MyBatis自带两种(EnumOrdinalTypeHandler和EnumTypeHandler)枚举转换器，但只支持最基本的枚举类型

与ordinal属性相互转换

EnumOrdinalTypeHandler可将枚举的ordinal属性和int相互转换

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enum GenderEnum{MALE,FEMALE}

会将GenderEnum.MALE转为0，GenderEnum.FEMALE转为1（可相互转换）

与名称相互转换

EnumTypeHandler可将枚举的名称和string相互转换

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enum GenderEnum{MALE,FEMALE}

会将GenderEnum.MALE转为"MALE"，GenderEnum.FEMALE转为"FEMALE"（可互相转换）

自定义转换

对于复杂的Enum则需要自定义转换器

复杂枚举
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//复杂枚举
enum GenderEnum{
    MALE(1,"male"),
    FEMAIL(2,"female");

    private Map<int, GenderEnum> map = new HashMap<>();

    static{
        for(GenderEnum g:GenderEnum.values()){
            map.put(g.getKey,g);
    }

    private int key;
    private String value;

    GenderEnum(int key, String value){
        this.key=key;
        this.value=value;
    }

    public GenderEnum getGenderByKey(int key){
        return map.get(key);
    }
    public int getKey(){
        return key;
    }
}
自定义枚举转换器
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//自定义转换器
public class GenderEnumTypeHandler extends BaseTypeHandler<GenderEnum> {

    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, GenderEnum parameter, JdbcType jdbcType) throws SQLException {
        ps.setInt(i, parameter.getKey());
    }

    @Override
    public GenderEnum getNullableResult(ResultSet rs, String columnName) throws SQLException {
        int key = rs.getInt(columnName);
        if (rs.wasNull()) {
            return null;
        }
        return GenderEnum.getGenderByKey(key);
    }

    @Override
    public GenderEnum getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        int key = rs.getInt(columnIndex);
        if (key == 0 && rs.wasNull()) {
            return null;
        }
        return Method.getGenderByKey(key);
    }

    @Override
    public GenderEnum getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        int key = cs.getInt(columnIndex);
        if (key == 0 && cs.wasNull()) {
            return null;
        }
        return Method.getGenderByKey(key);
    }
}