如何在Java中定义JSON字段名称的命名约定？

The FieldNamingPolicy can be used to define a few standard naming conventions for JSON field names and it can be used in conjunction with GsonBuilder to configure a Gson instance to properly translate Java field names into the desired JSON field names. We can use the setFieldNamingPolicy() method of GsonBuilder to configure a specific naming policy strategy to an object's field during serialization and deserialization.

Gson supports various field naming requirements with following field naming policies

• FieldNamingPolicy.IDENTITY: It uses the exact same naming as the Java model when it serializes an object.
• FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES: It modifies a Java field name from its camel-cased form to a lower case field name where each word is separated by an underscore(_).
• FieldNamingPolicy.LOWER_CASE_WITH_DASHES: It modifies the Java field name from its camel-cased form to a lower case field name where each word is separated by a dash(-).
• FieldNamingPolicy.UPPER_CAMEL_CASE: It will ensure that the first "letter" of the Java field name is capitalized when serialized to its JSON form.
• FieldNamingPolicy.UPPER_CAMEL_CASE_WITH_SPACES: It will ensure that the first "letter" of the Java field name is capitalized when serialized to its JSON form and the words will be separated by a space.

Example

import com.google.gson.*;
import java.sql.Date;
import java.time.LocalDate;
public class FieldNamingPolicyTest {
public static void main(String[] args) {
Gson gson = new GsonBuilder().setPrettyPrinting().setDateFormat("yyyy-MM- dd") .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_DASHES).create();
Person p = new Person("Raja", "Ramesh", 30, Date.valueOf(LocalDate.of(1988, 1, 1)));
String jsonStr = gson.toJson(p);
System.out.println(jsonStr);
}
}
// Person class
class Person {
private String fistName;
private String lastName;
private int _age;
private Date dateOfBirth;
public Person(String fistName, String lastName, int _age, Date dateOfBirth) {
super();
this.fistName = fistName;
this.lastName = lastName;
this._age = _age;
this.dateOfBirth = dateOfBirth;
}
}

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输出

{
"fist-name": "Raja",
"last-name": "Ramesh",
"_age": 30,
"date-of-birth": "1988-01-01"
}

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