Eclipse需要安装一个Jcoco的插件，但是连接Eclipse Market的时候，总是出现如下的报错：
Cannot open Eclipse Marketplace
Cannot install remote marketplace locations: Connection failed
This is most often caused by a problem with your internet connection. Please check your internet connection and retry.
Cannot complete request to http://marketplace.eclipse.org/catalogs/api/p: Unable to connect to repository http://marketplace.eclipse.org/catalogs/api/p
Unable to connect to repository http://marketplace.eclipse.org/catalogs/api/p
Connection to http://marketplace.eclipse.org refused
Connection failed
This is most often caused by a problem with your internet connection. Please check your internet connection and retry.
Connection to http://marketplace.eclipse.org refused
解决方案：
1、修改eclipse.ini文件，在文件末尾添加如下内容：
-Djava.net.preferIPv4Stack=true
2、通过安装插件的方式，手动添加Eclipse Market
点击 help->Install new SoftWare->add
输入插件名：Market Client
输入路径：http://download.eclipse.org/mpc/indigo/
添加完成后，选择Eclipse Marketplace Client,下载安装即可。