Mac上 eclipse配置jdk8
1.下载jdk8，安装，默认路径是/Library/Java/JavaVirtualMachines
2. properties-Java build path - edit/add library
3. 如果是add library，选择jre system library，进到下图 Select JRE for the project build path.页面
4.installed jre
5.注意：路径一定要选对，是jdk的安装路径，/Library/Java/JavaVirtualMachines/jdk1.8.0_201.jdk/Contents/Home目录下
7.finish
8.再回去选择，刚刚安装的jdk就显示了-finish