Addressed duplicate parameters bug reported in #86 and added unit test for it.

Author: sapessi

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletRequest.java

@@ -88,13 +88,7 @@ public class AwsProxyHttpServletRequest extends AwsHttpServletRequest {
     //-------------------------------------------------------------
 
     public AwsProxyHttpServletRequest(AwsProxyRequest awsProxyRequest, Context lambdaContext, SecurityContext awsSecurityContext) {
-        super(lambdaContext);
-        this.request = awsProxyRequest;
-        this.securityContext = awsSecurityContext;
-        this.config = ContainerConfig.defaultConfig();
-
-        this.urlEncodedFormParameters = getFormUrlEncodedParametersMap();
-        this.multipartFormParameters = getMultipartFormParametersMap();
+        this(awsProxyRequest, lambdaContext, awsSecurityContext, ContainerConfig.defaultConfig());
     }
 
     public AwsProxyHttpServletRequest(AwsProxyRequest awsProxyRequest, Context lambdaContext, SecurityContext awsSecurityContext, ContainerConfig config) {
@@ -506,7 +500,7 @@ public Map<String, String[]> getParameterMap() {
 
         if (request.getQueryStringParameters() != null) {
             for (Map.Entry<String, String> entry : request.getQueryStringParameters().entrySet()) {
-                if (params.containsKey(entry.getKey())) {
+                if (params.containsKey(entry.getKey()) && !params.get(entry.getKey()).contains(entry.getValue())) {
                     params.get(entry.getKey()).add(entry.getValue());
                 } else {
                     List<String> valueList = new ArrayList<>();

aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletRequestTest.java

@@ -11,6 +11,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import static org.junit.Assert.*;
 
@@ -42,6 +43,9 @@ public class AwsProxyHttpServletRequestTest {
             .cookie(FORM_PARAM_TEST, FORM_PARAM_NAME_VALUE).build();
     private static final AwsProxyRequest REQUEST_MALFORMED_COOKIE = new AwsProxyRequestBuilder("/hello", "GET")
             .header(HttpHeaders.COOKIE, QUERY_STRING_NAME_VALUE).build();
+    private static final AwsProxyRequest REQUEST_MULTIPLE_FORM_AND_QUERY = new AwsProxyRequestBuilder("/hello", "POST")
+            .form(FORM_PARAM_NAME, FORM_PARAM_NAME_VALUE)
+            .queryString(FORM_PARAM_TEST, QUERY_STRING_NAME_VALUE).build();
 
     private static final AwsProxyRequest REQUEST_NULL_QUERY_STRING;
     static {
@@ -177,4 +181,25 @@ public void queryParameters_getParameterNames_notNull() {
         assertEquals(1, parameterNames.size());
         assertTrue(parameterNames.contains(FORM_PARAM_NAME));
     }
+
+    @Test
+    public void queryParameter_getParameterMap_avoidDuplicationOnMultipleCalls() {
+        HttpServletRequest request = new AwsProxyHttpServletRequest(REQUEST_MULTIPLE_FORM_AND_QUERY, null, null);
+
+        Map<String, String[]> params = request.getParameterMap();
+        assertNotNull(params);
+        assertEquals(2, params.size());
+        assertNotNull(params.get(FORM_PARAM_NAME));
+        assertEquals(1, params.get(FORM_PARAM_NAME).length);
+        assertNotNull(params.get(FORM_PARAM_TEST));
+        assertEquals(1, params.get(FORM_PARAM_TEST).length);
+
+        params = request.getParameterMap();
+        assertNotNull(params);
+        assertEquals(2, params.size());
+        assertNotNull(params.get(FORM_PARAM_NAME));
+        assertEquals(1, params.get(FORM_PARAM_NAME).length);
+        assertNotNull(params.get(FORM_PARAM_TEST));
+        assertEquals(1, params.get(FORM_PARAM_TEST).length);
+    }
 }