Support escaped characters in BasicJsonParser

This commit adds the ability to have escaped characters, like the quote,
when using the BasicJsonParser. It also adds a short test for escaped
quotes.

Closes gh-14521

Author: ncharlton02

spring-boot/src/main/java/org/springframework/boot/json/BasicJsonParser.java

@@ -125,9 +125,16 @@ private List<String> tokenize(String json) {
 		int inObject = 0;
 		int inList = 0;
 		boolean inValue = false;
+		boolean inEscape = false;
 		StringBuilder build = new StringBuilder();
 		while (index < json.length()) {
 			char current = json.charAt(index);
+			if (inEscape) {
+				build.append(current);
+				index++;
+				inEscape = false;
+				continue;
+			}
 			if (current == '{') {
 				inObject++;
 			}
@@ -147,6 +154,9 @@ private List<String> tokenize(String json) {
 				list.add(build.toString());
 				build.setLength(0);
 			}
+			else if (current == '\\') {
+				inEscape = true;
+			}
 			else {
 				build.append(current);
 			}

spring-boot/src/test/java/org/springframework/boot/json/AbstractJsonParserTests.java

@@ -170,4 +170,11 @@ public void listWithLeadingWhitespaceMapThrowsARuntimeException() {
 		this.parser.parseList("\n\t{}");
 	}
 
+	@Test
+	public void escapeQuote() {
+		String input = "{\"foo\": \"\\\"bar\\\"\"}";
+		Map<String, Object> map = this.parser.parseMap(input);
+		assertThat(map.get("foo")).isEqualTo("\"bar\"");
+	}
+
 }