开源，从关注产品社区做起（ibatis3.x的最近一个issue展示）
题记：
??? “低碳从拔下插头做起”，开源，从关注产品社区做起：）
??? 发这个贴的的缘由是看了jnn大哥发的一篇关于开源软件的帖子http://www.iteye.com/topic/277696，虽然是08年写的，但里面说到follow社区的mail list的建议是不错的，想想自己还未奉献过代码，于是去ibaits的google社区瞅了一眼，其实只要你行动，提交一个被accepted的issue并不是那么困难。
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???以下就是展现一个最新被ibatis3.x接受的建议。（当然不是我commit的，希望以后有机会吧）
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Reported by clinton.begin, May 17, 2010
Reporter:? Travis Hein?
Would it be possible to create a new annotation (or does one exist already
and I just have not found it yet), where I can specify that @Select results
should be a <resultMap> that exists in the mapper XML file ?
可以不可以为@select新增一个注解用于重用resultMap配置中定义的map。
For example,
比如：
Consider a "country" table,
CREATE TABLE COUNTRY( ID bigint PRIMARY KEY NOT NULL, CODE varchar(2) NOT NULL, ISO_CODE varchar(3) NOT NULL, NAME varchar(2147483647), COUNTRY_CODE varchar(10), ACTIVE boolean DEFAULT TRUE NOT NULL);
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And the java Bean,
public class Country { Long id; String code; // 2 digit ISO country code String isoCode; // 3 digit ISO country code String name; // string name String countryCode; // the telephone dialing prefix (e.g. +1) boolean active = true; // and all the get() set() methods for these bean properties}?
And then the mapper interface,
public interface CountryDAO { /** * Selects all country entries. * Though it appears when we use the annotations, we need to specify theresults every time ? */ @Select( value = { "select * from country where active = true" }) @Results(value = { @Result(property="id"), @Result(property="code"), @Result(property="isoCode", column="iso_code"), @Result(property="name", column="name"), @Result(property="countryCode", column="country_code"), @Result(property="active", column="active") }) List<Country> getAllActive(); // TODO: all these methods would also be select queries, where I wouldwant the same results map as above Country getById(Long id); Country getByCode(String code); Country getByIsoCode(String isoCode);}?
这里每个方法都需要重复添加如上返回的map定义，就显的很冗余了。
Where, instead of the @Results annotation, which would need to be
duplicated with its nested @Result annotations on every select method that
I want to return the same mapping, what I would wish to have would be
something like a
@ResultMap(value="myMapperID") 作者想添加这个注解，替代上面的重复定义。
annotation, where the myMapperID would be the ID of a <resultMap> I have
declared in the mapper's xml file that will be included by the
SqlMapConfig.xml (which I have anyway to bind to this mapper interface, and
also because I have some more complex queries declared in the xml mapper
file too).
Where in this example, I already have a
<mapper namespace="CountryDAO"><resultMap type="Country" id="countryResult"><result property="id" column="id"/><result property="code" column="code"/><result property="isoCode" column="iso_code"/><result property="name" column="name"/><result property="countryCode" column="country_code"/><result property="active" column="active"/></resultMap>
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So this wishful @ResultMap annotation would then make the mapper interface
look like:
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修改后的代码变为：
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public interface CountryDAO { @Select( value = { "select * from country where active = true" }) @ResultMap(value = "countryResult") List<Country> getAllActive(); // and now other things that want to select into this map can do so,re-using the single map declaration // that is referenced in the xml. @Select( value = { "select * from country where id = #{id} }) @ResultMap(value = "countryResult") Country getById(Long id); @Select( value = { "select * from country where code = #{code} }) @ResultMap(value = "countryResult") Country getByCode(String code); @Select( value = { "select * from country where isoCode = #{isoCode} }) @ResultMap(value = "countryResult") Country getByIsoCode(String isoCode);}?
I think having something like this @ResultMap annotation would be a good
thing to have, what do you think?
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?看到countryResult这个map已经在xml文件中定义好了，无需再每个方法前面重复定义了，只要声明就ok了。
1 楼 IcedCoffee 2010-08-31 没用过ibatis的annotation 2 楼 tedeyang 2010-08-31 很好的改进，不过话说回来，mybatis用annotation是走上邪路了。sql又跑回java代码里，那我还不如用sql template 3 楼 chan.d 2010-08-31 tedeyang 写道很好的改进，不过话说回来，mybatis用annotation是走上邪路了。sql又跑回java代码里，那我还不如用sql template