SpringCloudGateway--谓词（断言）

目录

一、定义

二、谓词使用

1、After

2、Before

3、Between

4、Cookie

5、Header

6、Host

7、Method

8、Path

9、Query 

10、RemoteAddr

11、Weight

---

一、定义

        SpringCloudGateway中三个重要词汇：

        路由（Route）：配置网关中的一个完整路由，包括命名，地址，谓词集合（规则），过滤器集合。

        谓词、断言（Predicate）：这是一个 Java 8 函数谓词。输入类型是一个 Spring 框架的 ServerWebExchange。这允许开发人员匹配来自 HTTP 请求的任何内容，例如头部或参数。简单说就是看发送的请求url中是否符合谓词中的规则，符合就通过，不符合就进行拦截。

        过滤器（Filter）：这些是 Spring 框架网关过滤器在特定工厂中构建的实例。这里，可以在发送下游请求之前或之后修改请求和响应。简单说就是负责在代理服务之前或是之后做的一些事情。

二、谓词使用

        Gateway中有很多已经实现好的谓词，可以查看GatewayPredicate下的实现类：

        接下来单独用这11个实现类举例，Gateway项目可以参考：SpringCloudGateway--自动路由映射与手动路由映射_雨欲语的博客-CSDN博客

1、After

        在指定时间之后，顾名思义就是只有在指定时间之后的请求才会生效：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
      - After=2022-11-26T00:00:00.000+08:00[Asia/Shanghai]
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

        进入AfterRoutePredicateFactory实现里面，可以看到是由工厂方法加匿名内部类实现：

        在SpringCloudGateway中可以找到加载这些实现类的工厂方法：

        其余的实现类也是同理 

2、Before

        指定时间之前,只有在指定时间之前的请求才会生效：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
      - Before=2022-11-26T00:00:00.000+08:00[Asia/Shanghai]
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

      

package org.springframework.cloud.gateway.handler.predicate;

import java.time.ZonedDateTime;
import java.util.Collections;
import java.util.List;
import java.util.function.Predicate;

import org.springframework.web.server.ServerWebExchange;

/**
 * @author Spencer Gibb
 */
public class BeforeRoutePredicateFactory extends AbstractRoutePredicateFactory<BeforeRoutePredicateFactory.Config> {

	/**
	 * DateTime key.
	 */
	public static final String DATETIME_KEY = "datetime";

	public BeforeRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Collections.singletonList(DATETIME_KEY);
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange serverWebExchange) {
				final ZonedDateTime now = ZonedDateTime.now();
				return now.isBefore(config.getDatetime());
			}

			@Override
			public String toString() {
				return String.format("Before: %s", config.getDatetime());
			}
		};
	}

	public static class Config {

		private ZonedDateTime datetime;

		public ZonedDateTime getDatetime() {
			return datetime;
		}

		public void setDatetime(ZonedDateTime datetime) {
			this.datetime = datetime;
		}

	}

}

3、Between

        需要在设定的时间范围之内才能进行请求转发：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
      - Between=2022-11-26T00:00:00.000+08:00[Asia/Shanghai],2022-11-30T00:00:00.000+08:00[Asia/Shanghai]
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

        源码：

package org.springframework.cloud.gateway.handler.predicate;

import java.time.ZonedDateTime;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

import javax.validation.constraints.NotNull;

import org.springframework.util.Assert;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

/**
 * @author Spencer Gibb
 */
public class BetweenRoutePredicateFactory extends AbstractRoutePredicateFactory<BetweenRoutePredicateFactory.Config> {

	/**
	 * DateTime 1 key.
	 */
	public static final String DATETIME1_KEY = "datetime1";

	/**
	 * DateTime 2 key.
	 */
	public static final String DATETIME2_KEY = "datetime2";

	public BetweenRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList(DATETIME1_KEY, DATETIME2_KEY);
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		Assert.isTrue(config.getDatetime1().isBefore(config.getDatetime2()),
				config.getDatetime1() + " must be before " + config.getDatetime2());

		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange serverWebExchange) {
				final ZonedDateTime now = ZonedDateTime.now();
				return now.isAfter(config.getDatetime1()) && now.isBefore(config.getDatetime2());
			}

			@Override
			public String toString() {
				return String.format("Between: %s and %s", config.getDatetime1(), config.getDatetime2());
			}
		};
	}

	@Validated
	public static class Config {

		@NotNull
		private ZonedDateTime datetime1;

		@NotNull
		private ZonedDateTime datetime2;

		public ZonedDateTime getDatetime1() {
			return datetime1;
		}

		public Config setDatetime1(ZonedDateTime datetime1) {
			this.datetime1 = datetime1;
			return this;
		}

		public ZonedDateTime getDatetime2() {
			return datetime2;
		}

		public Config setDatetime2(ZonedDateTime datetime2) {
			this.datetime2 = datetime2;
			return this;
		}

	}

}

4、Cookie

        要求请求中包含指定Cookie名和满足特定正则要求的值，Cookie必须有两个值，第一个Cookie包含的参数名，第二个表示参数对应的值，正则表达式：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Cookie=username,admin*
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

import javax.validation.constraints.NotEmpty;

import org.springframework.http.HttpCookie;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

/**
 * @author Spencer Gibb
 */
public class CookieRoutePredicateFactory extends AbstractRoutePredicateFactory<CookieRoutePredicateFactory.Config> {

	/**
	 * Name key.
	 */
	public static final String NAME_KEY = "name";

	/**
	 * Regexp key.
	 */
	public static final String REGEXP_KEY = "regexp";

	public CookieRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList(NAME_KEY, REGEXP_KEY);
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				List<HttpCookie> cookies = exchange.getRequest().getCookies().get(config.name);
				if (cookies == null) {
					return false;
				}
				for (HttpCookie cookie : cookies) {
					if (cookie.getValue().matches(config.regexp)) {
						return true;
					}
				}
				return false;
			}

			@Override
			public String toString() {
				return String.format("Cookie: name=%s regexp=%s", config.name, config.regexp);
			}
		};
	}

	@Validated
	public static class Config {

		@NotEmpty
		private String name;

		@NotEmpty
		private String regexp;

		public String getName() {
			return name;
		}

		public Config setName(String name) {
			this.name = name;
			return this;
		}

		public String getRegexp() {
			return regexp;
		}

		public Config setRegexp(String regexp) {
			this.regexp = regexp;
			return this;
		}

	}

}

5、Header

        表示请求头中必须包含的内容。

        注意：参数名和参数值之间依然使用逗号，参数值要使用正则表达式

        如果Header只有一个值表示请求头中必须包含的参数。如果有两个值，第一个表示请求头必须包含的参数名，第二个表示请求头参数对应值。

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Header=Connection,keep-alive
       - Header=Cache-Control,max-age=0
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.function.Predicate;

import javax.validation.constraints.NotEmpty;

import org.springframework.util.ObjectUtils;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

/**
 * @author Spencer Gibb
 */
public class HeaderRoutePredicateFactory extends AbstractRoutePredicateFactory<HeaderRoutePredicateFactory.Config> {

	/**
	 * Header key.
	 */
	public static final String HEADER_KEY = "header";

	/**
	 * Regexp key.
	 */
	public static final String REGEXP_KEY = "regexp";

	public HeaderRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList(HEADER_KEY, REGEXP_KEY);
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		boolean hasRegex = !ObjectUtils.isEmpty(config.regexp);

		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				List<String> values = exchange.getRequest().getHeaders().getOrDefault(config.header,
						Collections.emptyList());
				if (values.isEmpty()) {
					return false;
				}
				// values is now guaranteed to not be empty
				if (hasRegex) {
					// check if a header value matches
					for (int i = 0; i < values.size(); i++) {
						String value = values.get(i);
						if (value.matches(config.regexp)) {
							return true;
						}
					}
					return false;
				}

