Scala UnitTest by Maven

安装 Scala

Maven 依赖

<dependency>

  <groupId>org.scalatest</groupId>

  <artifactId>scalatest_2.10</artifactId>

  <version>2.2.1</version>

</dependency>

创建 unittest 需要的 trait

import org.scalatest._

abstract class UnitTestStyle extends FlatSpec

with Matchers with OptionValues with Inside with Inspectors

编写测试

import spark.streaming.detect.SendNetflow

class SendNetflowTest extends UnitTestStyle {

  "Clean method" should "output a string" in {

    val s = "0,tcp,http,SF,229,9385,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,9,9,0.00,0.00,0.00,0.00,1.00,0.00,0.00,9,90,1.00,0.00,0.11,0.04,0.00,0.00,0.00,0.00,normal."

    SendNetflow.clean(s) should be("0,229,9385,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,9,9,0.00,0.00,0.00,0.00,1.00,0.00,0.00,9,90,1.00,0.00,0.11,0.04,0.00,0.00,0.00,0.00\tnormal.")

  }

  it should "throw Exception if an empty string is inputted" in {

    val emptyS = ""

    a[RuntimeException] should be thrownBy {

    SendNetflow.clean(emptyS)

  }

}

Using slf4j by Maven

Maven 配置

<slf4j.version>1.7.12</slf4j.version>

<logback.version>1.1.3</logback.version>

<dependency>

  <groupId>ch.qos.logback</groupId>

  <artifactId>logback-core</artifactId>

  <version>${logback.version}</version>

</dependency>

<dependency>

  <groupId>ch.qos.logback</groupId>

  <artifactId>logback-classic</artifactId>

  <version>${logback.version}</version>

  <exclusions>

    <exclusion>

      <groupId>ch.qos.logback</groupId>

      <artifactId>logback-core</artifactId>

    </exclusion>

    <exclusion>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-api</artifactId>

    </exclusion>

  </exclusions>

</dependency>

<dependency>

  <groupId>org.slf4j</groupId>

  <artifactId>slf4j-api</artifactId>

  <version>${slf4j.version}</version>

</dependency>

<dependency>

  <groupId>org.slf4j</groupId>

  <artifactId>jcl-over-slf4j</artifactId>

  <version>${slf4j.version}</version>

  <exclusions>

    <exclusion>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-api</artifactId>

    </exclusion>

  </exclusions>

</dependency>

<dependency>

  <groupId>org.slf4j</groupId>

  <artifactId>log4j-over-slf4j</artifactId>

  <version>${slf4j.version}</version>

  <exclusions>

    <exclusion>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-api</artifactId>

    </exclusion>

  </exclusions>

</dependency>

<dependency>

  <groupId>org.slf4j</groupId>

  <artifactId>jul-to-slf4j</artifactId>

  <version>${slf4j.version}</version>

  <exclusions>

    <exclusion>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-api</artifactId>

    </exclusion>

  </exclusions>

</dependency>

logback.xml in resources directory

<?xml version="1.0" encoding="UTF-8"?>

<configuration>

  <!-- %p:Level %m:Message %c.%M:Package+Method %F:%L:File+Line -->

  <property name="pattern" value="%d{yyyy-MM-dd HH:mm:ss.SSS} | %p | %m | %c.%M | %F:%L %n"/>

  <!-- Print in Console -->

  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">

    <encoder charset="UTF-8">

    <pattern>${pattern}</pattern>

    </encoder>

  </appender>

  <root level="ALL">

    <appender-ref ref="STDOUT"/>

  </root>

</configuration>

编码

示例

private static final Logger log = LoggerFactory.getLogger(ZKEventWatch.class);

log.info(state);

遇到的坑

SLF4J multi bindings

遇到的坑

SLF4J: Class path contains multiple SLF4J bindings.

