是否可能:在类中有一个字段，但在Jackson库中序列化/反序列化期间为它取不同的名称?
例如，我有一个类“coordindiantes”。
class Coordinates{
int red;
}
对于JSON的反序列化，希望有这样的格式:
{
"red":12
}
但是当我序列化对象时，结果应该是这样的:
{
"r":12
}
我试图通过在getter和setter上应用@JsonProperty注释来实现这一点(具有不同的值):
class Coordiantes{
int red;
@JsonProperty("r")
public byte getRed() {
return red;
}
@JsonProperty("red")
public void setRed(byte red) {
this.red = red;
}
}
但我有个例外:
org.codehaus.jackson。map。exx . unrecognizedpropertyexception:无法识别的字段“red”
你可以写一个序列化类来实现:
public class Symbol
{
private String symbol;
private String name;
public String getSymbol() {
return symbol;
}
public void setSymbol(String symbol) {
this.symbol = symbol;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public class SymbolJsonSerializer extends JsonSerializer<Symbol> {
@Override
public void serialize(Symbol symbol, JsonGenerator jgen, SerializerProvider serializers) throws IOException, JsonProcessingException {
jgen.writeStartObject();
jgen.writeStringField("symbol", symbol.getSymbol());
//Changed name to full_name as the field name of Json string
jgen.writeStringField("full_name", symbol.getName());
jgen.writeEndObject();
}
}
ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(Symbol.class, new SymbolJsonSerializer());
mapper.registerModule(module);
//only convert non-null field, option...
mapper.setSerializationInclusion(Include.NON_NULL);
String jsonString = mapper.writeValueAsString(symbolList);
你可以写一个序列化类来实现:
public class Symbol
{
private String symbol;
private String name;
public String getSymbol() {
return symbol;
}
public void setSymbol(String symbol) {
this.symbol = symbol;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public class SymbolJsonSerializer extends JsonSerializer<Symbol> {
@Override
public void serialize(Symbol symbol, JsonGenerator jgen, SerializerProvider serializers) throws IOException, JsonProcessingException {
jgen.writeStartObject();
jgen.writeStringField("symbol", symbol.getSymbol());
//Changed name to full_name as the field name of Json string
jgen.writeStringField("full_name", symbol.getName());
jgen.writeEndObject();
}
}
ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(Symbol.class, new SymbolJsonSerializer());
mapper.registerModule(module);
//only convert non-null field, option...
mapper.setSerializationInclusion(Include.NON_NULL);
String jsonString = mapper.writeValueAsString(symbolList);
使用Jackson 2.9+引入的@JsonAlias进行注释，而不用在要用多个别名(json属性的不同名称)反序列化的项上提到@JsonProperty就可以了。
我使用com.fasterxml.jackson.annotation.JsonAlias与com.fasterxml.jackson.databind.ObjectMapper作为我的用例来实现包的一致性。
例如:
@Data
@Builder
public class Chair {
@JsonAlias({"woodenChair", "steelChair"})
private String entityType;
}
@Test
public void test1() {
String str1 = "{\"woodenChair\":\"chair made of wood\"}";
System.out.println( mapper.readValue(str1, Chair.class));
String str2 = "{\"steelChair\":\"chair made of steel\"}";
System.out.println( mapper.readValue(str2, Chair.class));
}
工作得很好。
对于Kotlin的人:
data class TestClassDTO(
@JsonProperty("user_name")
val username: String
)
你将成功地从RestControllers中的POST有效载荷处理{"user_name": "John"}
但是当您需要用相同的@JsonProperty名称进行序列化时，您可以使用这种反射方法
fun Any.forceSerialize(separator: String, sorted: Boolean = false): String {
var fieldNameToAnnotatedNameMap = this.javaClass.declaredFields.map { it.name }.associateWith { fieldName ->
val jsonFieldName =
this::class.primaryConstructor?.parameters?.first { it.name == fieldName }?.annotations?.firstOrNull { it is JsonProperty }
val serializedName = if (jsonFieldName != null) (jsonFieldName as JsonProperty).value else fieldName
serializedName
}
if (sorted)
fieldNameToAnnotatedNameMap = fieldNameToAnnotatedNameMap.toList().sortedBy { (_, value) -> value}.toMap()
return fieldNameToAnnotatedNameMap.entries.joinToString(separator) { e ->
val field = this::class.memberProperties.first { it.name == e.key }
"${e.value}=${field.javaGetter?.invoke(this)}"
}
}