				// there is a value and since regexp is empty, we only check existence.
				return true;
			}

			@Override
			public String toString() {
				return String.format("Header: %s regexp=%s", config.header, config.regexp);
			}
		};
	}

	@Validated
	public static class Config {

		@NotEmpty
		private String header;

		private String regexp;

		public String getHeader() {
			return header;
		}

		public Config setHeader(String header) {
			this.header = header;
			return this;
		}

		public String getRegexp() {
			return regexp;
		}

		public Config setRegexp(String regexp) {
			this.regexp = regexp;
			return this;
		}

	}

}

6、Host

        匹配请求参数中Host参数的值，可以有多个，使用逗号隔开,**表示支持模糊匹配：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Host=127.0.0.1:8080,**.test.com
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;

import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.core.style.ToStringCreator;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.PathMatcher;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

/**
 * @author Spencer Gibb
 */
public class HostRoutePredicateFactory extends AbstractRoutePredicateFactory<HostRoutePredicateFactory.Config> {

	private PathMatcher pathMatcher = new AntPathMatcher(".");

	public HostRoutePredicateFactory() {
		super(Config.class);
	}

	public void setPathMatcher(PathMatcher pathMatcher) {
		this.pathMatcher = pathMatcher;
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Collections.singletonList("patterns");
	}

	@Override
	public ShortcutType shortcutType() {
		return ShortcutType.GATHER_LIST;
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				String host = exchange.getRequest().getHeaders().getFirst("Host");
				String match = null;
				for (int i = 0; i < config.getPatterns().size(); i++) {
					String pattern = config.getPatterns().get(i);
					if (pathMatcher.match(pattern, host)) {
						match = pattern;
						break;
					}
				}

				if (match != null) {
					Map<String, String> variables = pathMatcher.extractUriTemplateVariables(match, host);
					ServerWebExchangeUtils.putUriTemplateVariables(exchange, variables);
					return true;
				}

				return false;
			}

			@Override
			public String toString() {
				return String.format("Hosts: %s", config.getPatterns());
			}
		};
	}

	@Validated
	public static class Config {

		private List<String> patterns = new ArrayList<>();

		public List<String> getPatterns() {
			return patterns;
		}

		public Config setPatterns(List<String> patterns) {
			this.patterns = patterns;
			return this;
		}

		@Override
		public String toString() {
			return new ToStringCreator(this).append("patterns", patterns).toString();
		}

	}

}

7、Method

        Method表示请求方式。支持多个值，使用逗号分隔，多个值之间为or条件

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Method=GET,POST # 表示只允许GET or POST请求通过
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

import org.springframework.http.HttpMethod;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

import static java.util.Arrays.stream;

/**
 * @author Spencer Gibb
 * @author Dennis Menge
 */
public class MethodRoutePredicateFactory extends AbstractRoutePredicateFactory<MethodRoutePredicateFactory.Config> {

	/**
	 * Methods key.
	 */
	public static final String METHODS_KEY = "methods";

	public MethodRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList(METHODS_KEY);
	}

	@Override
	public ShortcutType shortcutType() {
		return ShortcutType.GATHER_LIST;
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				HttpMethod requestMethod = exchange.getRequest().getMethod();
				return stream(config.getMethods()).anyMatch(httpMethod -> httpMethod == requestMethod);
			}

			@Override
			public String toString() {
				return String.format("Methods: %s", Arrays.toString(config.getMethods()));
			}
		};
	}

	@Validated
	public static class Config {

		private HttpMethod[] methods;

		public HttpMethod[] getMethods() {
			return methods;
		}

		public void setMethods(HttpMethod... methods) {
			this.methods = methods;
		}

	}

}

8、Path

        请求url包含的路径，这种是使用得最多的一种,路径可以配置多个，用逗号隔开。

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Path=/service/**,/server/**
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.core.style.ToStringCreator;
import org.springframework.http.server.PathContainer;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.util.pattern.PathPattern;
import org.springframework.web.util.pattern.PathPattern.PathMatchInfo;
import org.springframework.web.util.pattern.PathPatternParser;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.putUriTemplateVariables;
import static org.springframework.http.server.PathContainer.parsePath;