SLF4J: Found binding in [jar:file:/D:/apps/maven/repository/ch/qos/logback/logback-classic/1.1.3/logback-classic-1.1.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]

SLF4J: Found binding in [jar:file:/D:/apps/maven/repository/org/slf4j/slf4j-log4j12/1.6.1/slf4j-log4j12-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]

解决

<!-- 使用 Apache Curator 需要 exclusion slf4j-log4j12，否则会出现问题 -->

<dependency>

  <groupId>org.apache.curator</groupId>

  <artifactId>curator-recipes</artifactId>

  <version>${apache.curator.version}</version>

  <exclusions>

    <exclusion>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-log4j12</artifactId>

    </exclusion>

  </exclusions>

</dependency>

导出依赖 Jar

<build>

  <plugins>

    <plugin>

    <groupId>org.apache.maven.plugins</groupId>

    <artifactId>maven-dependency-plugin</artifactId>

    <version>2.10</version>

    <configuration>

      <outputDirectory>${project.build.directory}/lib</outputDirectory>

      <excludeTransitive>false</excludeTransitive>

      <stripVersion>false</stripVersion>

    </configuration>

    </plugin>

  </plugins>

</build>

$ mvn clean dependency:copy-dependencies

# 将 yuzhouwan-flume 依赖的 jars 都 导出到一个文件夹

# 用相对路径，不能是 绝对路径，否则 maven 会报错：Unknown lifecycle phase "Java"

$ mvn dependency:copy-dependencies -f yuzhouwan-flume/pom.xml -DoutputDirectory=yuzhouwan-flume/target/lib

$ mvn dependency:copy-dependencies -f yuzhouwan-api/yuzhouwan-admin-api/pom.xml -DoutputDirectory=target/lib

Profiles

日志级别

-Dorg.slf4j.simpleLogger.defaultLogLevel=error

Generate Code for Antlr

 mvn clean install -T 1C -DskipTests=true -Dorg.slf4j.simpleLogger.defaultLogLevel=error -B

Maven Properties

mvn clean install -Dmy.property=propertyValue

Maven Check Style

 mvn clean install -Dcheckstyle.skip

Maven Update

$ mvn clean install -U

# -U means force update of dependencies.

Maven License Check

参考http://code.mycila.com/license-maven-plugin/

Maven Dependency

Pre-download

$ mvn dependency:go-offline

Version-compare

# 在开发一些 Coprocessor 的时候，需要保证和 HBase 集群的依赖 jar 版本一致，可以使用该方法

$ mvn versions:compare-dependencies -DremotePom=org.apache.hbase:hbase:0.98.8-hadoop2 -DreportOutputFile=depDiffs.txt

Maven Proxy

命令行设置

# Linux (bash)

$ export MAVEN_OPTS="-DsocksProxyHost=10.10.10.10 -DsocksProxyPort=8080"

# Windows

$ set MAVEN_OPTS="-DsocksProxyHost=10.10.10.10 -DsocksProxyPort=8080"

配置文件 maven setting.xml

  <proxies>

    <!--<proxy>

      <id>http-proxy</id>

      <active>true</active>

      <protocol>http</protocol>

      <host>10.10.10.10</host>

      <port>8888</port>

      <nonProxyHosts>*.yuzhouwan.com</nonProxyHosts>

    </proxy>-->

    <proxy>

      <id>socks-proxy</id>

      <active>true</active>

      <protocol>socks5</protocol>

      <host>127.0.0.1</host>

      <port>1080</port>

      <nonProxyHosts>*.yuzhouwan.com</nonProxyHosts>

    </proxy>

  </proxies>

Avro 插件

创建 avsc 文件

{

  "namespace": "com.yuzhouwan.hacker.avro",

  "type": "record",

  "name": "User",

  "fields": [

    {

      "name": "name",

      "type": "string"

    },

    {

      "name": "favorite_number",

      "type": [

        "int",

        "null"

      ]

    },

    {

      "name": "favorite_color",

      "type": [

        "string",

        "null"

      ]

    }

  ]

}

使用 avro-tools 工具生成 Avro 类

# 下载 avro-tools

# https://mvnrepository.com/artifact/org.apache.avro/avro-tools/1.8.1

# http://archive.apache.org/dist/avro/avro-1.8.1/java/                    (better)

$ wget http://archive.apache.org/dist/avro/avro-1.8.1/java/avro-tools-1.8.1.jar -c avro-tools-1.8.1.jar

# 利用 avsc 文件中的 Schema 生成 Avro 类

$ java -jar avro-tools-1.8.1.jar compile schema user.avsc .

