如何修复访问部署在Tomcat上的restful spring-boot应用程序的IlleagalstateExcept

Question

我越来越threw exception java.lang.IllegalStateException: getWriter() has already been called for this response at org.apache.catalina.connector.Response.getOutputStream(Response.java:544)

同时从 angular2 传达我的服务器端代码(RESTFul，Spring-boot(。两者都部署在同一台服务器上 (Tomcat 8.0.2(。

以下是我的代码

@RequestMapping(value="/login", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
public User login() {
Object principal = SecurityContextHolder.getContext().getAuthentication().getPrincipal();
User user = (User) principal;
return user;
}

如何解决这个问题？

Answer 1

更改 ：

@RequestMapping(value="/login", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
public User login(Principal principal) {
User user = (User) principal; // take care of the conversion!
return user;
}

或

@RequestMapping(value="/login", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
public User login(Authentication authentication) {
User user = (User) authentication.getPrincipal(); // take care of the conversion!
return user;
}