/**
 * @author Spencer Gibb
 * @author Dhawal Kapil
 */
public class PathRoutePredicateFactory extends AbstractRoutePredicateFactory<PathRoutePredicateFactory.Config> {

	private static final Log log = LogFactory.getLog(PathRoutePredicateFactory.class);

	private static final String MATCH_TRAILING_SLASH = "matchTrailingSlash";

	private PathPatternParser pathPatternParser = new PathPatternParser();

	public PathRoutePredicateFactory() {
		super(Config.class);
	}

	private static void traceMatch(String prefix, Object desired, Object actual, boolean match) {
		if (log.isTraceEnabled()) {
			String message = String.format("%s \"%s\" %s against value \"%s\"", prefix, desired,
					match ? "matches" : "does not match", actual);
			log.trace(message);
		}
	}

	public void setPathPatternParser(PathPatternParser pathPatternParser) {
		this.pathPatternParser = pathPatternParser;
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList("patterns", MATCH_TRAILING_SLASH);
	}

	@Override
	public ShortcutType shortcutType() {
		return ShortcutType.GATHER_LIST_TAIL_FLAG;
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		final ArrayList<PathPattern> pathPatterns = new ArrayList<>();
		synchronized (this.pathPatternParser) {
			pathPatternParser.setMatchOptionalTrailingSeparator(config.isMatchTrailingSlash());
			config.getPatterns().forEach(pattern -> {
				PathPattern pathPattern = this.pathPatternParser.parse(pattern);
				pathPatterns.add(pathPattern);
			});
		}
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				PathContainer path = parsePath(exchange.getRequest().getURI().getRawPath());

				PathPattern match = null;
				for (int i = 0; i < pathPatterns.size(); i++) {
					PathPattern pathPattern = pathPatterns.get(i);
					if (pathPattern.matches(path)) {
						match = pathPattern;
						break;
					}
				}

				if (match != null) {
					traceMatch("Pattern", match.getPatternString(), path, true);
					PathMatchInfo pathMatchInfo = match.matchAndExtract(path);
					putUriTemplateVariables(exchange, pathMatchInfo.getUriVariables());
					return true;
				}
				else {
					traceMatch("Pattern", config.getPatterns(), path, false);
					return false;
				}
			}

			@Override
			public String toString() {
				return String.format("Paths: %s, match trailing slash: %b", config.getPatterns(),
						config.isMatchTrailingSlash());
			}
		};
	}

	@Validated
	public static class Config {

		private List<String> patterns = new ArrayList<>();

		private boolean matchTrailingSlash = true;

		public List<String> getPatterns() {
			return patterns;
		}

		public Config setPatterns(List<String> patterns) {
			this.patterns = patterns;
			return this;
		}

		/**
		 * @deprecated use {@link #isMatchTrailingSlash()}
		 */
		@Deprecated
		public boolean isMatchOptionalTrailingSeparator() {
			return isMatchTrailingSlash();
		}

		/**
		 * @deprecated use {@link #setMatchTrailingSlash(boolean)}
		 */
		@Deprecated
		public Config setMatchOptionalTrailingSeparator(boolean matchOptionalTrailingSeparator) {
			setMatchTrailingSlash(matchOptionalTrailingSeparator);
			return this;
		}

		public boolean isMatchTrailingSlash() {
			return matchTrailingSlash;
		}

		public Config setMatchTrailingSlash(boolean matchTrailingSlash) {
			this.matchTrailingSlash = matchTrailingSlash;
			return this;
		}

		@Override
		public String toString() {
			return new ToStringCreator(this).append("patterns", patterns)
					.append(MATCH_TRAILING_SLASH, matchTrailingSlash).toString();
		}

	}

}

9、Query 

        Query指请求参数，有两种，一种是必须包含参数名：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Query=username
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

