Auto-Mapping Enums

In addition to MyBatis’s built-in EnumOrdinalTypeHandler (based on enum constant ordinal) and EnumTypeHandler (based on enum constant name), we provide a more flexible enum processor: MybatisEnumTypeHandler (based on enum constant properties).
Simply declare your enums to enable automatic enum mapping.
Undeclared enums will be mapped according to MyBatis’s defaultEnumTypeHandler, which defaults to EnumTypeHandler.

public class User {
    private String name; // Name
    private AgeEnum age; // Age
    private GradeEnum grade; // Grade
}

Enum Declaration

Declare that the enum should be mapped using MybatisEnumTypeHandler (based on enum constant properties).

Method 1: Annotation Marking

Use the @EnumValue annotation on the enum field to specify the actual value stored in the database. Supports any field in the enum class, such as ordinal or code.

@Getter
@AllArgsConstructor
public enum GradeEnum {
    PRIMARY(1, "小学"),
    SECONDARY(2, "中学"),
    HIGH(3, "高中");

    @EnumValue // Marks the code as the value stored in the database
    private final int code;
    // Other properties...
}

Method 2: Interface Implementation

Implement the IEnum interface and override the getValue method to specify the actual value stored in the database. Supports any field in the enum class, such as ordinal or code.

@Getter
@AllArgsConstructor
public enum AgeEnum implements IEnum<Integer> {
    ONE(1, "一岁"),
    TWO(2, "二岁"),
    THREE(3, "三岁");

    private final int value;
    private final String desc;

    @Override
    public Integer getValue() {
        return this.value;
    }
}

Undeclared Enums

Undeclared enums will be mapped using MyBatis’s defaultEnumTypeHandler, which defaults to EnumTypeHandler.
You can modify this via global configuration, but this won’t affect enums declared using the methods above.

Modifying the Global defaultEnumTypeHandler

Configure in YML file:

mybatis-plus:
  configuration:
    default-enum-type-handler: xx.xx.xx.MyEnumTypeHandler

Or via a custom configuration class:

@Configuration
public class MybatisPlusAutoConfiguration {

    @Bean
    public MybatisPlusPropertiesCustomizer mybatisPlusPropertiesCustomizer() {
        return properties -> {
            GlobalConfig globalConfig = properties.getGlobalConfig();
            globalConfig.setBanner(false);
            MybatisPlusProperties.CoreConfiguration configuration = new MybatisPlusProperties.CoreConfiguration();
            configuration.setDefaultEnumTypeHandler(MyEnumTypeHandler.class);
            properties.setConfiguration(configuration);
        };
    }
}

Or other methods.

Additional Reference: Serializing Enum Values for Frontend Responses

Jackson

Method 1: Override toString Method

Spring Boot

@Bean
public Jackson2ObjectMapperBuilderCustomizer customizer() {
    return builder -> builder.featuresToEnable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
}

Standalone Jackson

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(SerializationFeature.WRITE_ENUMS_USING_TO_STRING, true);

Override the toString method in your enum class. Choose either of the above configuration methods.

Method 2: Annotation Processing

public enum GradeEnum {
    PRIMARY(1, "小学"),
    SECONDORY(2, "中学"),
    HIGH(3, "高中");

    GradeEnum(int code, String descp) {
        this.code = code;
        this.descp = descp;
    }

    @EnumValue
    @JsonValue // Marks the field for JSON serialization
    private final int code;
}

Fastjson

Method 1: Override toString Method

Global Configuration

FastJsonConfig config = new FastJsonConfig();
config.setSerializerFeatures(SerializerFeature.WriteEnumUsingToString);

Local Configuration

@JSONField(serialzeFeatures = SerializerFeature.WriteEnumUsingToString)
private UserStatus status;

Override the toString method in your enum class. Choose either of the above configuration methods.

By following these steps, you can elegantly use enum properties in MyBatis-Plus and easily serialize enum values into the format required by your frontend.

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