Introduce additional JsonPath RequestMatchers in Spring MVC Test

Commit fffdd1e9e9 introduced additional
JsonPath result matchers in JsonPathResultMatchers for server-side
testing of MVC controllers.

This commit introduces comparable methods in JsonPathRequestMatchers
for client-side testing with a RestTemplate.

- isString()
- isBoolean()
- isNumber()
- isMap()

Issue: SPR-13320

spring-test/src/main/java/org/springframework/test/web/client/match/JsonPathRequestMatchers.java

@@ -115,6 +115,48 @@ public class JsonPathRequestMatchers {
 		};
 	}
 
+	/**
+	 * Evaluate the JSON path expression against the request content and
+	 * assert that the result is a {@link String}.
+	 * @since 4.2.1
+	 */
+	public RequestMatcher isString() {
+		return new AbstractJsonPathRequestMatcher() {
+			@Override
+			public void matchInternal(MockClientHttpRequest request) throws IOException, ParseException {
+				JsonPathRequestMatchers.this.jsonPathHelper.assertValueIsString(request.getBodyAsString());
+			}
+		};
+	}
+
+	/**
+	 * Evaluate the JSON path expression against the request content and
+	 * assert that the result is a {@link Boolean}.
+	 * @since 4.2.1
+	 */
+	public RequestMatcher isBoolean() {
+		return new AbstractJsonPathRequestMatcher() {
+			@Override
+			public void matchInternal(MockClientHttpRequest request) throws IOException, ParseException {
+				JsonPathRequestMatchers.this.jsonPathHelper.assertValueIsBoolean(request.getBodyAsString());
+			}
+		};
+	}
+
+	/**
+	 * Evaluate the JSON path expression against the request content and
+	 * assert that the result is a {@link Number}.
+	 * @since 4.2.1
+	 */
+	public RequestMatcher isNumber() {
+		return new AbstractJsonPathRequestMatcher() {
+			@Override
+			public void matchInternal(MockClientHttpRequest request) throws IOException, ParseException {
+				JsonPathRequestMatchers.this.jsonPathHelper.assertValueIsNumber(request.getBodyAsString());
+			}
+		};
+	}
+
 	/**
 	 * Evaluate the JSON path expression against the request content and
 	 * assert that the result is an array.
@@ -128,6 +170,20 @@ public class JsonPathRequestMatchers {
 		};
 	}
 
+	/**
+	 * Evaluate the JSON path expression against the request content and
+	 * assert that the result is a {@link java.util.Map}.
+	 * @since 4.2.1
+	 */
+	public RequestMatcher isMap() {
+		return new AbstractJsonPathRequestMatcher() {
+			@Override
+			public void matchInternal(MockClientHttpRequest request) throws IOException, ParseException {
+				JsonPathRequestMatchers.this.jsonPathHelper.assertValueIsMap(request.getBodyAsString());
+			}
+		};
+	}
+
 
 	/**
 	 * Abstract base class for {@code JsonPath}-based {@link RequestMatcher}s.