        另外一种是设置参数的值，用正则匹配：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - Query=username,admin*
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

import javax.validation.constraints.NotEmpty;

import org.springframework.util.StringUtils;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

/**
 * @author Spencer Gibb
 */
public class QueryRoutePredicateFactory extends AbstractRoutePredicateFactory<QueryRoutePredicateFactory.Config> {

	/**
	 * Param key.
	 */
	public static final String PARAM_KEY = "param";

	/**
	 * Regexp key.
	 */
	public static final String REGEXP_KEY = "regexp";

	public QueryRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList(PARAM_KEY, REGEXP_KEY);
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				if (!StringUtils.hasText(config.regexp)) {
					// check existence of header
					return exchange.getRequest().getQueryParams().containsKey(config.param);
				}

				List<String> values = exchange.getRequest().getQueryParams().get(config.param);
				if (values == null) {
					return false;
				}
				for (String value : values) {
					if (value != null && value.matches(config.regexp)) {
						return true;
					}
				}
				return false;
			}

			@Override
			public String toString() {
				return String.format("Query: param=%s regexp=%s", config.getParam(), config.getRegexp());
			}
		};
	}

	@Validated
	public static class Config {

		@NotEmpty
		private String param;

		private String regexp;

		public String getParam() {
			return param;
		}

		public Config setParam(String param) {
			this.param = param;
			return this;
		}

		public String getRegexp() {
			return regexp;
		}

		public Config setRegexp(String regexp) {
			this.regexp = regexp;
			return this;
		}

	}

}

10、RemoteAddr

        允许访问的客户端地址，不能使用类似localhost这种：

routes: 
  - id: service-one 
    uri: lb://service-one
    predicates: 
       - RemoteAddr=127.0.0.1
    filters:
      - StripPrefix=1
    metadata:
      connect-timeout: 15000 #ms
      response-timeout: 15000 #ms

package org.springframework.cloud.gateway.handler.predicate;

import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.function.Predicate;

import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.NotNull;

import io.netty.handler.ipfilter.IpFilterRuleType;
import io.netty.handler.ipfilter.IpSubnetFilterRule;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.cloud.gateway.support.ipresolver.RemoteAddressResolver;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;

import static org.springframework.cloud.gateway.support.ShortcutConfigurable.ShortcutType.GATHER_LIST;

/**
 * @author Spencer Gibb
 */
public class RemoteAddrRoutePredicateFactory
		extends AbstractRoutePredicateFactory<RemoteAddrRoutePredicateFactory.Config> {

	private static final Log log = LogFactory.getLog(RemoteAddrRoutePredicateFactory.class);

	public RemoteAddrRoutePredicateFactory() {
		super(Config.class);
	}

	@Override
	public ShortcutType shortcutType() {
		return GATHER_LIST;
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Collections.singletonList("sources");
	}

	@NotNull
	private List<IpSubnetFilterRule> convert(List<String> values) {
		List<IpSubnetFilterRule> sources = new ArrayList<>();
		for (String arg : values) {
			addSource(sources, arg);
		}
		return sources;
	}

	@Override
	public Predicate<ServerWebExchange> apply(Config config) {
		List<IpSubnetFilterRule> sources = convert(config.sources);

		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				InetSocketAddress remoteAddress = config.remoteAddressResolver.resolve(exchange);
				if (remoteAddress != null && remoteAddress.getAddress() != null) {
					String hostAddress = remoteAddress.getAddress().getHostAddress();
					String host = exchange.getRequest().getURI().getHost();

					if (log.isDebugEnabled() && !hostAddress.equals(host)) {
						log.debug("Remote addresses didn't match " + hostAddress + " != " + host);
					}

					for (IpSubnetFilterRule source : sources) {
						if (source.matches(remoteAddress)) {
							return true;
						}
					}
				}

				return false;
			}

			@Override
			public String toString() {
				return String.format("RemoteAddrs: %s", config.getSources());
			}
		};
	}

	private void addSource(List<IpSubnetFilterRule> sources, String source) {
		if (!source.contains("/")) { // no netmask, add default
			source = source + "/32";
		}