使用 avro-plugin 插件生成 Avro 类

<properties>

  <apache.avro.version>1.7.7</apache.avro.version>

</properties>

<dependencies>

  <!-- apache avro -->

  <dependency>

    <groupId>org.apache.avro</groupId>

    <artifactId>avro</artifactId>

    <version>${apache.avro.version}</version>

  </dependency>

</dependencies>

<build>

  <plugins>

    <plugin>

      <groupId>org.apache.avro</groupId>

      <artifactId>avro-maven-plugin</artifactId>

      <version>${apache.avro.version}</version>

      <executions>

        <execution>

          <phase>generate-sources</phase>

          <goals>

            <goal>schema</goal>

          </goals>

          <configuration>

            <sourceDirectory>${project.basedir}/src/main/resources/avsc/</sourceDirectory>

            <outputDirectory>${project.basedir}/src/main/java/</outputDirectory>

          </configuration>

        </execution>

      </executions>

    </plugin>

  </plugins>

</build>

Shade 插件解决 Jar 多版本共存

适用场景

在整合大型项目时，可能都依赖 commons-collections 此类的工具包，但是也可能 commons-collections 的版本却因为不一致，导致冲突。可以通过 Shade 插件的 relocation 方法进行重定向，此时冲突的依赖 package 名，会被重命名，并且依赖该 jar 的程序，都会被自动替换为新的 package 名

基本用法

实例一

<properties>

    <maven.shade.plugin.version>2.4.3</maven.shade.plugin.version>

</properties>

<plugin>

    <groupId>org.apache.maven.plugins</groupId>

    <artifactId>maven-shade-plugin</artifactId>

    <version>2.4.3</version>

    <executions>

        <execution>

            <phase>package</phase>

            <goals>

                <goal>shade</goal>

            </goals>

            <configuration>

                <shadedArtifactAttached>false</shadedArtifactAttached>

                <createSourcesJar>true</createSourcesJar>

                <artifactSet>

                    <excludes>

                        <exclude>org.mapdb.*</exclude>

                    </excludes>

                </artifactSet>

                <relocations>

                    <relocation>

                        <pattern>org.apache.commons.collections</pattern>

                        <shadedPattern>com.yuzhouwan.org.apache.commons.collections</shadedPattern>

                    </relocation>

                </relocations>

            </configuration>

        </execution>

    </executions>

</plugin>

实例二

<plugin>

    <groupId>org.apache.maven.plugins</groupId>

    <artifactId>maven-shade-plugin</artifactId>

    <version>${maven.shade.plugin.version}</version>

    <executions>

        <execution>

            <phase>package</phase>

            <goals>

                <goal>shade</goal>

            </goals>

            <configuration>

                <shadedArtifactAttached>true</shadedArtifactAttached>

                <shadedClassifierName>all</shadedClassifierName>

                <createSourcesJar>true</createSourcesJar>

                <artifactSet>

                    <!-- 因为 org.glassfish 里面存在类似 public static class Builder implements javax.ws.rs.client.Invocation.Builder 全限定名的写法 -->

                    <!-- 所以只能用 shade 去隐藏 com.sun.jersey -->

                    <excludes>

                        <exclude>org.glassfish.*</exclude>

                    </excludes>

                </artifactSet>

                <relocations>

                    <relocation>

                        <pattern>javax.ws</pattern>

                        <shadedPattern>shade.javax.ws</shadedPattern>

                    </relocation>

                    <relocation>

                        <pattern>org.apache.curator</pattern>

                        <shadedPattern>shade.org.apache.curator</shadedPattern>

                    </relocation>

                    <!--<relocation>

                        <pattern>org.glassfish</pattern>

                        <shadedPattern>shade.org.glassfish</shadedPattern>

                    </relocation>

                    <relocation>

                        <pattern>com.sun.jersey</pattern>

                        <shadedPattern>shade.com.sun.jersey</shadedPattern>

                    </relocation>-->

                </relocations>

            </configuration>

        </execution>

    </executions>

</plugin>

通过 Shade 将问题解决后，部署上线后，依赖冲突复现

　因为官方明确指出 java.io.File.listFiles() 方法返回的文件序列顺序，是不做保证的。所以，上线后运行环境发生变化，加载 lib 目录下的 jar 包顺序，可能会发生变化。这时候，就需要利用不同 lib 目录，并修改 classpath 的方式，将 jar 包加载顺序确定下来

