安装tomcat8首先要配置好JdK和Tomcat8的环境变量（可自行百度参考）
其次在Myeclipse中关联Tomcat8是需要是JDK8也配置上去（在Servers–》Tomcat8–>JDK）配置JDK1.8上去，不然会报错。
遇到严重: Failed to open access log file [C:\Program Files\Apache Software Foundation\Tomcat 7.0\logs\localhost_access_log.2015-01-21.txt]
java.io.FileNotFoundException: C:\Program Files\Apache Software Foundation\Tomcat 8.0\logs\localhost_access_log.2015-01-21.txt (拒绝访问。)
解决：