springcloud-1: 用官方的pom.xml配置添加依赖失败

在eclipse中用STS生成了一个springcloud应用，pom.xml的核心配置如下：

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.0.RELEASE</version>
</parent>
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Finchley.M9</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>
<dependencies>
    <dependency>
        <groupId></groupId>
        <artifactId>spring-cloud-starter-config</artifactId>
    </dependency>
    <dependency>
        <groupId></groupId>
        <artifactId>spring-cloud-starter-eureka</artifactId>
    </dependency>
</dependencies><repositories>
    <repository>
        <id>spring-milestones</id>
        <name>Spring Milestones</name>
        <url>https://repo.spring.io/libs-milestone</url>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
    </repository>
</repositories>

用mvn install命令，报错如下：

[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[ERROR] Non-resolvable import POM: Could not transfer artifact org.springframework.cloud:spring-cloud-dependencies:pom:Finchley.M9 from/to spring-milestones (https://repo.spring.io/milestone): sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target @ line 43, column 16
[ERROR] 'dependencies.dependency.version' for org.springframework.cloud:spring-cloud-starter-netflix-eureka-server:jar is missing. @ line 29, column 15
 @
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]
[ERROR]   The project net.common:eureka-server:1.0.0 (D:developworkspaceeureka-serverpom.xml) has 2 errors
[ERROR]     Non-resolvable import POM: Could not transfer artifact org.springframework.cloud:spring-cloud-dependencies:pom:Finchley.M9 from/to spring-milestones (https://repo.spring.io/milestone): sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target @ line 43, column 16 -> [Help 2]
[ERROR]     'dependencies.dependency.version' for org.springframework.cloud:spring-cloud-starter-netflix-eureka-server:jar is missing. @ line 29, column 15
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException
[ERROR] [Help 2] http://cwiki.apache.org/confluence/display/MAVEN/UnresolvableModelException

报的错误挺玄乎，好像和SSL有关，实际上就是说目标文件找不到。

经多方查找和测试，pom.xml中repositories改成如下，解决问题：

<repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>repository.springframework.maven.release</id>
            <name>Spring Framework Maven Release Repository</name>
            <url>http://maven.springframework.org/milestone/</url>
        </repository>
        <repository>
            <id>org.springframework</id>
            <url> http://maven.springframework.org/snapshot</url>
        </repository>
        <repository>
            <id>spring-milestone</id>
            <name>Spring Maven MILESTONE Repository</name>
            <url>http://repo.spring.io/libs-milestone</url>
        </repository>
        <repository>
            <id>spring-release</id>
            <name>Spring Maven RELEASE Repository</name>
            <url>http://repo.spring.io/libs-release</url>
        </repository>
    </repositories>