BAEL-6818 Add examples for checking if a value exists in a JSON array

json-modules/json-arrays/pom.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>org.baeldung</groupId>
+    <artifactId>json-arrays</artifactId>
+    <name>json-arrays</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>json-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+            <version>${json.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.json.bind</groupId>
+            <artifactId>javax.json.bind-api</artifactId>
+            <version>${jsonb-api.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <jsonb-api.version>1.0</jsonb-api.version>
+        <json.version>20230227</json.version>
+        <gson.version>2.8.5</gson.version>
+        <javax.version>1.1.2</javax.version>
+        <json-unit-assertj.version>2.28.0</json-unit-assertj.version>
+    </properties>
+
+</project>

json-modules/json-arrays/src/test/java/com.baeldung.checkforkey/CheckForKeyUnitTest.java

@@ -0,0 +1,45 @@
+package com.baeldung.checkforkey;
+
+import java.util.Objects;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.gson.Gson;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+
+public class CheckForKeyUnitTest {
+
+    private final String exampleJson = "[{\"colour\":\"red\"},{\"colour\":\"blue\"},{\"colour\":\"green\"}]";
+
+    @Test
+    public void givenJsonArray_whenUsingJackson_thenDetectKeyInArray() throws JsonProcessingException {
+        ObjectMapper objectMapper = new ObjectMapper();
+        JsonNode tree = objectMapper.readTree(exampleJson);
+
+        Stream<JsonNode> s = StreamSupport.stream(tree.spliterator(), false);
+        boolean result = s.map(entry -> entry.get("colour"))
+          .filter(Objects::nonNull)
+          .anyMatch(colour -> "green".equals(colour.asText()));
+        assert (result);
+    }
+
+    @Test
+    public void givenJsonArray_whenUsingGson_thenDetectKeyInArray() {
+        Gson gson = new Gson();
+        JsonArray parsed = gson.fromJson(exampleJson, JsonArray.class);
+
+        Stream<JsonElement> s = StreamSupport.stream(parsed.spliterator(), false);
+        boolean result = s.map(entry -> entry.getAsJsonObject()
+          .get("colour"))
+          .filter(Objects::nonNull)
+          .anyMatch(colour -> "green".equals(colour.getAsString()));
+        assert (result);
+    }
+
+}

json-modules/pom.xml

@@ -19,6 +19,7 @@
         <module>json-path</module>
         <module>gson</module>
         <module>gson-2</module>
+        <module>json-arrays</module>
     </modules>
 
     <build>