Code sample for BAEL-2085

gson/src/main/java/org/baeldung/gson/entities/User.java

@@ -0,0 +1,19 @@
+package org.baeldung.gson.entities;
+
+public class User {
+
+	private int id;
+	private String name;
+	private transient String nationality;
+
+	public User(int id, String name, String nationality) {
+		this.id = id;
+		this.name = name;
+		this.nationality = nationality;
+	}
+
+	public User(int id, String name) {
+		this(id, name, null);
+	}
+
+}

gson/src/test/java/org/baeldung/gson/serialization/test/JsonFileUnitTest.java

@@ -0,0 +1,43 @@
+package org.baeldung.gson.serialization.test;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import org.baeldung.gson.entities.User;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+@RunWith(Parameterized.class)
+public class JsonFileUnitTest {
+
+	@Parameter
+	public Object object;
+
+	@Parameters
+	public static Object[] data() {
+		return new Object[] { 123.45, new User(1, "Tom", "American") };
+	}
+
+	@Test
+	public void givenProperData_whenStoredInFile_shouldSaveJsonSuccessfully() {
+		String filePath = "target/output.json";
+		try (Writer writer = new FileWriter(filePath)) {
+			Gson gson = new GsonBuilder().setPrettyPrinting().create();
+			gson.toJson(object, writer);
+			Assert.assertTrue(Files.exists(Paths.get(filePath)));
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+
+}