Auto-mapping Enums

In addition to MyBatis’s EnumOrdinalTypeHandler (based on enum constant ordinal) and EnumTypeHandler (based on enum constant name),
we provide a more flexible enum handler: MybatisEnumTypeHandler (based on enum constant properties).
Simply declare the enum to enable auto-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 the enum to use MybatisEnumTypeHandler (based on enum constant properties) for mapping.

Method 1: Annotation Marking

Use the @EnumValue annotation on enum properties 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, "Primary School"),
    SECONDARY(2, "Secondary School"),
    HIGH(3, "High School");

    @EnumValue // Marks the value stored in the database as 'code'
    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, "One year old"),
    TWO(2, "Two years old"),
    THREE(3, "Three years old");

    private final int value;
    private final String desc;

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

Undeclared Enums

Undeclared enums will use MyBatis’s defaultEnumTypeHandler, which defaults to EnumTypeHandler.
You can modify the global configuration to change this, but it will not affect enums declared using the above methods.

Modifying the Global defaultEnumTypeHandler

Configure in the 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.

Extra Reference: How to Serialize Enum Values for Frontend Responses

Jackson

1. Override the 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 the enum. Choose either of the above two approaches.

2. Annotation Processing

public enum GradeEnum {
    PRIMARY(1, "Primary School"),
    SECONDORY(2, "Secondary School"),
    HIGH(3, "High School");

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

    @EnumValue
    @JsonValue // Marks the JSON response value
    private final int code;
}

Fastjson

1. Override the toString Method

Global Approach

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

Local Approach

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

Override the toString method in the enum. Choose either of the above two approaches.

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