[Java] spring cloud gateway 全局过滤器的实现

public interface globalfilter {
  mono<void> filter(serverwebexchange exchange, gatewayfilterchain chain);
}

@configuration
public class exampleconfiguration {
  private logger log = loggerfactory.getlogger(exampleconfiguration.class);
 
  @bean
  @order(-1)
  public globalfilter a() {
  return (exchange, chain) -> {
    log.info("first pre filter");
    return chain.filter(exchange).then(mono.fromrunnable(() -> {
    log.info("third post filter");
    }));
  };
  }
 
  @bean
  @order(0)
  public globalfilter b() {
  return (exchange, chain) -> {
    log.info("second pre filter");
    return chain.filter(exchange).then(mono.fromrunnable(() -> {
    log.info("second post filter");
    }));
  };
  }
 
  @bean
  @order(1)
  public globalfilter c() {
  return (exchange, chain) -> {
    log.info("third pre filter");
    return chain.filter(exchange).then(mono.fromrunnable(() -> {
    log.info("first post filter");
    }));
  };
  }
}

2018-10-14 12:08:52.406 info 55062 --- [ioeventloop-4-1] c.c.gateway.config.exampleconfiguration : first pre filter
2018-10-14 12:08:52.406 info 55062 --- [ioeventloop-4-1] c.c.gateway.config.exampleconfiguration : second pre filter
2018-10-14 12:08:52.407 info 55062 --- [ioeventloop-4-1] c.c.gateway.config.exampleconfiguration : third pre filter
2018-10-14 12:08:52.437 info 55062 --- [ctor-http-nio-7] c.c.gateway.config.exampleconfiguration : first post filter
2018-10-14 12:08:52.438 info 55062 --- [ctor-http-nio-7] c.c.gateway.config.exampleconfiguration : second post filter
2018-10-14 12:08:52.438 info 55062 --- [ctor-http-nio-7] c.c.gateway.config.exampleconfiguration : third post filter

@component
public class ipcheckfilter implements globalfilter, ordered {
 
  @override
  public int getorder() {
  return 0;
  }
 
  @override
  public mono<void> filter(serverwebexchange exchange, gatewayfilterchain chain) {
  httpheaders headers = exchange.getrequest().getheaders();
  // 此处写死了，演示用，实际中需要采取配置的方式
  if (getip(headers).equals("127.0.0.1")) {
    serverhttpresponse response = exchange.getresponse();
    responsedata data = new responsedata();
    data.setcode(401);
    data.setmessage("非法请求");
    byte[] datas = jsonutils.tojson(data).getbytes(standardcharsets.utf_8);
    databuffer buffer = response.bufferfactory().wrap(datas);
    response.setstatuscode(httpstatus.unauthorized);
    response.getheaders().add("content-type", "application/json;charset=utf-8");
    return response.writewith(mono.just(buffer));
  }
  return chain.filter(exchange);
  }
 
  // 这边从请求头中获取用户的实际ip,根据nginx转发的请求头获取
  private string getip(httpheaders headers) {
  return "127.0.0.1";
  }
 
}

exchange.getattributes().put(gateway_request_url_attr, requesturl);

uri requesturl = exchange.getrequiredattribute(gateway_request_url_attr);

@component
public class debugfilter implements globalfilter, ordered {
 
  @override
  public int getorder() {
  return 10101;
  }
 
  @override
  public mono<void> filter(serverwebexchange exchange, gatewayfilterchain chain) {
  try {
    exchange.getattributes().put(gateway_request_url_attr, new uri("http://192.168.31.245:8081/house/hello2"));
  } catch (urisyntaxexception e) {
    e.printstacktrace();
  }
  return chain.filter(exchange);
  }
 
}