　例如，在整合 Druid 这类依赖树比较庞大的工程，就遇到了这么一种情况。Druid 中 com.sun.jersey (1.19) 和 Dataflow 中 org.glassfish.jersey (2.25.1) 发生冲突。增加了上述实例二中的 Shade 操作仍然会在线上环境，复现依赖冲突。这时，我们可以通过增加一个 lib_jersey 目录，存放 javax.ws.rs-api-2.1.jar，并修改 classpath 为 lib_jersey/*:lib/*。以此，保证了 lib_jersey 中的依赖得以优先加载，从而解决冲突

参考

http://maven.apache.org/plugins/maven-shade-plugin/

Assembly 插件

不同模块的依赖，打包到不同的目录下

具体步骤

第一步，先在负责打包分发的 distribution 模块中，设置 pom.xml 文件

<properties>

    <maven.assembly.plugin.version>2.3</maven.assembly.plugin.version>

</properties>

<packaging>pom</packaging>

<dependencies>

    <dependency>

        <groupId>com.yuzhouwan</groupId>

        <artifactId>core</artifactId>

    </dependency>

    <dependency>

        <groupId>com.yuzhouwan</groupId>

        <artifactId>ai</artifactId>

    </dependency>

    <dependency>

        <groupId>com.yuzhouwan</groupId>

        <artifactId>bigdata</artifactId>

    </dependency>

</dependencies>

<build>

    <plugins>

        <plugin>

            <artifactId>maven-assembly-plugin</artifactId>

            <version>${maven.assembly.plugin.version}</version>

            <executions>

                <execution>

                    <id>assemble</id>

                    <phase>package</phase>

                    <goals>

                        <goal>single</goal>

                    </goals>

                    <configuration>

                        <descriptors>

                            <descriptor>src/assembly/bin.xml</descriptor>

                            <descriptor>src/assembly/src.xml</descriptor>

                        </descriptors>

                        <tarLongFileMode>gnu</tarLongFileMode>

                    </configuration>

                </execution>

            </executions>

        </plugin>

    </plugins>

</build>

第二步，创建好对应的 bin.xml 和 src.xml

<assembly xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

          xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"

          xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">

    <id>bin</id>

    <formats>

        <format>dir</format>

        <format>tar.gz</format>

    </formats>

    <baseDirectory>yuzhouwan-${project.version}-bin</baseDirectory>

    <fileSets>

        <fileSet>

            <directory>../</directory>

            <excludes>

                <exclude>**/target/**</exclude>

                <exclude>**/.classpath</exclude>

                <exclude>**/.project</exclude>

                <exclude>**/.settings/**</exclude>

                <exclude>lib/**</exclude>

                <exclude>conf/**</exclude>

            </excludes>

            <includes>

                <include>README</include>

                <include>LICENSE</include>

                <include>NOTICE</include>

                <include>CHANGELOG</include>

                <include>RELEASE-NOTES</include>

                <include>conf/</include>

            </includes>

        </fileSet>

        <fileSet>

            <directory>../</directory>

            <includes>

                <include>bin/yuzhouwan-cli.sh</include>

            </includes>

            <fileMode>0777</fileMode>

            <directoryMode>0755</directoryMode>

        </fileSet>

    </fileSets>

    <moduleSets>

        <moduleSet>

            <includeSubModules>false</includeSubModules>

            <useAllReactorProjects>true</useAllReactorProjects>

            <includes>

                <include>com.yuzhouwan:yuzhouwan-core</include>

            </includes>

            <excludes>

                <exclude>com.yuzhouwan:ai</exclude>

                <exclude>com.yuzhouwan:bigdata</exclude>

            </excludes>

            <binaries>

                <outputDirectory>lib/core</outputDirectory>

                <unpack>false</unpack>

                <dependencySets>

                    <dependencySet>

                        <useProjectArtifact>false</useProjectArtifact>

                        <useTransitiveDependencies>true</useTransitiveDependencies>

                        <unpack>false</unpack>

                        <excludes>

                            <exclude>com.yuzhouwan:ai</exclude>

                            <exclude>com.yuzhouwan:bigdata</exclude>

                        </excludes>

                    </dependencySet>

                </dependencySets>

            </binaries>

        </moduleSet>

        <moduleSet>

            <includeSubModules>false</includeSubModules>

            <useAllReactorProjects>true</useAllReactorProjects>

            <includes>

                <include>com.yuzhouwan:ai</include>

            </includes>

            <excludes>

                <exclude>com.yuzhouwan:bigdata</exclude>

            </excludes>

            <binaries>

                <outputDirectory>lib/plugins/ai</outputDirectory>

                <unpack>false</unpack>

                <dependencySets>

                    <dependencySet>

                        <useProjectArtifact>false</useProjectArtifact>

                        <useTransitiveDependencies>true</useTransitiveDependencies>

                        <unpack>false</unpack>

                        <excludes>

                            <exclude>com.yuzhouwan:bigdata</exclude>

                        </excludes>

                    </dependencySet>

                </dependencySets>

            </binaries>

        </moduleSet>

        <moduleSet>

            <includeSubModules>false</includeSubModules>

            <useAllReactorProjects>true</useAllReactorProjects>

            <includes>

                <include>com.yuzhouwan:bigdata</include>

            </includes>

            <excludes>

                <exclude>com.yuzhouwan:ai</exclude>

            </excludes>

            <binaries>

                <outputDirectory>lib/plugins/bigdata</outputDirectory>

                <unpack>false</unpack>

                <dependencySets>

                    <dependencySet>

                        <useProjectArtifact>false</useProjectArtifact>

                        <useTransitiveDependencies>true</useTransitiveDependencies>

                        <unpack>false</unpack>

                        <excludes>

                            <exclude>com.yuzhouwan:ai</exclude>

                        </excludes>

                    </dependencySet>

                </dependencySets>

            </binaries>

        </moduleSet>

    </moduleSets>

</assembly>

<assembly xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

          xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"

          xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">

    <id>src</id>

    <formats>

        <format>dir</format>

        <format>tar.gz</format>

    </formats>

    <baseDirectory>yuzhouwan-${project.version}-src</baseDirectory>

    <fileSets>

        <fileSet>

            <directory>../</directory>

            <excludes>

                <exclude>**/target/**</exclude>

                <exclude>**/.classpath</exclude>

                <exclude>**/.project</exclude>

                <exclude>**/*.iml</exclude>

                <exclude>**/.settings/**</exclude>

                <exclude>lib/**</exclude>

            </excludes>

            <includes>

                <include>.ci</include>

                <include>.gitignore</include>

                <include>DEVNOTES</include>

                <include>README</include>

                <include>LICENSE</include>

                <include>NOTICE</include>

                <include>CHANGELOG</include>

                <include>RELEASE-NOTES</include>

                <include>bin/**</include>

                <include>conf/**</include>

                <include>native/**</include>

                <include>pom.xml</include>

                <include>dev-conf/**</include>

                <include>yuzhouwan-core/**</include>

                <include>yuzhouwan-ai/**</include>

                <include>yuzhouwan-bigdata/**</include>

            </includes>

        </fileSet>

    </fileSets>

</assembly>

构建完成之后，即可看到 yuzhouwan-ai 和 yuzhouwan-bigdata 模块的依赖，分别被打包到了 plugins/ai 和 plugins/bigdata 目录下

# 需要预先安装 tree 命令（yum install tree -y）

$ tree

  .

  ├── bin

  │   └── yuzhouwan-cli.sh

  └── lib

      ├── core

      └── plugins

          ├── ai

          └── bigdata

踩过的坑

模块间存在版本冲突的 jar 包

问题描述

Currently, inclusion of module dependencies may produce unpredictable results if a version conflict occurs

解决：

如果上述 yuzhouwan-ai 和 yuzhouwan-bigdata 模块，与 yuzhouwan-common 模块存在版本冲突的 jar 包，则需要将 bin.xml 拆解成 bin-common.xml、bin-ai.xml 和 bin-bigdata.xml 三个 assembly 配置文件，依次进行构建（此时需要将 id 设置成一样的，不然会被构建到不同的目录下）。否则，版本冲突的 jar 包，将只能保留其中一个版本，且具体保留哪个版本是不确定的

