How to fluently build JSON in Java

Question

I m thinking of something like   String json   new JsonBuilder      add  key1    value1      add  key2    value2      add  key3   new JsonBuilder        add  innerKey1    value3       toJson      Which Java JSON library is best for this kind of fluent building   Update  I wrapped GSON and got almost the desired result     with one hitch

User · Answer

Underscore-java library has json builder  String json   U objectBuilder      add  quot key1 quot    quot value1 quot      add  quot key2 quot    quot value2 quot      add  quot key3 quot   U objectBuilder        add  quot innerKey1 quot    quot value3 quot       toJson

User · Answer

I got here looking for a nice way to write rest endpoint tests with a fluent json builder  In my case I used JSONObject to construct a specialized builder  It need a bit of instrumentation  but the usage is really nice  import lombok SneakyThrows  import org json JSONObject   public class MemberJson extends JSONObject         SneakyThrows     public static MemberJson builder             return new MemberJson                SneakyThrows     public MemberJson name String name            put  quot name quot   name           return this            MemberJson builder   name  quot Member quot   toString

User · Answer

It sounds like you probably want to get ahold of json-lib   http   json-lib sourceforge net   Douglas Crockford is the guy who invented JSON  his Java library is here   http   www json org java   It sounds like the folks at json-lib picked up where Crockford left off   Both fully support JSON  both use  compatible  as far as I can tell  JSONObject   JSONArray and JSONFunction constructs    Hope that helps

User · Answer

The reference implementation includes a fluent interface  Check out JSONWriter and its toString-implementing subclass JSONStringer

User · Answer

See the Java EE 7 Json specification  This is the right way   String json   Json createObjectBuilder                add  key1    value1                add  key2    value2                build                toString

User · Answer

String json   new JsonBuilder new GsonAdapter       object  key1    value1      object  key2    value2      object  key3        object  innerKey1    value3        build   toString      If you think the above solution is elegant  then please try out my JsonBuilder lib  It was created to allow one way of building json structures for many types of Json libraries  Current implementations include Gson  Jackson and MongoDB   For ie  Jackson just swap   String json   new JsonBuilder new JacksonAdapter       I ll happily add others on request  it s also quite easy to implement one by oneself

User · Answer

it s much easier than you think to write your own  just use an interface for JsonElementInterface with a method string toJson    and an abstract class AbstractJsonElement implementing that interface   then all you have to do is have a class for JSONProperty that implements the interface  and JSONValue any token   JSONArray          and JSONObject         that extend the abstract class  JSONObject has a list of JSONProperty s JSONArray has a list of AbstractJsonElement s  your add function in each should take a vararg list of that type  and return this  now if you don t like something you can just tweak it  the benifit of the inteface and the abstract class is that JSONArray can t accept properties  but JSONProperty can accept objects or arrays

User · Answer

You can use one of Java template engines  I love this method because you are separating your logic from the view  Java 8    lt dependency gt     lt groupId gt com github spullara mustache java lt  groupId gt     lt artifactId gt compiler lt  artifactId gt     lt version gt 0 9 6 lt  version gt   lt  dependency gt   Java 6 7   lt dependency gt     lt groupId gt com github spullara mustache java lt  groupId gt     lt artifactId gt compiler lt  artifactId gt     lt version gt 0 8 18 lt  version gt   lt  dependency gt   Example template file     items   Name    name   Price    price        features     Feature    description        features      items    Might be powered by some backing code  public class Context     List lt Item gt  items         return Arrays asList        new Item  quot Item 1 quot    quot  19 99 quot   Arrays asList new Feature  quot New  quot    new Feature  quot Awesome  quot            new Item  quot Item 2 quot    quot  29 99 quot   Arrays asList new Feature  quot Old  quot    new Feature  quot Ugly  quot                   static class Item       Item String name  String price  List lt Feature gt  features          this name   name        this price   price        this features   features            String name  price      List lt Feature gt  features         static class Feature       Feature String description           this description   description            String description         And would result in  Name  Item 1 Price   19 99   Feature  New    Feature  Awesome  Name  Item 2 Price   29 99   Feature  Old    Feature  Ugly    mustache  https   github com spullara mustache java But there is also Jinja  https   github com HubSpot jinjava And carrot  https   github com codeka carrot

