BAEL-7944 - Sort JSON Object in Java (eugenp#17091)

* BAEL-7864 - How to convert org.w3c.dom.Document to String in Java

* BAEL-7944 - Sort JSON Object in Java

---------

Co-authored-by: jcook02 <[email protected]>

json-modules/json-operations/README.md

@@ -0,0 +1,2 @@
+## Relevant Articles
+

json-modules/json-operations/pom.xml

@@ -0,0 +1,33 @@
+<?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-operations</artifactId>
+    <name>json-operations</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>json-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <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>
+    </dependencies>
+
+    <properties>
+        <gson.version>2.11.0</gson.version>
+    </properties>
+
+</project>

json-modules/json-operations/src/main/java/com/baeldung/sorting/SolarEvent.java

@@ -0,0 +1,103 @@
+package com.baeldung.sorting;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+class SolarEvent {
+
+    @JsonProperty("event_name")
+    private String eventName;
+    @JsonProperty("date")
+    private String date;
+    @JsonProperty("coordinates")
+    private Coordinates coordinates;
+    @JsonProperty("type")
+    private String type;
+    @JsonProperty("class")
+    private String eventClass;
+    @JsonProperty("size")
+    private String size;
+    @JsonProperty("speed_km_per_s")
+    private int speedKmPerS;
+
+    public String getEventName() {
+        return eventName;
+    }
+
+    public void setEventName(String eventName) {
+        this.eventName = eventName;
+    }
+
+    public String getDate() {
+        return date;
+    }
+
+    public void setDate(String date) {
+        this.date = date;
+    }
+
+    public Coordinates getCoordinates() {
+        return coordinates;
+    }
+
+    public void setCoordinates(Coordinates coordinates) {
+        this.coordinates = coordinates;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getEventClass() {
+        return eventClass;
+    }
+
+    public void setEventClass(String eventClass) {
+        this.eventClass = eventClass;
+    }
+
+    public String getSize() {
+        return size;
+    }
+
+    public void setSize(String size) {
+        this.size = size;
+    }
+
+    public int getSpeedKmPerS() {
+        return speedKmPerS;
+    }
+
+    public void setSpeedKmPerS(int speedKmPerS) {
+        this.speedKmPerS = speedKmPerS;
+    }
+}
+
+class Coordinates {
+
+    @JsonProperty("latitude")
+    private double latitude;
+
+    @JsonProperty("longitude")
+    private double longitude;
+
+    public double getLatitude() {
+        return latitude;
+    }
+
+    public void setLatitude(double latitude) {
+        this.latitude = latitude;
+    }
+
+    public double getLongitude() {
+        return longitude;
+    }
+
+    public void setLongitude(double longitude) {
+        this.longitude = longitude;
+    }
+
+}

json-modules/json-operations/src/main/java/com/baeldung/sorting/SolarEventContainer.java

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+package com.baeldung.sorting;
+
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class SolarEventContainer {
+
+    @JsonProperty("solar_events")
+    private List<SolarEvent> solarEvents;
+
+    // Getters and setters
+    public List<SolarEvent> getSolarEvents() {
+        return solarEvents;
+    }
+
+    public void setSolarEvents(List<SolarEvent> solarEvents) {
+        this.solarEvents = solarEvents;
+    }
+}

json-modules/json-operations/src/test/java/com/baeldung/sorting/JsonObjectSortingUnitTest.java

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+package com.baeldung.sorting;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParser;
+import com.google.gson.stream.JsonReader;
+
+class JsonObjectSortingUnitTest {
+
+    @Test
+    void givenJsonObject_whenUsingJackson_thenSortedBySpeedCorrectly() throws IOException {
+        ObjectMapper objectMapper = new ObjectMapper();
+        SolarEventContainer container = objectMapper.readValue(
+            new File("src/test/resources/solar_events.json"), SolarEventContainer.class);
+
+        List<SolarEvent> events = container.getSolarEvents();
+        Collections.sort(events, Comparator.comparingInt(event -> event.getSpeedKmPerS()));
+
+        assertEquals(100, events.get(0)
+            .getSpeedKmPerS());
+        assertEquals(500, events.get(1)
+            .getSpeedKmPerS());
+        assertEquals(1000, events.get(2)
+            .getSpeedKmPerS());
+        assertEquals(1500, events.get(3)
+            .getSpeedKmPerS());
+    }
+
+    @Test
+    public void givenJsonObject_whenUsingGson_thenSortedBySizeCorrectly() throws FileNotFoundException {
+        JsonReader reader = new JsonReader(new FileReader("src/test/resources/solar_events.json"));
+        JsonElement element = JsonParser.parseReader(reader);
+        JsonArray events = element.getAsJsonObject().getAsJsonArray("solar_events");
+        List<JsonElement> list = events.asList();
+
+        Collections.sort(list, (a, b) -> {
+            double latA = a.getAsJsonObject()
+                .getAsJsonObject("coordinates")
+                .get("latitude")
+                .getAsDouble();
+            double latB = b.getAsJsonObject()
+                .getAsJsonObject("coordinates")
+                .get("latitude")
+                .getAsDouble();
+            return Double.compare(latA, latB);
+        });
+
+        assertEquals(-5, getJsonAttributeAsInt(list.get(0)));
+        assertEquals(0, getJsonAttributeAsInt(list.get(1)));
+        assertEquals(15, getJsonAttributeAsInt(list.get(2)));
+        assertEquals(37, getJsonAttributeAsInt(list.get(3)));
+    }
+
+    private int getJsonAttributeAsInt(JsonElement element) {
+        return element.getAsJsonObject()
+            .getAsJsonObject("coordinates")
+            .get("latitude")
+            .getAsInt();
+    }
+
+}

json-modules/json-operations/src/test/resources/solar_events.json

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+{
+  "solar_events": [
+    {
+      "event_name": "Solar Eclipse",
+      "date": "2024-04-08",
+      "coordinates": {
+        "latitude": 37.7749,
+        "longitude": -122.4194
+      },
+      "size": "Large",
+      "speed_km_per_s": 1000
+    },
+    {
+      "event_name": "Solar Flare",
+      "date": "2023-10-28",
+      "coordinates": {
+        "latitude": 0,
+        "longitude": 0
+      },
+      "size": "Small",
+      "speed_km_per_s": 100
+    },
+    {
+      "event_name": "Sunspot",
+      "date": "2023-11-15",
+      "coordinates": {
+        "latitude": 15,
+        "longitude": -75
+      },
+      "size": "Large",
+      "speed_km_per_s": 1500
+    },
+    {
+      "event_name": "Coronal Mass Ejection",
+      "date": "2024-01-10",
+      "coordinates": {
+        "latitude": -5,
+        "longitude": 80
+      },
+      "size": "Medium",
+      "speed_km_per_s": 500
+    }
+  ]
+}

json-modules/pom.xml

@@ -18,6 +18,7 @@
         <module>json-2</module>
         <module>json-arrays</module>
         <module>json-conversion</module>
+        <module>json-operations</module>
         <module>json-path</module>
         <module>gson</module>
         <module>gson-2</module>
@@ -38,4 +39,4 @@
         <json.version>20240303</json.version>
     </properties>
 
-</project>
+</project>