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Question

我使用Freemarker模板引擎生成一个插入Postgres的语句，其中包含来自csv文件的数据。数据库中有一个日期类型的列（＆＃39; birthdate＆＃39; ），如果该值不存在，插入应包含NULL（以安抚Postgres）或实际的生日，如果提供。像这样的东西：

INSERT INTO web_iws.broker (id,create_timestamp,update_timestamp,sfid,deleted,account_name,first_name,last_name,title,ssn,phone,mobile_phone,fax,email,mailing_street,mailing_city,mailing_state,mailing_postal_code,mailing_country,broker_number,npn,ga,ga_number,birthdate,appointed,indor_corp) VALUES(nextval('web_iws.broker_id_seq'::regclass),now(),now(),'003i00234597gnNAAQ',FALSE,'001i045681aYEiMAAW','Mason','Demarcove','Broker','','','','','mrdemarcove@abc.com','','','','','','BRN7J0943','','Savoy Associates','NJGA0306',NULL,'Appointed','');

INSERT INTO web_iws.broker (id,create_timestamp,update_timestamp,sfid,deleted,account_name,first_name,last_name,title,ssn,phone,mobile_phone,fax,email,mailing_street,mailing_city,mailing_state,mailing_postal_code,mailing_country,broker_number,npn,ga,ga_number,birthdate,appointed,indor_corp) VALUES(nextval('web_iws.broker_id_seq'::regclass),now(),now(),'003i07852RjON3sRN',FALSE,'001i0002'43567AAV','Maritza','Galsh','','145-98-1794','','','','marytza@galshben.com','718 River Road','Red Bank','NJ','07701','','BRNJ0877','7420702','Walsh Benefits','NJGA0008','1939-12-03','Appointed','Indv');

Freemarker中有更优雅的东西来表达上述要求：

"<#if birthdate?has_content>'${birthdate}',<#else>NULL,</#if>"

也许内置的日期能够用可配置的默认值或某种三元表达式替换空值，以便删除if ... ...

提前谢谢。

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我尝试了@ddekany发布的建议，这是我看到的：

具有空生日值的随机原始数据记录（在csv中）（ NJGA0001，指定之间的空格）如下所示：

2015-07-28T19:59:09.000Z,2015-07-28T19:59:15.000Z,003i000002oQSRMAA4,FALSE,Centerpoint Consulting,Briant,Hlonan,,,(973) 522-7886,,,briant@centerpointbenefits.com,,,,,,BRNJ0780,,BenefitMall,NJGA0001,,Appointed,Individual

试用时：

"${birthdate?has_content?then(\"'${birthdate}'\", 'NULL')}"+

在我的Java模板中，我收到了错误消息：

11:52:37.168 [main] DEBUG util.BrokerInsertGeneratorTest - Error during saml template buildingfreemarker.core.ParseException: Error on line 1, column 672, in template insertProducingTemplate
Found then, expecting one of:  chunk,  is_date,  last,  root,  j_string,  contains,  is_hash,  long,  float,  ends_with,  namespace,  matches,  time,  values,  seq_last_index_of,  uncap_first,  byte,  substring,  is_transform,  web_safe,  groups,  seq_contains,  is_macro,  index_of,  word_list,  int,  is_method,  eval,  parent,  xml,  number,  capitalize,  if_exists,  rtf,  node_type,  double,  is_directive,  url,  size,  default,  is_boolean,  split,  node_name,  is_enumerable,  seq_index_of,  is_sequence,  sort,  is_node,  sort_by,  left_pad,  cap_first,  interpret,  children,  node_namespace,  chop_linebreak,  date,  short,  last_index_of,  is_collection,  ancestors,  length,  trim,  datetime,  is_string,  reverse,  c,  keys,  upper_case,  js_string,  has_content,  right_pad,  replace,  is_hash_ex,  new,  is_number,  is_indexable,  lower_case,  string,  exists,  html,  first,  starts_with

使用此表达式：

"${(\"'${birthdate}',\")!'NULL'}"+

产生以下内容：

INSERT INTO web_iws.broker (id,create_timestamp,update_timestamp,sfid,deleted,account_name,first_name,last_name,title,ssn,phone,mobile_phone,fax,email,mailing_street,mailing_city,mailing_state,mailing_postal_code,mailing_country,broker_number,npn,ga,ga_number,birthdate,appointed,indor_corp) VALUES(nextval('web_iws.broker_id_seq'::regclass),now(),now(),'003i000002oQSRMAA4',FALSE,'Centerpoint Consulting','Briant','Hlonan','','','(973) 522-7886','','','briant@centerpointbenefits.com','','','','','','BRNJ0780','','BenefitMall','NJGA0001','','Appointed','Individual');

哪个更好，因为它会创建＆＃39; NJGA0001＆＃39;＆＃39;＆＃39;＆＃39;＆＃39;＆＃39;指定＆＃39; ，但不会成为Postgres接受 - 对于空日期字段，它需要NULL。

我愿意听取其他建议。

这里是Java模板字符串，它在处理if语句时需要较少的详细程度：

public final static String templateStr = "INSERT INTO web_iws.broker (id,create_timestamp,update_timestamp,"
            + "sfid,deleted,account_name,first_name,last_name,title,ssn,phone,mobile_phone,fax,email,mailing_street,mailing_city,mailing_state,mailing_postal_code,mailing_country,broker_number,npn,ga,ga_number,birthdate,appointed,indor_corp) "+
 "VALUES(nextval('web_iws.broker_id_seq'::regclass),now(),now(),"+
"'${sfid}',"+
"${deleted},"+
"'${account_name}',"+
"'${first_name}',"+
"'${last_name}',"+
"'${title}',"+
"'${ssn}',"+
"'${phone}',"+
"'${mobile_phone}',"+
"'${fax}',"+
"'${email}',"+
"'${mailing_street}',"+
"'${mailing_city}',"+
"'${mailing_state}',"+
"'${mailing_postal_code}',"+
"'${mailing_country}',"+
"'${broker_number}',"+
"'${npn}',"+
"'${ga}',"+
"'${ga_number}',"+
"<#if birthdate?has_content>'${birthdate}',<#else>NULL,</#if>"+
"'${appointed}',"+
"'${indor_corp}');";

Answer 1

您可以使用postgres'to_char功能。例如：

<#if birthdate?has_content>to_char('${birthdate}', 'YYYY-MM-DD'),<#else>NULL,</#if>

http://www.postgresql.org/docs/current/static/functions-formatting.html

Answer 2

没有三元运算符，但有一个等价的内置函数：

${birthdate?has_content?then("'${birthdate}'", 'NULL')}

还有一个专门的运算符来为缺失值提供默认值，例如someValue!defaultValue。你的情况有点棘手，因为你需要添加这些引号，所以它会像：

${("'${birthdate}'")!'NULL'}

此外，请注意!运算符不会将空字符串视为缺失，与?has_content不同。

最后，如果你做了很多，可能值得为它定义一个#function。

FreeMarker中日期的默认值

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2 个答案: