jackson nested object map implementation
1
Is there any way to tell jackson library whish Map implementation to use in nested object?
I have some Map extended from HashMap, I dont care of fields order
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
log.warn("Query unknown field " + field);
}
return value;
}
}
And ObjectMapper.readValue return this class
final TypeReference<FieldsMap<String, Object>> mapType =
new TypeReference<FieldsMap<String, Object>>() {};
Map<String, Object> res = new ObjectMapper().readValue("{"a": {"b": 0}}", mapType);
res.get("c"); // warning
But nested object is always LinkedHashMap
System.out.println(res.get("a").getClass().getName()); // java.util.LinkedHashMap
((Map)res.get("a")).get("c"); // no warning
It will be helpful in test environments.
java jackson
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
add a comment |
1
Is there any way to tell jackson library whish Map implementation to use in nested object?
I have some Map extended from HashMap, I dont care of fields order
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
log.warn("Query unknown field " + field);
}
return value;
}
}
And ObjectMapper.readValue return this class
final TypeReference<FieldsMap<String, Object>> mapType =
new TypeReference<FieldsMap<String, Object>>() {};
Map<String, Object> res = new ObjectMapper().readValue("{"a": {"b": 0}}", mapType);
res.get("c"); // warning
But nested object is always LinkedHashMap
System.out.println(res.get("a").getClass().getName()); // java.util.LinkedHashMap
((Map)res.get("a")).get("c"); // no warning
It will be helpful in test environments.
java jackson
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
your json is nested json, and always nested json is with key value pair and treated asMap
– Deadpool
Nov 23 '18 at 7:23
I mean subobjects in json tree, element "a" in my example. Need a comon solution where you dont know tree structure
– lunicon
Nov 23 '18 at 8:23
add a comment |
1
1
1
1
Is there any way to tell jackson library whish Map implementation to use in nested object?
I have some Map extended from HashMap, I dont care of fields order
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
log.warn("Query unknown field " + field);
}
return value;
}
}
And ObjectMapper.readValue return this class
final TypeReference<FieldsMap<String, Object>> mapType =
new TypeReference<FieldsMap<String, Object>>() {};
Map<String, Object> res = new ObjectMapper().readValue("{"a": {"b": 0}}", mapType);
res.get("c"); // warning
But nested object is always LinkedHashMap
System.out.println(res.get("a").getClass().getName()); // java.util.LinkedHashMap
((Map)res.get("a")).get("c"); // no warning
It will be helpful in test environments.
java jackson
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
Is there any way to tell jackson library whish Map implementation to use in nested object?
I have some Map extended from HashMap, I dont care of fields order
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
log.warn("Query unknown field " + field);
}
return value;
}
}
And ObjectMapper.readValue return this class
final TypeReference<FieldsMap<String, Object>> mapType =
new TypeReference<FieldsMap<String, Object>>() {};
Map<String, Object> res = new ObjectMapper().readValue("{"a": {"b": 0}}", mapType);
res.get("c"); // warning
But nested object is always LinkedHashMap
System.out.println(res.get("a").getClass().getName()); // java.util.LinkedHashMap
((Map)res.get("a")).get("c"); // no warning
It will be helpful in test environments.
java jackson
java jackson
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
edited Nov 28 '18 at 20:07
lunicon
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
asked Nov 23 '18 at 7:08
luniconlunicon
93011022
93011022
your json is nested json, and always nested json is with key value pair and treated asMap
– Deadpool
Nov 23 '18 at 7:23
I mean subobjects in json tree, element "a" in my example. Need a comon solution where you dont know tree structure
– lunicon
Nov 23 '18 at 8:23
add a comment |
your json is nested json, and always nested json is with key value pair and treated asMap
– Deadpool
Nov 23 '18 at 7:23
I mean subobjects in json tree, element "a" in my example. Need a comon solution where you dont know tree structure
– lunicon
Nov 23 '18 at 8:23
your json is nested json, and always nested json is with key value pair and treated as
Map– Deadpool
Nov 23 '18 at 7:23
your json is nested json, and always nested json is with key value pair and treated as
Map– Deadpool
Nov 23 '18 at 7:23
I mean subobjects in json tree, element "a" in my example. Need a comon solution where you dont know tree structure
– lunicon
Nov 23 '18 at 8:23
I mean subobjects in json tree, element "a" in my example. Need a comon solution where you dont know tree structure
– lunicon
Nov 23 '18 at 8:23
add a comment |
1 Answer
1
active
oldest
votes
1
You must add a an abstract type mapping to your ObjectMapper. This is done with a module:
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
System.out.println("Query unknown field " + field);
}
return value;
}
public static void main(String args) throws IOException {
final TypeReference<FieldsMap<String, Object>> mapType = new TypeReference<FieldsMap<String, Object>>() {};
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule().addAbstractTypeMapping(Map.class, FieldsMap.class);
objectMapper.registerModule(module);
Map<String, Object> res = objectMapper.readValue("{"a": {"b": 0}}", mapType);
res.get("c");
System.out.println(res.get("a").getClass().getName());
((Map)res.get("a")).get("c");
}
}
This will instruct Jackson to use your custom type FieldsMap each time a Map is needed.
