Merge pull request #82 from networknt/issue81

fixes #81 Resolve an NPE issue in SanitizerMiddleware

Author: stevehu

src/main/java/com/networknt/aws/lambda/handler/middleware/sanitizer/SanitizerMiddleware.java

@@ -69,7 +69,7 @@ public Status execute(LightLambdaExchange exchange) {
 
         if (CONFIG.isBodyEnabled() && ("POST".equalsIgnoreCase(method) || "PUT".equalsIgnoreCase(method) || "PATCH".equalsIgnoreCase(method))) {
             String body = exchange.getRequest().getBody();
-            if (!body.isEmpty()) {
+            if (body != null && !body.isEmpty()) {
                 body = body.trim();
                 if (body.startsWith("{")) {
                     Map<String, Object> bodyMap = JsonMapper.string2Map(body);