爲何要學習這個技術?html
咱們目前用來就是方便導入jar包的!
Maven的核心思想:約定大於配置
- 有約定,不要去違反.java
Maven會規定好如何去編寫咱們的java代碼,必需要按照這個規範來;web
官網:https://maven.apache.org/apache
下載完成後,解壓便可:tomcat
在咱們的系統環境變量中
配置錄下配置:架構
- 鏡像:mirrors - 做用:加速咱們的下載 - 國內建議使用阿里雲的鏡像 confi/settings.xml-->149行
<mirror> <id>nexus-aliyun</id> <mirrorOf>*,!jeecg,!jeecg-snapshots</mirrorOf> <name>Nexus aliyun</name> <url>http://maven.aliyun.com/nexus/content/groups/public</url> </mirror>
在本地的倉庫,遠程倉庫
創建一個倉庫: localRepository` settings.xml 55行app
<localRepository>D:\Program Files\maven\apache-maven-3.8.1\maven-repo</localRepository>
3. 等待項目構建
4. 觀察Maven倉庫中多了什麼東西
5. IDEA中的Mavne設置webapp
這個只有在web應用下才會有!
maven
,ide
爲何會有這個問題:咱們訪問一個網址,須要指定一個文件夾名字;
啓動Tomcat
pom.xml是Maven的核心配置文件
<?xml version="1.0" encoding="UTF-8"?> <!--Maven版本和頭文件--> <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> <!-- 這裏就是咱們剛剛配置的GAN--> <groupId>com.xianyudoufu</groupId> <artifactId>javaweb-01-maven</artifactId> <version>1.0-SNAPSHOT</version> <!-- package:項目的打包方式 jar:java應用 war:javaweb應用 --> <packaging>war</packaging> <!--配置--> <properties> <!-- 項目的默認構建編碼--> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <!-- 編譯版本--> <maven.compiler.source>1.7</maven.compiler.source> <maven.compiler.target>1.7</maven.compiler.target> </properties> <!--項目依賴--> <dependencies> <!-- 具體依賴的jar包文件--> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <!-- 做用域 --> <scope>test</scope> <!-- 生產--> //#<scope>provided</scope> </dependency> </dependencies> <!--項目構建用的東西--> <build> <finalName>javaweb-01-maven</finalName> <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --> <plugins> <plugin> <artifactId>maven-clean-plugin</artifactId> <version>3.1.0</version> </plugin> <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging --> <plugin> <artifactId>maven-resources-plugin</artifactId> <version>3.0.2</version> </plugin> <plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.0</version> </plugin> <plugin> <artifactId>maven-surefire-plugin</artifactId> <version>2.22.1</version> </plugin> <plugin> <artifactId>maven-war-plugin</artifactId> <version>3.2.2</version> </plugin> <plugin> <artifactId>maven-install-plugin</artifactId> <version>2.5.2</version> </plugin> <plugin> <artifactId>maven-deploy-plugin</artifactId> <version>2.8.2</version> </plugin> </plugins> </pluginManagement> </build> </project>
maven因爲他的約定大於配置,咱們以後可能會遇到咱們寫的配置文件,沒法被導出或者生效的問題,解決方案:
<!-- 在build中配置resources,來防止咱們資源導出失敗的問題--> <build> <resources> <resource> <directory>src/main/resources</directory> <excludes> <exclude>**/*.properties</exclude> <exclude>**/*.xml</exclude> </excludes> <filtering>false</filtering> </resource> <resource> <directory>src/main/java</directory> <includes> <include>**/*.properties</include> <include>**/*.xml</include> </includes> <filtering>false</filtering> </resource> </resources> </build>
maven中jar包的聯繫關聯圖
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0" metadata-complete="true"> </web-app>