如何在Spring Boot Filter中获取和设置响应体

Question

@RestController
public class XxxController {

    public void ResponseEntity(ClientRequest clientRequest) {
         ...
         return ResponseEntity.ok(clientResponse);
    }
}

@Component
public class MyClassFilter implements Filter {


    @Override
    public void doFilter( HttpServletRequest req,  HttpServletResponse res, FilterChain chain) throws IOException, ServletException {
 
    }

    @Override
    public void destroy() {}

    @Override
    public void init(FilterConfig arg0) throws ServletException {}

}

Answer 1

不确定在过滤器中获得响应是什么意思。在筛选器中，请求尚未传递给控制器，因此还没有响应。不过你可以得到请求。但是请注意不要读取请求，因为在这种情况下，请求流将在过滤器中读取，当它到达控制器时，整个请求流将已经被读取。若要设置响应，可以执行以下操作：

protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
    response.resetBuffer();
    response.setStatus(HttpStatus.OK);
    response.setHeader(HttpHeaders.CONTENT_TYPE, "application/json");
    response.getOutputStream().print(new ObjectMapper().writeValueAsString(myData));
    response.flushBuffer(); // marks response as committed -- if we don't do this the request will go through normally!
}

您可以在这里看到为什么必须刷新响应。您还可以执行senderrorHttpServletResponse#senderror如何更改ContentType

如果不刷新响应，则请求将继续沿着筛选器链向下（必须添加chain.dofilter(request,response）；当然！）。