账户登录时，要求一个账户同时只能一人登录，配置中的步骤有三个：
1.在web.xml中配置HttpSessionEventPublisher
<listener> <listener-class>org.springframework.security.web.session.HttpSessionEventPublisher</listener-class> </listener>
2.在security.xml中配置session management
session-management标签放在http标签中
<session-management invalid-session-url="/login?invalid_session"> <concurrency-control max-sessions="1" error-if-maximum-exceeded="false" expired-url="/login?expired"/> </session-management>
其中的"max-session"属性表示最大session会话数量，默认是1;"error-if-maximum-exceeded"属性默认是false,表示同一账号，先登录的，会被后登录者强制下线，为true时，表示一旦有用户登录，其他用户将无法登录。
3.重写user登录相关类中的equals和hashCode方法，若扩展了UserDetails，也要重写其equals和hashCode方法
User.java
@Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof User)) return false; User that = (User) o; if (guid != null ? !guid.equals(that.guid) : that.guid != null) return false; return true; } @Override public int hashCode() { return guid != null ? guid.hashCode() : 0; }
StUserDetails.java
@Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof StUserDetails)) return false; StUserDetails that = (StUserDetails) o; if (grantedAuthorities != null ? !grantedAuthorities.equals(that.grantedAuthorities) : that.grantedAuthorities != null) return false; if (user != null ? !user.equals(that.user) : that.user != null) return false; return true; } @Override public int hashCode() { int result = user != null ? user.hashCode() : 0; result = 31 * result + (grantedAuthorities != null ? grantedAuthorities.hashCode() : 0); return result; }