一、spring的maven中心库
releases：
<repositories>
<repository>
<id>io.spring.repo.maven.release</id>
<url>http://repo.spring.io/release/</url>
<snapshots><enabled>false</enabled></snapshots>
</repository>
</repositories>
milestones:
<repositories>
<repository>
<id>io.spring.repo.maven.snapshot</id>
<url>http://repo.spring.io/snapshot/</url>
<snapshots><enabled>true</enabled></snapshots>
</repository>
</repositories>
snapshots:
<repositories>
<repository>
<id>io.spring.repo.maven.milestone</id>
<url>http://repo.spring.io/milestone/</url>
<snapshots><enabled>false</enabled></snapshots>
</repository>
</repositories>
二、添加"Bill Of Materials"
因为经常你有可能弄不清楚或者忘记了spring的版本号依赖，所以你通过“物料清单”帮你管理依赖关系，引入物料清单
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-framework-bom</artifactId>
<version>4.2.5.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
引入物料清单之后，你引入的spring就不需要带版本号了
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</dependency>
</dependencies>
