使用方式
建立一個過濾器繼承ZuulFilter,實作ZuulFilter中的抽象方法,并将定義的類添加到spring容器中。
代碼:
import com.google.common.util.concurrent.RateLimiter;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import org.springframework.cloud.netflix.zuul.filters.support.FilterConstants;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
@Component
public class RateFilter extends ZuulFilter {
private static int count=0;
//設定每秒釋放的令牌數量
private static final RateLimiter rateLimiter = RateLimiter.create(1);
@Override
public String filterType() {
//指定該類過濾器為pre類型
return FilterConstants.PRE_TYPE;
}
@Override
public int filterOrder() {
//設定執行過濾器的執行順序,數值小,優先執行
return -11;
}
@Override
public boolean shouldFilter() {
//判斷是否執行該過濾器;false:不執行;true:執行
return true;
}
@Override
public Object run() throws ZuulException {
//處理過濾器具體業務邏輯的地方
RequestContext requestContext = RequestContext.getCurrentContext();
Boolean flag = true;
//int i= 1/0;
//判斷是否擷取令牌
if(!rateLimiter.tryAcquire()){
flag = false;
System.out.println("未拿到令牌,限流中:count="+count++);
requestContext.setSendZuulResponse(false);
requestContext.setResponseStatusCode(HttpStatus.TOO_MANY_REQUESTS.value());
requestContext.setResponseBody("未擷取到令牌請重試!");
}
requestContext.set("f",flag);
return null;
}
}
PS:這是一個前置過濾器,用來實作限流功能。