Examples for Moshi Json (#8753)

* Examples for Moshi Json

* Renamed Moshi tests to BDD style

* Updated some indents

* Minor code tweak to prefer ternary over if/else

libraries-3/pom.xml

@@ -73,6 +73,16 @@
             <version>${cache2k.version}</version>
             <type>pom</type>
         </dependency>
+        <dependency>
+            <groupId>com.squareup.moshi</groupId>
+            <artifactId>moshi</artifactId>
+            <version>${moshi.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.moshi</groupId>
+            <artifactId>moshi-adapters</artifactId>
+            <version>${moshi.version}</version>
+        </dependency>
         
         <dependency>
             <groupId>com.jcabi</groupId>
@@ -135,7 +145,7 @@
         <cactoos.version>0.43</cactoos.version>
         <airline.version>2.7.2</airline.version>
         <cache2k.version>1.2.3.Final</cache2k.version>
-        
+        <moshi.version>1.9.2</moshi.version>
         <jcabi-aspects.version>0.22.6</jcabi-aspects.version>
         <aspectjrt.version>1.9.2</aspectjrt.version>
         <jcabi-maven-plugin.version>0.14.1</jcabi-maven-plugin.version>

libraries-3/src/test/java/com/baeldung/moshi/AlternativeAdapterUnitTest.java

@@ -0,0 +1,105 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.time.Instant;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.JsonQualifier;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class AlternativeAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenAlternativeAdapterUsed() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new EpochMillisAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = jsonAdapter.toJson(new Post("Introduction to Moshi Json", "Baeldung", Instant.now()));
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenAlternativeAdapterUsed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new EpochMillisAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung\",\"posted\":1582095269204,\"title\":\"Introduction to Moshi Json\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+
+    }
+
+    public static class Post {
+        String title;
+        String author;
+        @EpochMillis Instant posted;
+
+        public Post() {
+        }
+
+        public Post(String title, String author, Instant posted) {
+            this.title = title;
+            this.author = author;
+            this.posted = posted;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public Instant getPosted() {
+            return posted;
+        }
+
+        public void setPosted(Instant posted) {
+            this.posted = posted;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("posted", posted)
+                .toString();
+        }
+    }
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})
+    @JsonQualifier
+    public @interface EpochMillis {
+    }
+
+    public static class EpochMillisAdapter {
+        @ToJson
+        public Long toJson(@EpochMillis Instant input) {
+            return input.toEpochMilli();
+        }
+        @FromJson
+        @EpochMillis
+        public Instant fromJson(Long input) {
+            return Instant.ofEpochMilli(input);
+        }
+
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/ArrayUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.Arrays;
+import java.util.List;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.Types;
+import org.junit.Test;
+
+public class ArrayUnitTest {
+    @Test
+    public void whenSerializingList_thenJsonArrayProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        Type type = Types.newParameterizedType(List.class, String.class);
+        JsonAdapter<List<String>> jsonAdapter = moshi.adapter(type);
+
+        String json = jsonAdapter.toJson(Arrays.asList("One", "Two", "Three"));
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializingJsonArray_thenListProduced() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        Type type = Types.newParameterizedType(List.class, String.class);
+        JsonAdapter<List<String>> jsonAdapter = moshi.adapter(type);
+
+        String json = "[\"One\",\"Two\",\"Three\"]";
+        List<String> result = jsonAdapter.fromJson(json);
+        System.out.println(result);
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/ComplexAdapterUnitTest.java