常见问题

Maven Archetype 的选择

Maven web 项目

选择 Archetype 的时候，选择 maven-archetype-webapp

其他语言编译出来的 Jar

Clojar

如果需要在 Maven 中，添加不是 Maven 中央仓库的 Repository，例如 Clojar：

<repositories>

  <repository>

    <id>clojars.org</id>

    <url>http://clojars.org/repo</url>

  </repository>

</repositories>

本地缓存

Maven 中出现 Repository 被缓存在本地，则可以添加下面属性

<repository>

  <id>clojars.org</id>

  <url>http://clojars.org/repo</url>

  <releases>

    <enabled>true</enabled>

    <updatePolicy>always</updatePolicy>

  </releases>

  <snapshots>

    <enabled>true</enabled>

    <updatePolicy>always</updatePolicy>

  </snapshots>

</repository>

编译问题

JDK 版本不一致

描述：

Error:java: Compilation failed: internal java compiler error

解决：

<build>

  <finalName>elastic-netflow-v5</finalName>

  <plugins>

    <plugin>

      <groupId>org.apache.maven.plugins</groupId>

      <artifactId>maven-compiler-plugin</artifactId>

      <version>2.3.2</version>

      <configuration>

        <source>1.7</source>

        <target>1.7</target>

      </configuration>

    </plugin>

    <plugin>

      <groupId>org.apache.maven.plugins</groupId>

      <artifactId>maven-release-plugin</artifactId>

      <version>2.4.1</version>

    </plugin>

  </plugins>

</build>

Scala 版本不一致

描述：

[ERROR] error: error while loading <root>, Error accessing D:\.m2\repository\org\apache\curator\curator-client\2.4.0\curator-client-2.4.0.jar

[ERROR] error: scala.reflect.internal.MissingRequirementError: object java.lang.Object in compiler mirror not found.

解决：

查看 pom 文件中指定的 scala 版本，切换到对应的版本，进行编译即可

存在没有下载好的依赖

描述：

Error creating properties files for forking; nested exception is java.io.IOException: No such file or directory

解决：

mvn dependency::tree

离线build

$ mvn install -o

本地 mvn clean install 到 .m2/repository 中的 jar 和 仓库中的不一致时

描述:

"Class not found 'xxxx' Empty test suite" in java unittest, after change the modules' names

解决：

Maven ->Reimport->Generte Source and Update Folder

Ctrl + F9->Make Project

打包存在脏程序:

war:war 之前需要先执行 mvn clean install。否则，会因为 profiles 的缘故，导致 war 包中 缺少文件

语法问题

Maven 中无法识别 ${project.version}

需要将所有（除了 root / parent 模块）的 <version>1.0</version> 中的具体版本号（如 1.0.0）全部替换成 "${project.version}"

插件问题

xxx module must not contain source root. the root already belongs to module xxx

解决:

Artifacts Setting  ->  Modules -> Sourc tab

delete the fold by clicking on the X icon to the right of it

ExecutionException The forked VM terminated without properly saying goodbye

描述：

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test (default-test) on project eagle-app-streamproxy: ExecutionException The forked VM terminated without properly saying goodbye. VM crash or System.exit called?

解决

<plugin>

  <groupId>org.apache.maven.plugins</groupId>

  <artifactId>maven-surefire-plugin</artifactId>

  <version>${maven-surefire.version}</version>

  <configuration>

    <!-- 增加 argLine 参数以调整 JVM -->

    <argLine>-Xmx2048m -Xms1024m -XX:MaxPermSize=512m -XX:-UseGCOverheadLimit</argLine>

    <forkMode>always</forkMode>

  </configuration>

</plugin>

Assembly 插件报错 java.lang.StackOverflowError

解决：

# 调大默认的堆栈大小

export MAVEN_OPTS=-Xss2m

补充：

-Xms：jvm 进程启动时分配的内存

-Xmx：jvm 进程运行过程中最大能分配到的内存

-Xss：jvm 进程中启动线程，为每个线程分配的内存大小

依赖问题

Maven 中央仓库找不到对应版本的依赖

如何将其他项目的 jar 安装到 maven 仓库中

1,利用命令安装

$ mvn install:install-file -Dfile=<jar 包的位置> -DgroupId=<上面的 groupId> -DartifactId=<上面的 artifactId> -Dversion=<上面的 version> -Dpackaging=jar -DgeneratePom=true -DpomFile=<指定一个 pom.xml 添加进去>

