diff --git a/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java b/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java index 9908d89862..fa3ed112d4 100644 --- a/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java +++ b/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java @@ -1,5 +1,5 @@ /* - * Copyright 2002-2018 the original author or authors. + * Copyright 2002-2019 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -118,7 +118,11 @@ public class LinkedMultiValueMap implements MultiValueMap, Serializa @Override public Map toSingleValueMap() { LinkedHashMap singleValueMap = new LinkedHashMap<>(this.targetMap.size()); - this.targetMap.forEach((key, value) -> singleValueMap.put(key, value.get(0))); + this.targetMap.forEach((key, values) -> { + if (values != null && !values.isEmpty()) { + singleValueMap.put(key, values.get(0)); + } + }); return singleValueMap; } diff --git a/spring-core/src/test/java/org/springframework/util/LinkedMultiValueMapTests.java b/spring-core/src/test/java/org/springframework/util/LinkedMultiValueMapTests.java index 9ffb981984..b5639cc6e4 100644 --- a/spring-core/src/test/java/org/springframework/util/LinkedMultiValueMapTests.java +++ b/spring-core/src/test/java/org/springframework/util/LinkedMultiValueMapTests.java @@ -1,5 +1,5 @@ /* - * Copyright 2002-2017 the original author or authors. + * Copyright 2002-2019 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -29,10 +29,11 @@ import static org.junit.Assert.*; /** * @author Arjen Poutsma + * @author Juergen Hoeller */ public class LinkedMultiValueMapTests { - private final LinkedMultiValueMap map = new LinkedMultiValueMap(); + private final LinkedMultiValueMap map = new LinkedMultiValueMap<>(); @Test @@ -47,7 +48,15 @@ public class LinkedMultiValueMapTests { } @Test - public void addAll() throws Exception { + public void set() { + map.set("key", "value1"); + map.set("key", "value2"); + assertEquals(1, map.size()); + assertEquals(Collections.singletonList("value2"), map.get("key")); + } + + @Test + public void addAll() { map.add("key", "value1"); map.addAll("key", Arrays.asList("value2", "value3")); assertEquals(1, map.size()); @@ -58,6 +67,14 @@ public class LinkedMultiValueMapTests { assertEquals(expected, map.get("key")); } + @Test + public void addAllWithEmptyList() { + map.addAll("key", Collections.emptyList()); + assertEquals(1, map.size()); + assertEquals(Collections.emptyList(), map.get("key")); + assertNull(map.getFirst("key")); + } + @Test public void getFirst() { List values = new ArrayList<>(2); @@ -69,11 +86,29 @@ public class LinkedMultiValueMapTests { } @Test - public void set() { - map.set("key", "value1"); - map.set("key", "value2"); - assertEquals(1, map.size()); - assertEquals(Collections.singletonList("value2"), map.get("key")); + public void getFirstWithEmptyList() { + map.put("key", Collections.emptyList()); + assertNull(map.getFirst("key")); + assertNull(map.getFirst("other")); + } + + @Test + public void toSingleValueMap() { + List values = new ArrayList<>(2); + values.add("value1"); + values.add("value2"); + map.put("key", values); + Map svm = map.toSingleValueMap(); + assertEquals(1, svm.size()); + assertEquals("value1", svm.get("key")); + } + + @Test + public void toSingleValueMapWithEmptyList() { + map.put("key", Collections.emptyList()); + Map svm = map.toSingleValueMap(); + assertEquals(0, svm.size()); + assertNull(svm.get("key")); } @Test