简化mybatis @Select IN条件的编写
最近从JPA切换到Mybatis，使用无XML配置，@Select注解直接写到interface上，发现IN条件的编写相当麻烦。
一般得写成这样：
@Select({"<script>","SELECT *", "FROM blog","WHERE id IN", "<foreach item='item' index='index' collection='list'","open='(' separator=',' close=')'>","#{item}","</foreach>","</script>"})
List<Blog> selectBlogs(@Param("list") int[] ids);写的看起来很别扭，原来JPA+Hibernate写HQL就不用额外处理。想着找一下解决方案，一搜确实也有人有同样的痛点。
原来我写的是这样的：
@Select("select distinct(USER_ID) from SYS_LOGIN_LOG " +"where USER_ID IN (#{userIds}) " +"and TENANT_ID = #{tenantId} " +"and CREATE_TIME between #{startTime} and #{endTime}")List<Long> selectInTimeRange(@Param("userIds") long[] userIds, @Param("tenantId") long tenantId,@Param("startTime") Date startTime, @Param("endTime") Date endTime);发现解析失败，google了一下，通过增加一个语法处理器就解决了。
在Mapper基类添加这样的处理器
public interface CcBaseMapper<T> extends BaseMapper<T> {/*** 解决mybatis in条件写得难看的问题*/class InConditionDriver extends XMLLanguageDriverimplements LanguageDriver {private final Pattern inPattern = Pattern.compile("\\(#\\{(\\w+)\\}\\)");public SqlSource createSqlSource(Configuration configuration, String script, Class<?> parameterType) {Matcher matcher = inPattern.matcher(script);if (matcher.find()) {script = matcher.replaceAll("(<foreach collection=\"$1\" item=\"__item\" separator=\",\" >#{__item}</foreach>)");}script = "<script>" + script + "</script>";return super.createSqlSource(configuration, script, parameterType);}}
然后添加这个处理器即可：
@Lang(InConditionDriver.class)@Select("select distinct(USER_ID) from SYS_LOGIN_LOG " +"where USER_ID IN (#{userIds}) " +"and TENANT_ID = #{tenantId} " +"and CREATE_TIME between #{startTime} and #{endTime}")List<Long> selectInTimeRange(@Param("userIds") long[] userIds, @Param("tenantId") long tenantId,@Param("startTime") Date startTime, @Param("endTime") Date endTime);这样就不报错了。搞掂