安装完WebCenter后，发现访问WebLogic Server EM报“Error 503--Service Unavailable”错误，错误信息如下： Error 503--Service Unavailable From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1 : 10.5.4 503 Service Unavailable The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay may be indicated in a Retry-After header. If no Retry-After is given, the client SHOULD handle the response as it would for a 500 response. Note: The existence of the 503 status code does not imply that a server must use it when becoming overloaded. Some servers may wish to simply refuse the connection. 查找了一下原因，发现因为是$MW_HOME/user_projects/domains/<your_domain>/sysman/state/targets.xml文件丢失引起的，解决步骤如下： 1.备份旧的targets.xml文件； 2.按以下模板修改targets.xml文件 <Target TYPE="oracle_ias_farm" NAME="Farm_%DOMAIN-NAME%" DI...