是由过滤器SecurityContextPersistenceFilter 完成的,核心代码如下
代码语言：javascript复制public class SecurityContextPersistenceFilter extends GenericFilterBean {
static final String FILTER_APPLIED = "__spring_security_scpf_applied";
private SecurityContextRepository repo;
private boolean forceEagerSessionCreation = false;
public SecurityContextPersistenceFilter() {
this(new HttpSessionSecurityContextRepository());
}
public SecurityContextPersistenceFilter(SecurityContextRepository repo) {
this.repo = repo;
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
doFilter((HttpServletRequest) request, (HttpServletResponse) response, chain);
}
private void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
throws IOException, ServletException {
// ensure that filter is only applied once per request
if (request.getAttribute(FILTER_APPLIED) != null) {
chain.doFilter(request, response);
return;
}
request.setAttribute(FILTER_APPLIED, Boolean.TRUE);
if (this.forceEagerSessionCreation) {
HttpSession session = request.getSession();
if (this.logger.isDebugEnabled() && session.isNew()) {
this.logger.debug(LogMessage.format("Created session %s eagerly", session.getId()));
}
}
HttpRequestResponseHolder holder = new HttpRequestResponseHolder(request, response);
// 获取用户信息
SecurityContext contextBeforeChainExecution = this.repo.loadContext(holder);
try {
//用户信息绑定到线程
SecurityContextHolder.setContext(contextBeforeChainExecution);
if (contextBeforeChainExecution.getAuthentication() == null) {
logger.debug("Set SecurityContextHolder to empty SecurityContext");
}
else {
if (this.logger.isDebugEnabled()) {
this.logger
.debug(LogMessage.format("Set SecurityContextHolder to %s", contextBeforeChainExecution));
}
}
chain.doFilter(holder.getRequest(), holder.getResponse());
}
finally {
SecurityContext contextAfterChainExecution = SecurityContextHolder.getContext();
// Crucial removal of SecurityContextHolder contents before anything else.
SecurityContextHolder.clearContext();
this.repo.saveContext(contextAfterChainExecution, holder.getRequest(), holder.getResponse());
request.removeAttribute(FILTER_APPLIED);
this.logger.debug("Cleared SecurityContextHolder to complete request");
}
}
public void setForceEagerSessionCreation(boolean forceEagerSessionCreation) {
this.forceEagerSessionCreation = forceEagerSessionCreation;
}
}
