[Java] springboot zuul实现网关的代码

• 统一授权
  
• 统一异常处理
  
• 路由导向
  
• 跨域处理
  
• 限流
  

dependencies {
  implementation('org.springframework.cloud:spring-cloud-starter-netflix-eureka-client')
  implementation('org.springframework.cloud:spring-cloud-starter-netflix-zuul')
  testimplementation('org.springframework.boot:spring-boot-starter-test')
  implementation('com.marcosbarbero.cloud:spring-cloud-zuul-ratelimit:1.3.2.release')
}

server:
 port: 8300
spring:
 application:
  name: microservice-gateway-zuul
eureka:
 client:
  register-with-eureka: true
  fetch-registry: true
  service-url:
   defaultzone: http://localhost:6761/eureka
 instance:
  ip-address: true
zuul:
 routes:
  users:
  path: /lind/** #以lind开头的路径被重定向到lind服务
  serviceid: lind
 add-host-header: true #显示真实的http头
 retryable: false #关闭hystrix的重试功能
 ratelimit:
  enabled: true
  # repository: redis
  behind-proxy: true
  policies:
  users:
   limit: 5 #限流，每分钟请求5次
   refresh-interval: 60
   type:
    - user
    - origin
    - url
   #  url类型的限流就是通过请求路径区分
   #  origin是通过客户端ip地址区分
   #  user是通过授权用户进行区分，也包括匿名用户

public class prerequestlogfilter extends zuulfilter {
 private static final logger logger = loggerfactory.getlogger(prerequestlogfilter.class);
 private final ratelimiter ratelimiter = ratelimiter.create(1000.0);
 @override
 public object run() {
  try {
   requestcontext currentcontext = requestcontext.getcurrentcontext();
   httpservletresponse response = currentcontext.getresponse();
   httpservletrequest reqeust = currentcontext.getrequest();
   currentcontext.addzuulrequestheader("userid","123");//向子系统http头写数据
   currentcontext.addzuulrequestheader("username","test");
   prerequestlogfilter.logger.info(
   string.format("send %s request to %s",
     reqeust.getmethod(),
     reqeust.getrequesturl().tostring()));
   if (!ratelimiter.tryacquire()) {
  httpstatus httpstatus = httpstatus.too_many_requests;
  response.setcontenttype(mediatype.text_plain_value);
  response.setstatus(httpstatus.value());
  response.getwriter().append(httpstatus.getreasonphrase());
  currentcontext.setsendzuulresponse(false);
  throw new zuulexception(
    httpstatus.getreasonphrase(),
    httpstatus.value(),
    httpstatus.getreasonphrase()
  );
   }
  } catch (java.lang.exception e) {
   reflectionutils.rethrowruntimeexception(e);
  }
  return null;
 }
 @override
 public boolean shouldfilter() {
  // 判断是否需要过滤
  return true;
 }
 @override
 public string filtertype() {
  return filterconstants.pre_type;
 }
 @override
 public int filterorder() {
  return ordered.highest_precedence;
 }
}

@bean
 public prerequestlogfilter prerequestlogfilter() {
  return new prerequestlogfilter();
 }