User · Answer

I recently created a library for creating Gson objects fluently   http   jglue org fluent-json   It works like this     JsonObject jsonObject   JsonBuilderFactory buildObject     Create a new builder for an object    addNull  nullKey                                1  Add a null to the object     add  stringKey    Hello                         2  Add a string to the object    add  stringNullKey    String  null              3  Add a null string to the object     add  numberKey   2                              4  Add a number to the object    add  numberNullKey    Float  null               5  Add a null number to the object     add  booleanKey   true                          6  Add a boolean to the object    add  booleanNullKey    Boolean  null            7  Add a null boolean to the object     add  characterKey    c                          8  Add a character to the object    add  characterNullKey    Character  null        9  Add a null character to the object     addObject  objKey                               10  Add a nested object      add  nestedPropertyKey   4                    11  Add a nested property to the nested object      end                                           12  End nested object and return to the parent builder     addArray  arrayKey                              13  Add an array to the object      addObject                                     14  Add a nested object to the array        end                                         15  End the nested object      add  arrayElement                             16  Add a string to the array      end                                           17  End the array       getJson                                       Get the JsonObject  String json   jsonObject toString      And through the magic of generics it generates compile errors if you try to add an element to an array with a property key or an element to an object without a property name   JsonObject jsonArray   JsonBuilderFactory buildArray   addObject   end   add  foo    bar   getJson      Error  tried to add a string with property key to array  JsonObject jsonObject   JsonBuilderFactory buildObject   addArray   end   add  foo   getJson      Error  tried to add a string without property key to an object  JsonArray jsonArray   JsonBuilderFactory buildObject   addArray  foo   getJson      Error  tried to assign an object to an array  JsonObject jsonObject   JsonBuilderFactory buildArray   addObject   getJson      Error  tried to assign an object to an array    Lastly there is mapping support in the API which allows you to map your domain objects to JSON  The goal being when Java8 is released you ll be able to do something like this   Collection lt User gt  users        JsonArray jsonArray   JsonBuilderFactory buildArray users    u- gt  buildObject                                                                     add  userName   u getName                                                                      add  ageInYears   u getAge                                                                         getJson

