依赖范围
<dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency>
Compile：默认值。表示编译（compile）时需要，测试时需要，运行时需要，打包时需要。比如：struts2-core
Provided：编译（compile）时需要，测试（test）时也需要 ，运行时不需要，打包时不需要。比如 jsp-api.jar servlet-api.jar
Runtime：编译时不需要，测试时需要，，运行时需要，打包时需要。比如：数据库驱动包
Test：编译时不需要，测试时需要，运行时不需要，打包也不需要。比如：junit.jar
依赖传递
只添加了一个struts2-core依赖，发现项目中出现了很多jar，这种情况叫依赖传递。
<dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-core</artifactId> <version>2.3.24</version> </dependency>
在整合ssh框架的时候，添加struts2-spring-plugin包和spring-context包依赖时，spring-bean会出现版本冲突。
<dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-spring-plugin</artifactId> <version>2.3.24</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.2.4.RELEASE</version> </dependency>
依赖版本冲突的解决
1、第一声明优先原则，谁先定义的就优先使用谁的传递依赖。
<!-- spring-beans-4.2.4 --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.2.4.RELEASE</version> </dependency> <!-- spring-beans-3.0.5 --> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-spring-plugin</artifactId> <version>2.3.24</version> </dependency>
以上代码都包含对spring-beans的依赖，但是版本不同，我们要使用4.2.4的。
2、路径近者优先原则，直接依赖级别大于传递依赖。也就是自己添加jar包。
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>4.2.4.RELEASE</version> </dependency>
还是上面的代码都包含对spring-bean的依赖，我们也可以自己添加jar包，则会使用我们自己添加的。
3、排除原则，排除掉不想用的依赖。
<dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-spring-plugin</artifactId> <version>2.3.24</version> <exclusions> <exclusion> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> </exclusion> </exclusions> </dependency>
4、版本锁定原则，指定项目中用到依赖信息版本。
<!--抽取公用的版本--> <properties> <spring.version>4.2.4.RELEASE</spring.version> <hibernate.version>5.0.7.Final</hibernate.version> <struts.version>2.3.24</struts.version> </properties> <!-- 锁定版本，struts2-2.3.24、spring4.2.4、hibernate5.0.7 --> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> </dependencies> </dependencyManagement>
SSH框架整合，太耗时，百度ssh pom即可。
完善pom.xml文件，把ssh相关的依赖都添加上去，大体如下：
<!-- 属性 --> <properties> <spring.version>4.2.4.RELEASE</spring.version> <hibernate.version>5.0.7.Final</hibernate.version> <struts.version>2.3.24</struts.version> </properties> <!-- 锁定版本，struts2-2.3.24、spring4.2.4、hibernate5.0.7 --> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-core</artifactId> <version>${struts.version}</version> </dependency> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-spring-plugin</artifactId> <version>${struts.version}</version> </dependency> </dependencies> </dependencyManagement> <!-- 依赖管理 --> <dependencies> <!-- spring --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> </dependency> <!-- hibernate --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> </dependency> <!-- 数据库驱动 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.6</version> <scope>runtime</scope> </dependency> <!-- c3p0 --> <dependency> <groupId>c3p0</groupId> <artifactId>c3p0</artifactId> <version>0.9.1.2</version> </dependency> <!-- 导入 struts2 --> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-core</artifactId> </dependency> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-spring-plugin</artifactId> </dependency> <!-- servlet jsp --> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jsp-api</artifactId> <version>2.0</version> <scope>provided</scope> </dependency> <!-- 日志 --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.7.2</version> </dependency> <!-- junit --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.9</version> <scope>test</scope> </dependency> <!-- jstl --> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> </dependencies> <build> <plugins> <!-- 设置编译版本为1.8 --> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.8</source> <target>1.8</target> <encoding>UTF-8</encoding> </configuration> </plugin> <!-- maven内置 的tomcat6插件 --> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>tomcat-maven-plugin</artifactId> <version>1.1</version> <configuration> <!-- 可以灵活配置工程路径 --> <path>/ssh</path> <!-- 可以灵活配置端口号 --> <port>8080</port> </configuration> </plugin> </plugins> </build>
学习资源：http://www.cnblogs.com/xdp-gacl/tag/Maven%E5%AD%A6%E4%B9%A0%E6%80%BB%E7%BB%93/