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; } }登录后复制