$ mvn install:install-file -Dfile=G:\ES\yuzhouwan_netflow-rest\lib\ite-esmanage-0.7.2-SNAPSHOT.jar -DgroupId=ite -DartifactId=esmanage -Dversion=0.7.2-SNAPSHOT -Dpackaging=jar -DgeneratePom=true -DpomFile=C:\yuzhouwan\Maven\pom.xml

# -DgeneratePom 没有成功

# 原因是 这个第三方的 jar 中，pom.xml 路径不对，必须手动 copy 出来，并用 -DpomFile 的方式导入

2,利用插件安装

<!-- 注意：${project.basedir} 是当前模块的根目录，需要把依赖包，放对位置 -->

<build>

    <pluginManagement>

        <plugins>

            <plugin>

                <groupId>org.apache.maven.plugins</groupId>

                <artifactId>maven-install-plugin</artifactId>

                <version>2.5.2</version>

                <executions>

                    <execution>

                        <id>install-external</id>

                        <phase>clean</phase>

                        <configuration>

                            <file>${project.basedir}/lib/flume-hdfs-sink-${flume.version}.jar</file>

                            <repositoryLayout>default</repositoryLayout>

                            <groupId>org.apache.flume.flume-ng-sinks</groupId>

                            <artifactId>flume-hdfs-sink</artifactId>

                            <version>${flume.version}</version>

                            <packaging>jar</packaging>

                            <generatePom>true</generatePom>

                        </configuration>

                        <goals>

                            <goal>install-file</goal>

                        </goals>

                    </execution>

                </executions>

            </plugin>

        </plugins>

    </pluginManagement>

</build>

控制 Scope 范围

# compile（编译范围）

　compile 范围是默认的。编译范围依赖在所有的 classpath 中可用，同时它们也会被打包

# provided（已提供范围）

　provided 范围只有在当 JDK 或者一个容器已提供该依赖之后才使用。它们不是传递性的，也不会被打包。适用于在实现了公共 common 模块，其中有很多依赖，但是只有在其他依赖了 common 模块的子模块中，重新声明依赖，才会真正被打包到子模块中。这样，既可以保证 common 模块的正常编译，又可以减少子模块中的依赖包大小

# runtime（运行时范围）

　runtime 范围在运行和测试系统的时候需要，但在编译的时候不需要。例如，在编译的时候，如果只需要 JDBC API Jar，但只有在运行的时候才需要 JDBC 驱动的具体实现

# test（测试范围）

　test 范围在一般的编译和运行时都不需要，它们只有在测试编译和测试运行阶段可用。常用于 JUnit 的依赖

# system（系统范围）

　system 范围与 provided 类似，但是必须显式的提供一个对于本地系统中 Jar 文件的路径。这么做是为了允许基于本地对象编译（systemPath），而这些对象是系统类库的一部分。这样的构件应该是一直可用的，Maven 也不会在仓库中去寻找它（不推荐使用）

引入某一个本身依赖树很庞大的 Dependency

# 依赖列表

$ mvn dependency:list

# 依赖树（这里推荐直接用 Intellij Idea 中自带的 "Show Dependencies" 功能，可视化地展示依赖树 和 对应依赖冲突，并能够直接对 依赖树进行修剪）

$ mvn dependency:tree

# 依赖分析

$ mvn dependency:analyze

  Unused declared dependencies  表示项目中未使用的，但显示声明的依赖

  Used undeclared dependencies  表示项目中使用到的，但是没有显示声明的依赖

Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class path, preempting StackOverflowError.

解决：

<spark.scala.version>2.11</spark.scala.version>

<apache.kafka.version>0.9.0.1</apache.kafka.version>

<dependency>

    <groupId>org.apache.kafka</groupId>

    <artifactId>kafka_${spark.scala.version}</artifactId>

    <version>${apache.kafka.version}</version>

    <exclusions>

        <exclusion>

            <groupId>org.slf4j</groupId>

            <artifactId>slf4j-log4j12</artifactId>

        </exclusion>

        <exclusion>

            <groupId>log4j</groupId>

            <artifactId>log4j</artifactId>

        </exclusion>

    </exclusions>

</dependency>

原本文链接： https://yuzhouwan.com/posts/2254/

maven 高级玩法的相关教程结束。