@@ -0,0 +1,94 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.junit.Test;
+
+public class ComplexAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenCorrectJsonProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new JsonDateTimeAdapter())
+          .build();
+        JsonAdapter<ZonedDateTime> jsonAdapter = moshi.adapter(ZonedDateTime.class);
+
+        String json = jsonAdapter.toJson(ZonedDateTime.now());
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenCorrectJsonConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new JsonDateTimeAdapter())
+          .build();
+        JsonAdapter<ZonedDateTime> jsonAdapter = moshi.adapter(ZonedDateTime.class);
+
+        String json = "{\"date\":\"2020-02-17\",\"time\":\"07:53:27.064\",\"timezone\":\"Europe/London\"}";
+        ZonedDateTime now = jsonAdapter.fromJson(json);
+        System.out.println(now);
+
+    }
+
+    public static class JsonDateTimeAdapter {
+        @ToJson
+        public JsonDateTime toJson(ZonedDateTime input) {
+            String date = input.toLocalDate().toString();
+            String time = input.toLocalTime().toString();
+            String timezone = input.getZone().toString();
+            return new JsonDateTime(date, time, timezone);
+        }
+        @FromJson
+        public ZonedDateTime fromJson(JsonDateTime input) {
+            LocalDate date = LocalDate.parse(input.getDate());
+            LocalTime time = LocalTime.parse(input.getTime());
+            ZoneId timezone = ZoneId.of(input.getTimezone());
+            return ZonedDateTime.of(date, time, timezone);
+        }
+    }
+    public static class JsonDateTime {
+        private String date;
+        private String time;
+        private String timezone;
+
+        public JsonDateTime() {
+        }
+
+        public JsonDateTime(String date, String time, String timezone) {
+            this.date = date;
+            this.time = time;
+            this.timezone = timezone;
+        }
+
+        public String getDate() {
+            return date;
+        }
+
+        public void setDate(String date) {
+            this.date = date;
+        }
+
+        public String getTime() {
+            return time;
+        }
+
+        public void setTime(String time) {
+            this.time = time;
+        }
+
+        public String getTimezone() {
+            return timezone;
+        }
+
+        public void setTimezone(String timezone) {
+            this.timezone = timezone;
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/DefaultUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.time.Instant;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class DefaultUnitTest {
+
+    @Test
+    public void whenDeserializing_thenFieldsGetDefaultValues() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        private String author;
+        private String posted;
+
+        public Post() {
+            posted = Instant.now().toString();
+        }
+
+        public Post(String title, String author, String posted) {
+            this.title = title;
+            this.author = author;
+            this.posted = posted;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public String getPosted() {
+            return posted;
+        }
+
+        public void setPosted(String posted) {
+            this.posted = posted;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("posted", posted)
+                .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/PrimitiveUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class PrimitiveUnitTest {
+    @Test
+    public void whenSerializing_thenCorrectJsonProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung", "This is my post");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenCorrectJsonConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung\",\"text\":\"This is my post\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+
+    public static class Post {
+        private String title;
+        private String author;
+        private String text;
+
+        public Post() {
+        }
+
+        public Post(String title, String author, String text) {
+            this.title = title;
+            this.author = author;
+            this.text = text;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("text", text)
+                .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/RenameUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.Json;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.jupiter.api.Test;
+
+public class RenameUnitTest {
+
+    @Test
+    public void whenSerializing_thenFieldsGetRenamed() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenSerializing_thenRenamedFieldsGetConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"authored_by\":\"Baeldung\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        @Json(name = "authored_by")
+        private String author;
+
+        public Post() {
+        }
+
+        public Post(String title, String author) {
+            this.title = title;
+            this.author = author;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/SimpleAdapterUnitTest.java

@@ -0,0 +1,129 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class SimpleAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenAdapterUsed() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new AuthorAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", new Author("Baeldung", "baeldung@example.com"), "This is my post");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenAdapterUsed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new AuthorAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung <baeldung@example.com>\",\"text\":\"This is my post\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class AuthorAdapter {
+        private Pattern pattern = Pattern.compile("^(.*) <(.*)>$");
+        @ToJson
+        public String toJson(Author author) {
+            return author.name + " <" + author.email + ">";
+        }
+
+        @FromJson
+        public Author fromJson(String author) {
+            Matcher matcher = pattern.matcher(author);
+            return matcher.find() ? new Author(matcher.group(1), matcher.group(2)) : null;
+        }
+    }
+
+    public static class Author {
+        private String name;
+        private String email;
+
+        public Author() {
+        }
+
+        public Author(String name, String email) {
+            this.name = name;
+            this.email = email;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public String getEmail() {
+            return email;
+        }
+
+        public void setEmail(String email) {
+            this.email = email;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("name", name).append("email", email).toString();
+        }
+    }
+    public static class Post {
+        private String title;
+        private Author author;
+        private String text;
+
+        public Post() {
+        }
+
+        public Post(String title, Author author, String text) {
+            this.title = title;
+            this.author = author;
+            this.text = text;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public Author getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(Author author) {
+            this.author = author;
+        }
+
+        public String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("text", text)
+              .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/TransientUnitTest.java

@@ -0,0 +1,66 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.jupiter.api.Test;
+
+public class TransientUnitTest {
+
+    @Test
+    public void whenSerializing_thenTransientFieldIgnored() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenTransientFieldIgnored() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"authored_by\":\"Baeldung\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        private transient String author;
+
+        public Post() {
+        }
+
+        public Post(String title, String author) {
+            this.title = title;
+            this.author = author;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).toString();
+        }
+    }
+}