JarCasting
JacksonUtils
a java tool to make working with Jackson Project more comfortable
Features
- Encapsulate all checked exceptions from Jackson with custom runtime exception;
- A centralized configuration of
ObjectMapper; - A central place of settings and all
ObjectMapperinstances; - Utility class to make most common operations much more comfortable to use;
- Ability to change
Zoneto saveZonedDateTimeindependently of original zone; InputStreamsupport for objects, lists and maps;- Lazy read support for list from
InputStream.
Gradle
compile 'ru.oleg-cherednik.utils:jackson-utils:2.12.0.4'
Maven
<dependency>
<groupId>ru.oleg-cherednik.utils</groupId>
<artifactId>jackson-utils</artifactId>
<version>2.12.0.4</version>
</dependency>
In the version, first 3 places are the version of Jackson that is used in this utils. The last section is the jackson-utils version. This number is unique.
Usage
To simplify usage of jackson-utils, there're following classes:
- JacksonUtils - utility class with set of method to use json transformation;
JacksonUtils class
Read json from String
String to a custom object type (but not a collection)
class Data {
int intVal;
String strVal;
}
String json = """
{
"intVal" : 666,
"strVal" : "omen"
}
""";
Data data = JacksonUtils.readValue(json, Data.class);
String to a list of custom object type
class Data {
int intVal;
String strVal;
}
String json = """
[
{
"intVal" : 555,
"strVal" : "victory"
},
{
"intVal" : 666,
"strVal" : "omen"
}
]
""";
List<Data> res = JacksonUtils.readList(json, Data.class);
String to a map of custom object type
Map with String keys and Map or primitive types as values
String json = """
{
"victory" : {
"intVal" : 555,
"strVal" : "victory"
},
"omen" : {
"intVal" : 666,
"strVal" : "omen"
}
}
""";
Map<String, ?> map = JacksonUtils.readMap(json);
Note: map values have either primitive type or Map or List.
String to a map with String keys and given type as value
class Data {
int intVal;
String strVal;
}
String json = """
{
"victory" : {
"intVal" : 555,
"strVal" : "victory"
},
"omen" : {
"intVal" : 666,
"strVal" : "omen"
}
}
""";
Map<String, Data> map = JacksonUtils.readMap(json, Data.class);
String to a map with Integer keys and given type as value
class Data {
int intVal;
String strVal;
}
String json = """
{
"1" : {
"intVal" : 555,
"strVal" : "victory"
},
"2" : {
"intVal" : 666,
"strVal" : "omen"
}
}
""";
Map<Integer, Data> map = JacksonUtils.readMap(json, Integer.class, Data.class);
Read json from InputStream
InputStream to a custom object type (but not a collection)
class Data {
int intVal;
String strVal;
}
{
"intVal" : 666,
"strVal" : "omen"
}
try (InputStream in = ...) {
Data data = JacksonUtils.readValue(in, Data.class);
}
InputStream to a list of custom object type
Read eager
class Data {
int intVal;
String strVal;
}
[
{
"intVal" : 555,
"strVal" : "victory"
},
{
"intVal" : 666,
"strVal" : "omen"
}
]
try (InputStream in = ...) {
List<Data> res = JacksonUtils.readList(in, Data.class);
}
Read lazy
class Data {
int intVal;
String strVal;
}
[
{
"intVal" : 555,
"strVal" : "victory"
},
{
"intVal" : 666,
"strVal" : "omen"
}
]
try (InputStream in = ...) {
Iterator<Data> it = JacksonUtils.readListLazy(in, Data.class);
while (it.hasNext()) {
Data data = it.next();
}
}
InputStream to a map of custom object type
InputStream to a map with String keys and Map or primitive types as values
{
"victory" : {
"intVal" : 555,
"strVal" : "victory"
},
"omen" : {
"intVal" : 666,
"strVal" : "omen"
}
}
try (InputStream in = ...) {
Map<String, ?> map = JacksonUtils.readMap(in);
}
Note: map values have either primitive type or Map or List.
InputStream to a map with String keys and given type as value
class Data {
int intVal;
String strVal;
}
{
"victory" : {
"intVal" : 555,
"strVal" : "victory"
},
"omen" : {
"intVal" : 666,
"strVal" : "omen"
}
}
try (InputStream in = ...) {
Map<String, ?> map = JacksonUtils.readMap(in, Data.class);
}
Map with Integer keys and given type as value
class Data {
int intVal;
String strVal;
}
{
"1" : {
"intVal" : 555,
"strVal" : "victory"
},
"2" : {
"intVal" : 666,
"strVal" : "omen"
}
}
try (InputStream in = ...) {
Map<Integer, Data> map = JacksonUtils.readMap(in, Integer.class, Data.class);
}