Package org.springframework.boot.json
Interface JsonWriter<T>
- Type Parameters:
T
- the type being written
- Functional Interface:
- This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
Interface that can be used to write JSON output. Typically used to generate JSON when a
dependency on a fully marshalling library (such as Jackson or Gson) cannot be assumed.
For standard Java types, the standard()
factory method may be used to obtain
an instance of this interface. It supports String
, Number
and
Boolean
as well as Collection
, Array
, Map
and
JsonWriter.WritableJson
types. Typical usage would be:
JsonWriter<Map<String,Object>> writer = JsonWriter.standard(); writer.write(Map.of("Hello", "World!"), out);
More complex mappings can be created using the of(Consumer)
method with a
callback to configure the JSON members
that should be written. Typical
usage would be:
JsonWriter<Person> writer = JsonWriter.of((members) -> { members.add("first", Person::firstName); members.add("last", Person::lastName); members.add("dob", Person::dateOfBirth) .whenNotNull() .as(DateTimeFormatter.ISO_DATE::format); }); writer.write(person, out);
The writeToString(Object)
method can be used if you want to write the JSON
directly to a String
. To write to other types of output, the
write(Object)
method may be used to obtain a JsonWriter.WritableJson
instance.
- Since:
- 3.4.0
- Author:
- Phillip Webb, Moritz Halbritter
-
Nested Class Summary
Nested ClassesModifier and TypeInterfaceDescriptionstatic final class
A member that contributes JSON.static final class
Callback used to configure JSON members.static interface
Interface that can be used to extract name/value pairs from an element.static interface
JSON content that can be written out. -
Method Summary
Modifier and TypeMethodDescriptionstatic <T> JsonWriter<T>
of
(Consumer<JsonWriter.Members<T>> members) Factory method to return aJsonWriter
with specificmember mapping
.static <T> JsonWriter<T>
standard()
Factory method to return aJsonWriter
for standard Java types.default JsonWriter<T>
Return a newJsonWriter
instance that appends a new line after the JSON has been written.default JsonWriter<T>
withSuffix
(String suffix) Return a newJsonWriter
instance that appends the given suffix after the JSON has been written.default JsonWriter.WritableJson
Provide aJsonWriter.WritableJson
implementation that may be used to write the given instance to various outputs.void
write
(T instance, Appendable out) Write the given instance to the providedAppendable
.default String
writeToString
(T instance) Write the given instance to a JSON string.
-
Method Details
-
write
Write the given instance to the providedAppendable
.- Parameters:
instance
- the instance to write (may benull
out
- the output that should receive the JSON- Throws:
IOException
- on IO error
-
writeToString
Write the given instance to a JSON string.- Parameters:
instance
- the instance to write (may benull
)- Returns:
- the JSON string
-
write
Provide aJsonWriter.WritableJson
implementation that may be used to write the given instance to various outputs.- Parameters:
instance
- the instance to write (may benull
)- Returns:
- a
JsonWriter.WritableJson
instance that may be used to write the JSON
-
withNewLineAtEnd
Return a newJsonWriter
instance that appends a new line after the JSON has been written.- Returns:
- a new
JsonWriter
instance that appends a new line after the JSON
-
withSuffix
Return a newJsonWriter
instance that appends the given suffix after the JSON has been written.- Parameters:
suffix
- the suffix to write, if any- Returns:
- a new
JsonWriter
instance that appends a suffixafter the JSON
-
standard
Factory method to return aJsonWriter
for standard Java types. Seeclass-level javadoc
for details.- Type Parameters:
T
- the type to write- Returns:
- a
JsonWriter
instance
-
of
Factory method to return aJsonWriter
with specificmember mapping
. Seeclass-level javadoc
andJsonWriter.Members
for details.- Type Parameters:
T
- the type to write- Parameters:
members
- a consumer, which should configure the members- Returns:
- a
JsonWriter
instance - See Also:
-