springboot~mybatis枚举映射 - 好文

在mybatis和mybatis plus里，如果你的实体字段是一个枚举类型，而在数据表里是整型，这时在存储时需要进行处理，默认情况下，会把枚举的元素名称
拼接到SQL语句里，而由于数据表是int类型，所以在插入等操作时，就会出现异常！

添加枚举处理器
MappedTypes(value = {YesOrNo.class}) public class UniversalEnumHandler<E
extends Enum<E> & BaseEnum> extends BaseTypeHandler<E> { private final Class<E>
type; /** * construct with parameter. */ public UniversalEnumHandler(Class<E>
type) { if (type == null) { throw new IllegalArgumentException("Type argument
cannot be null"); } this.type = type; } @Override public void
setNonNullParameter(PreparedStatement ps, int i, E parameter, JdbcType
jdbcType) throws SQLException { ps.setInt(i, parameter.getCode()); } @Override
public E getNullableResult(ResultSet rs, String columnName) throws SQLException
{ int code = rs.getInt(columnName); return rs.wasNull() ? null :
EnumUtils.codeOf(this.type, code); } @Override public E
getNullableResult(ResultSet rs, int columnIndex) throws SQLException { int code
= rs.getInt(columnIndex); return rs.wasNull() ? null :
EnumUtils.codeOf(this.type, code); } @Override public E
getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
int code = cs.getInt(columnIndex); return cs.wasNull() ? null :
EnumUtils.codeOf(this.type, code); } }
在配置文件指定处理器
mybatis-plus: typeHandlersPackage: cn.pilipa.account.cerebrum.client.enums
#处理器所在包，我是把枚举处理器放在枚举包里
定义代表枚举键值的接口
public interface BaseEnum<E extends Enum<?>, T> { public Integer getCode();
public String getText(); }
定义一下枚举
public enum YesOrNo implements BaseEnum { Yes(1, "是"), No(0, "否"); private
Integer code; private String text; YesOrNo(Integer code, String text) {
this.code = code; this.text = text; } @JsonCreator public static YesOrNo
jsonCreate(Integer code) { return EnumUtils.codeOf(YesOrNo.class, code); }
@Override public Integer getCode() { return this.code; } @Override public
String getText() { return this.text; } @JsonValue public Integer getCodeStr() {
return this.code; } }
在实体中定义枚举类型字段
/** * 是否为国民. */ private YesOrNo naturalBorn;
生成的SQL语句
==> Preparing: INSERT INTO employee_info ( id, name, credit_number, status,
first_time, tax_code, natural_born ) VALUES ( ?, ?, ?, ?, ?, ?, ? ) 2019-09-05
16:56:38.991 DEBUG [accounting-client,,,] 92833 --- [ main]
c.p.a.c.c.m.EmployeeInfoMapper.insert : ==> Parameters:
1169534796253630466(Long), 段会涛(String), 130523199011111219(String), 1(Integer),
2019-09-05(Date), 130523199011111219(String), 0(Integer)
从上面结果中看到，我们的natural_born对应的值已经是int类型了，表示处理器成功了！

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