The output is:
Query unknown field c
FieldsMap
Query unknown field c
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
1
You must add a an abstract type mapping to your ObjectMapper. This is done with a module:
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
System.out.println("Query unknown field " + field);
}
return value;
}
public static void main(String args) throws IOException {
final TypeReference<FieldsMap<String, Object>> mapType = new TypeReference<FieldsMap<String, Object>>() {};
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule().addAbstractTypeMapping(Map.class, FieldsMap.class);
objectMapper.registerModule(module);
Map<String, Object> res = objectMapper.readValue("{"a": {"b": 0}}", mapType);
res.get("c");
System.out.println(res.get("a").getClass().getName());
((Map)res.get("a")).get("c");
}
}
This will instruct Jackson to use your custom type FieldsMap each time a Map is needed.
The output is:
Query unknown field c
FieldsMap
Query unknown field c
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
add a comment |
1
You must add a an abstract type mapping to your ObjectMapper. This is done with a module:
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
System.out.println("Query unknown field " + field);
}
return value;
}
public static void main(String args) throws IOException {
final TypeReference<FieldsMap<String, Object>> mapType = new TypeReference<FieldsMap<String, Object>>() {};
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule().addAbstractTypeMapping(Map.class, FieldsMap.class);
objectMapper.registerModule(module);
Map<String, Object> res = objectMapper.readValue("{"a": {"b": 0}}", mapType);
res.get("c");
System.out.println(res.get("a").getClass().getName());
((Map)res.get("a")).get("c");
}
}
This will instruct Jackson to use your custom type FieldsMap each time a Map is needed.
The output is:
Query unknown field c
FieldsMap
Query unknown field c
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
add a comment |
1
1
1
You must add a an abstract type mapping to your ObjectMapper. This is done with a module:
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
System.out.println("Query unknown field " + field);
}
return value;
}
public static void main(String args) throws IOException {
final TypeReference<FieldsMap<String, Object>> mapType = new TypeReference<FieldsMap<String, Object>>() {};
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule().addAbstractTypeMapping(Map.class, FieldsMap.class);
objectMapper.registerModule(module);
Map<String, Object> res = objectMapper.readValue("{"a": {"b": 0}}", mapType);
res.get("c");
System.out.println(res.get("a").getClass().getName());
((Map)res.get("a")).get("c");
}
}
This will instruct Jackson to use your custom type FieldsMap each time a Map is needed.
The output is:
Query unknown field c
FieldsMap
Query unknown field c
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
You must add a an abstract type mapping to your ObjectMapper. This is done with a module:
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class FieldsMap<K, V> extends HashMap<K, V> {
@Override
public V get(Object field) {
V value = super.get(field);
if (value == null && !containsKey(field)) {
System.out.println("Query unknown field " + field);
}
return value;
}
public static void main(String args) throws IOException {
final TypeReference<FieldsMap<String, Object>> mapType = new TypeReference<FieldsMap<String, Object>>() {};
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule().addAbstractTypeMapping(Map.class, FieldsMap.class);
objectMapper.registerModule(module);
Map<String, Object> res = objectMapper.readValue("{"a": {"b": 0}}", mapType);
res.get("c");
System.out.println(res.get("a").getClass().getName());
((Map)res.get("a")).get("c");
}
}
This will instruct Jackson to use your custom type FieldsMap each time a Map is needed.
The output is:
Query unknown field c
FieldsMap
Query unknown field c
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
edited Nov 28 '18 at 15:30
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
answered Nov 28 '18 at 10:18
BenoitBenoit
2,5462929
2,5462929
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
add a comment |
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
I tried. Unfortunately not working.
– lunicon
Nov 28 '18 at 13:53
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
@lunicon It's weird, because it does work for me. I reproduced the exact same sample you provided. What version of Jackson do you use ?
– Benoit
Nov 28 '18 at 13:55
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
dependencies 'com.fasterxml.jackson.core:jackson-core:2.4.2'. Maybe I'm using it in wrong way. Can you provide full example
– lunicon
Nov 28 '18 at 13:58
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
@lunicon I updated my answer with a full working example.
– Benoit
Nov 28 '18 at 15:33
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
I thought that the error was in inner class usage. No, this feature added in later version.. Thanks by the way
– lunicon
Nov 28 '18 at 20:06
add a comment |
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your json is nested json, and always nested json is with key value pair and treated as
Map– Deadpool
Nov 23 '18 at 7:23
I mean subobjects in json tree, element "a" in my example. Need a comon solution where you dont know tree structure
– lunicon
Nov 23 '18 at 8:23