Add nohttp checkstyle rule

Closes gh-16682

spring-boot-parent/pom.xml

@@ -17,7 +17,7 @@
 		<url>https://www.spring.io</url>
 	</organization>
 	<properties>
-		<main.basedir>..</main.basedir>
+		<main.basedir>${basedir}/..</main.basedir>
 		<disable.checks>false</disable.checks>
 		<java.version>1.6</java.version>
 		<aether.version>1.0.2.v20150114</aether.version>
@@ -25,6 +25,7 @@
 		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 		<maven.version>3.1.1</maven.version>
 		<spring-javaformat.version>0.0.9</spring-javaformat.version>
+		<nohttp-checkstyle.version>0.0.1.RELEASE</nohttp-checkstyle.version>
 	</properties>
 	<scm>
 		<url>https://github.com/spring-projects/spring-boot</url>
@@ -318,6 +319,11 @@
 							<artifactId>spring-javaformat-checkstyle</artifactId>
 							<version>${spring-javaformat.version}</version>
 						</dependency>
+						<dependency>
+							<groupId>io.spring.nohttp</groupId>
+							<artifactId>nohttp-checkstyle</artifactId>
+							<version>${nohttp-checkstyle.version}</version>
+						</dependency>
 					</dependencies>
 				</plugin>
 				<plugin>
@@ -533,6 +539,8 @@
 							<configLocation>src/checkstyle/checkstyle.xml</configLocation>
 							<suppressionsLocation>src/checkstyle/checkstyle-suppressions.xml</suppressionsLocation>
 							<includeTestSourceDirectory>true</includeTestSourceDirectory>
+							<propertyExpansion>main.basedir=${main.basedir}</propertyExpansion>
+							<resourceIncludes>**\/*.*</resourceIncludes>
 						</configuration>
 						<goals>
 							<goal>check</goal>

spring-boot-parent/src/checkstyle/checkstyle-suppressions.xml

 <?xml version="1.0"?>
 <!DOCTYPE suppressions PUBLIC
-    "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
-    "https://checkstyle.org/dtds/suppressions_1_2.dtd">
+	"-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
+	"https://checkstyle.org/dtds/suppressions_1_2.dtd">
 <suppressions>
+<suppress files="[\\/]target[\\/]" checks=".*" />
+	<suppress files=".+\.[jar|git|ico|p12]" checks=".*" />
 	<suppress files="SpringApplicationTests\.java" checks="FinalClass" />
 	<suppress files=".+Configuration\.java" checks="HideUtilityClassConstructor" />
 	<suppress files=".+Application\.java" checks="HideUtilityClassConstructor" />

spring-boot-parent/src/checkstyle/checkstyle.xml

 <?xml version="1.0"?>
 <!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "https://checkstyle.org/dtds/configuration_1_2.dtd">
 <module name="com.puppycrawl.tools.checkstyle.Checker">
+	<module name="io.spring.nohttp.checkstyle.check.NoHttpCheck">
+		<property name="whitelistFileName" value="${main.basedir}/spring-boot-parent/src/checkstyle/nohttp-whitelist.txt"/>
+	</module>
 	<module name="io.spring.javaformat.checkstyle.SpringChecks" />
 	<module name="com.puppycrawl.tools.checkstyle.TreeWalker">
 		<module name="com.puppycrawl.tools.checkstyle.checks.imports.IllegalImportCheck">

spring-boot-parent/src/checkstyle/nohttp-whitelist.txt

+^http://livereload.com/protocols/official-7$

spring-boot-samples/pom.xml

@@ -20,6 +20,7 @@
 		<main.basedir>${basedir}/..</main.basedir>
 		<java.version>1.8</java.version>
 		<spring-javaformat.version>0.0.9</spring-javaformat.version>
+		<nohttp-checkstyle.version>0.0.1.RELEASE</nohttp-checkstyle.version>
 		<disable.checks>false</disable.checks>
 	</properties>
 	<modules>
@@ -155,6 +156,11 @@
 						<artifactId>spring-javaformat-checkstyle</artifactId>
 						<version>${spring-javaformat.version}</version>
 					</dependency>
+					<dependency>
+						<groupId>io.spring.nohttp</groupId>
+						<artifactId>nohttp-checkstyle</artifactId>
+						<version>${nohttp-checkstyle.version}</version>
+					</dependency>
 				</dependencies>
 				<executions>
 					<execution>
@@ -165,6 +171,8 @@
 							<configLocation>../spring-boot-parent/src/checkstyle/checkstyle.xml</configLocation>
 							<suppressionsLocation>../spring-boot-parent/src/checkstyle/checkstyle-suppressions.xml</suppressionsLocation>
 							<includeTestSourceDirectory>true</includeTestSourceDirectory>
+							<propertyExpansion>main.basedir=${main.basedir}</propertyExpansion>
+							<resourceIncludes>**\/*.*</resourceIncludes>
 						</configuration>
 						<goals>
 							<goal>check</goal>