[开发工具]MybatisPlus 自定义TypeHandler映射JSON类型为List

示例

自定义映射处理类

@MappedTypes({List.class})
@MappedJdbcTypes({JdbcType.VARCHAR})
public abstract class ListJsonTypeHandler<T> extends BaseTypeHandler<List<T>> {
    /**
     * 具体类型，由子类提供
     *
     * @return 具体类型
     */
    protected abstract TypeReference<List<T>> specificType();

    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, List<T> parameter, JdbcType jdbcType) throws SQLException {
        String content = CollUtil.isEmpty(parameter) ? null : JSON.toJSONString(parameter);
        ps.setString(i, content);
    }

    @Override
    public List<T> getNullableResult(ResultSet rs, String columnName) throws SQLException {
        return this.getListByJsonArrayString(rs.getString(columnName));
    }

    @Override
    public List<T> getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        return this.getListByJsonArrayString(rs.getString(columnIndex));
    }

    @Override
    public List<T> getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        return this.getListByJsonArrayString(cs.getString(columnIndex));
    }

    private List<T> getListByJsonArrayString(String content) {
        return StrUtil.isBlank(content) ? new ArrayList<>() : JSON.parseObject(content, this.specificType());
    }
}

具体的类

public class FileInfoJsonTypeHandler extends ListJsonTypeHandler<FileInfoDTO> {
    @Override
    protected TypeReference<List<FileInfoDTO>> specificType() {
        return new TypeReference<List<FileInfoDTO>>() {
        };
    }
}

最后