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/