有没有人知道com.fasterxml.jackson.databind.ObjectMapper如何将JSON属性映射到不区分大小写的POJO属性?
JSON字符串:
[{" FIRSTNAME":"约翰"" LASTNAME":" Doe的"" DATEOFBIRTH&#34 ;: " 1980-07-16T18:25:00.000Z"}]
POJO级:
public class Person {
private String firstName;
private String lastName;
private Date dateOfBirth;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public Date getDateOfBirth() {
return dateOfBirth;
}
public void setDateOfBirth(Date dateOfBirth) {
this.dateOfBirth = dateOfBirth;
}
}
测试类:
@Test
public final void testDeserializingPersonJsonToPersonClass()
throws JsonParseException, JsonMappingException, IOException {
final String jsonAsString = "[{\"FIRSTNAME\":\"John\",\"LASTNAME\":\"Doe\",\"DATEOFBIRTH\":\"1980-07-16T18:25:00.000Z\"}]";
final ObjectMapper mapper = new ObjectMapper();
final Person person = mapper.readValue(jsonAsString, Person.class);
assertNotNull(person);
assertThat(person.getFirstName(), equalTo("John"));
}
这最终会出现以下错误:
com.fasterxml.jackson.databind.JsonMappingException:无法反序列化...的实例...
不可能既不改变JSON-String也不改变POJO-Class。
答案 0 :(得分:49)
这种行为是在Jackson 2.5.0中引入的。您可以使用MapperFeature将映射器配置为不区分大小写。ACCEPT_CASE_INSENSITIVE_PROPERTIES。
例如:
ObjectMapper mapper = new ObjectMapper();
mapper.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true);
答案 1 :(得分:7)
我遇到了同样的问题,找不到解决这个问题的全球方法。但是,每个属性可以有2个setter来实现此目的:
@JsonSetter("FIRSTNAME")
public void setFirstNameCaps(String firstName) {
this.firstName = firstName;
}
@JsonSetter("firstName")
public void setFirstName(String firstName) {
this.firstName = firstName;
}
不优雅,但适用于大小写json字段。您也可以尝试提及here的解决方案,但这可能会带来性能开销
答案 2 :(得分:3)
package br.com.marcusvoltolim.util;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.log4j.Log4j;
@Log4j
public class JsonUtils {
private static final ObjectMapper OBJECT_MAPPER;
static {
OBJECT_MAPPER = new ObjectMapper();
OBJECT_MAPPER.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true);
OBJECT_MAPPER.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
}
public static <T> T fromJson(final String json, final Class<T> classe) {
try {
return OBJECT_MAPPER.readValue(json, classe);
} catch (Exception e) {
log.error(e);
try {
return classe.newInstance();
} catch (InstantiationException | IllegalAccessException ex) {
return null;
}
}
}
}
答案 3 :(得分:1)
您可以通过配置映射器来解决此问题,如@Nicolas Riousset所述。
此外,自杰克逊2.9版起,您可以在字段或类上使用注释@JsonFormat(with = JsonFormat.Feature.ACCEPT_CASE_INSENSITIVE_PROPERTIES)
来进行相同的操作,这是一种更加灵活的选择。
@JsonFormat(with = JsonFormat.Feature.ACCEPT_CASE_INSENSITIVE_PROPERTIES)
private String firstName;
答案 4 :(得分:0)
我遇到了同样的情况,不得不转换为地图,然后手动复制这些值。
<input
date-range-picker
type="text"
ng-model="scheduledDate"
options="{timePicker: true, timePickerIncrement:30,locale: {format: 'DD/MM/YYYY hh:mm:ss'},separator: '-'}"
/>
$scope.scheduledDate = {startDate:new Date(myDateTime),endDate:new Date(myDateTime)}
答案 5 :(得分:0)
从Jackson版本2.12开始,您终于可以在课程上添加注释:
@JsonFormat(with = JsonFormat.Feature.ACCEPT_CASE_INSENSITIVE_PROPERTIES)
public class Person {
private String firstName;
private String lastName;
private Date dateOfBirth;
// setters and getters ...
}
如Github issue中所述,仍然不支持对单个属性不区分大小写!
答案 6 :(得分:-1)
另一种解决方案是指定区分大小写的JSON字段名称:
public Movie(){
//Jackson deserialize
}
@JsonProperty("Title")
public String getTitle() {
return title;
}
@JsonProperty("Year")
public String getYear() {
return year;
}
@JsonProperty("imdbID")
public String getImdbID() {
return imdbID;
}