User · Answer

If you are using Jackson do a lot of JsonNode building in code  you may be interesting in the following set of utilities  The benefit of using them is that they support a more natural chaining style that better shows the structure of the JSON under construction   Here is an example usage   import static JsonNodeBuilders array  import static JsonNodeBuilders object        val request   object  x    1   with  y   array object  z    2     end      Which is equivalent to the following JSON     x   1    y      z    2       Here are the classes   import static lombok AccessLevel PRIVATE   import com fasterxml jackson databind JsonNode  import com fasterxml jackson databind node ArrayNode  import com fasterxml jackson databind node JsonNodeFactory  import com fasterxml jackson databind node ObjectNode   import lombok NoArgsConstructor  import lombok NonNull  import lombok RequiredArgsConstructor  import lombok val          Convenience   link JsonNode  builder       NoArgsConstructor access   PRIVATE  public final class JsonNodeBuilders               Factory methods for an   link ObjectNode  builder           public static ObjectNodeBuilder object         return object JsonNodeFactory instance          public static ObjectNodeBuilder object  NonNull String k1  boolean v1        return object   with k1  v1          public static ObjectNodeBuilder object  NonNull String k1  int v1        return object   with k1  v1          public static ObjectNodeBuilder object  NonNull String k1  float v1        return object   with k1  v1          public static ObjectNodeBuilder object  NonNull String k1  String v1        return object   with k1  v1          public static ObjectNodeBuilder object  NonNull String k1  String v1   NonNull String k2  String v2        return object k1  v1  with k2  v2          public static ObjectNodeBuilder object  NonNull String k1  String v1   NonNull String k2  String v2         NonNull String k3  String v3        return object k1  v1  k2  v2  with k3  v3          public static ObjectNodeBuilder object  NonNull String k1  JsonNodeBuilder lt   gt  builder        return object   with k1  builder          public static ObjectNodeBuilder object JsonNodeFactory factory        return new ObjectNodeBuilder factory                   Factory methods for an   link ArrayNode  builder           public static ArrayNodeBuilder array         return array JsonNodeFactory instance          public static ArrayNodeBuilder array  NonNull boolean    values        return array   with values          public static ArrayNodeBuilder array  NonNull int    values        return array   with values          public static ArrayNodeBuilder array  NonNull String    values        return array   with values          public static ArrayNodeBuilder array  NonNull JsonNodeBuilder lt   gt     builders        return array   with builders          public static ArrayNodeBuilder array JsonNodeFactory factory        return new ArrayNodeBuilder factory          public interface JsonNodeBuilder lt T extends JsonNode gt                    Construct and return the   link JsonNode  instance              T end             RequiredArgsConstructor   private static abstract class AbstractNodeBuilder lt T extends JsonNode gt  implements JsonNodeBuilder lt T gt                    The source of values               NonNull     protected final JsonNodeFactory factory                  The value under construction               NonNull     protected final T node                  Returns a valid JSON string  so long as   code POJONode s not used               Override     public String toString           return node toString                  public final static class ObjectNodeBuilder extends AbstractNodeBuilder lt ObjectNode gt         private ObjectNodeBuilder JsonNodeFactory factory          super factory  factory objectNode                public ObjectNodeBuilder withNull  NonNull String field          return with field  factory nullNode                public ObjectNodeBuilder with  NonNull String field  int value          return with field  factory numberNode value               public ObjectNodeBuilder with  NonNull String field  float value          return with field  factory numberNode value               public ObjectNodeBuilder with  NonNull String field  boolean value          return with field  factory booleanNode value               public ObjectNodeBuilder with  NonNull String field  String value          return with field  factory textNode value               public ObjectNodeBuilder with  NonNull String field  JsonNode value          node set field  value         return this             public ObjectNodeBuilder with  NonNull String field   NonNull JsonNodeBuilder lt   gt  builder          return with field  builder end                public ObjectNodeBuilder withPOJO  NonNull String field   NonNull Object pojo          return with field  factory pojoNode pojo                Override     public ObjectNode end           return node                public final static class ArrayNodeBuilder extends AbstractNodeBuilder lt ArrayNode gt         private ArrayNodeBuilder JsonNodeFactory factory          super factory  factory arrayNode                public ArrayNodeBuilder with boolean value          node add value         return this             public ArrayNodeBuilder with  NonNull boolean    values          for  val value   values          with value         return this             public ArrayNodeBuilder with int value          node add value         return this             public ArrayNodeBuilder with  NonNull int    values          for  val value   values          with value         return this             public ArrayNodeBuilder with float value          node add value         return this             public ArrayNodeBuilder with String value          node add value         return this             public ArrayNodeBuilder with  NonNull String    values          for  val value   values          with value         return this             public ArrayNodeBuilder with  NonNull Iterable lt String gt  values          for  val value   values          with value         return this             public ArrayNodeBuilder with JsonNode value          node add value         return this             public ArrayNodeBuilder with  NonNull JsonNode    values          for  val value   values          with value         return this             public ArrayNodeBuilder with JsonNodeBuilder lt   gt  value          return with value end                public ArrayNodeBuilder with  NonNull JsonNodeBuilder lt   gt     builders          for  val builder   builders          with builder         return this              Override     public ArrayNode end           return node                  Note that the implementation uses Lombok  but you can easily desugar it to fill in the Java boilerplate

User · Answer

I am using the org json library and found it to be nice and friendly   Example   String jsonString   new JSONObject                      put  JSON1    Hello World                       put  JSON2    Hello my World                       put  JSON3   new JSONObject   put  key1    value1                       toString     System out println jsonString     OUTPUT     JSON2   Hello my World    JSON3    key1   value1    JSON1   Hello World

[java] How to fluently build JSON in Java?

Examples related to java

Examples related to json