Changes default of StripPrefix filter from 0 to 1.

Fixes gh-2033

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/StripPrefixGatewayFilterFactory.java

@@ -96,7 +96,7 @@ public class StripPrefixGatewayFilterFactory
 
 	public static class Config {
 
-		private int parts;
+		private int parts = 1;
 
 		public int getParts() {
 			return parts;

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/factory/StripPrefixGatewayFilterFactoryIntegrationTests.java

@@ -38,10 +38,15 @@ import static org.springframework.boot.test.context.SpringBootTest.WebEnvironmen
 public class StripPrefixGatewayFilterFactoryIntegrationTests extends BaseWebClientTests {
 
 	@Test
-	public void stripPrefixFilterDefaultValuesWork() {
+	public void stripPrefixFilterStripMultiplePartsValuesWork() {
 		testClient.get().uri("/foo/bar/get").header("Host", "www.stripprefix.org").exchange().expectStatus().isOk();
 	}
 
+	@Test
+	public void stripPrefixFilterDefaultPartsWork() {
+		testClient.get().uri("/foo/get").header("Host", "www.stripprefixdefault.org").exchange().expectStatus().isOk();
+	}
+
 	@EnableAutoConfiguration
 	@SpringBootConfiguration
 	@Import(DefaultTestConfig.class)

spring-cloud-gateway-server/src/test/resources/application.yml

@@ -429,6 +429,15 @@ spring:
         filters:
           - StripPrefix=2
 
+        # =====================================
+      - id: strip_prefix_default_test
+        uri: ${test.uri}
+        predicates:
+          - Host=**.stripprefixdefault.org
+          - Path=/foo/**
+        filters:
+          - StripPrefix
+
       # =====================================
       - id: rewrite_path_test
         uri: ${test.uri}