		String[] ipAddressCidrPrefix = source.split("/", 2);
		String ipAddress = ipAddressCidrPrefix[0];
		int cidrPrefix = Integer.parseInt(ipAddressCidrPrefix[1]);

		sources.add(new IpSubnetFilterRule(ipAddress, cidrPrefix, IpFilterRuleType.ACCEPT));
	}

	@Validated
	public static class Config {

		@NotEmpty
		private List<String> sources = new ArrayList<>();

		@NotNull
		private RemoteAddressResolver remoteAddressResolver = new RemoteAddressResolver() {
		};

		public List<String> getSources() {
			return sources;
		}

		public Config setSources(List<String> sources) {
			this.sources = sources;
			return this;
		}

		public Config setSources(String... sources) {
			this.sources = Arrays.asList(sources);
			return this;
		}

		public Config setRemoteAddressResolver(RemoteAddressResolver remoteAddressResolver) {
			this.remoteAddressResolver = remoteAddressResolver;
			return this;
		}

	}

}

11、Weight

        负载均衡中权重：

routes:
  - id: service-one
    uri: lb://service-one
    predicates:
      - Weight=group,2
    filters: StripPrefix=1
  - id: service-two
    uri: lb://service-two
    predicates:
      - Weight=group,8
    filters: StripPrefix=1

package org.springframework.cloud.gateway.handler.predicate;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.cloud.gateway.event.WeightDefinedEvent;
import org.springframework.cloud.gateway.support.WeightConfig;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.web.server.ServerWebExchange;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_PREDICATE_ROUTE_ATTR;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.WEIGHT_ATTR;

/**
 * @author Spencer Gibb
 */
// TODO: make this a generic Choose out of group predicate?
public class WeightRoutePredicateFactory extends AbstractRoutePredicateFactory<WeightConfig>
		implements ApplicationEventPublisherAware {

	/**
	 * Weight config group key.
	 */
	public static final String GROUP_KEY = WeightConfig.CONFIG_PREFIX + ".group";

	/**
	 * Weight config weight key.
	 */
	public static final String WEIGHT_KEY = WeightConfig.CONFIG_PREFIX + ".weight";

	private static final Log log = LogFactory.getLog(WeightRoutePredicateFactory.class);

	private ApplicationEventPublisher publisher;

	public WeightRoutePredicateFactory() {
		super(WeightConfig.class);
	}

	@Override
	public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
		this.publisher = publisher;
	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Arrays.asList(GROUP_KEY, WEIGHT_KEY);
	}

	@Override
	public String shortcutFieldPrefix() {
		return WeightConfig.CONFIG_PREFIX;
	}

	@Override
	public void beforeApply(WeightConfig config) {
		if (publisher != null) {
			publisher.publishEvent(new WeightDefinedEvent(this, config));
		}
	}

	@Override
	public Predicate<ServerWebExchange> apply(WeightConfig config) {
		return new GatewayPredicate() {
			@Override
			public boolean test(ServerWebExchange exchange) {
				Map<String, String> weights = exchange.getAttributeOrDefault(WEIGHT_ATTR, Collections.emptyMap());

				String routeId = exchange.getAttribute(GATEWAY_PREDICATE_ROUTE_ATTR);

				// all calculations and comparison against random num happened in
				// WeightCalculatorWebFilter
				String group = config.getGroup();
				if (weights.containsKey(group)) {

					String chosenRoute = weights.get(group);
					if (log.isTraceEnabled()) {
						log.trace("in group weight: " + group + ", current route: " + routeId + ", chosen route: "
								+ chosenRoute);
					}

					return routeId.equals(chosenRoute);
				}
				else if (log.isTraceEnabled()) {
					log.trace("no weights found for group: " + group + ", current route: " + routeId);
				}

				return false;
			}

			@Override
			public String toString() {
				return String.format("Weight: %s %s", config.getGroup(), config.getWeight());
			}
		};
	}

}