最近在项目中有这么一段代码：下载服务器基础业务数据进行本地批量插入操作，因项目中使用mybatis进行持久化操作，故直接考虑使用mybatis的批量插入功能。
1.以下是Mapper接口的部分代码
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public interface PrintMapper
{
@InsertProvider(type = PrintMapperProvider.class,method = "insertAllLotWithVehicleCode4H2") void insertAllLotWithVehicleCode(List<LotWithVehicleCodeBO> lotWithVehicleCodes);
}
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2.对应MapperProvider中函数片段
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public String insertAllLotWithVehicleCode4H2(Map<String,List<LotWithVehicleCodeBO>> map)
{
List<LotWithVehicleCodeBO> lotWithVehicleCodeBOs = map.get("list");
StringBuilder sb = new StringBuilder("INSERT INTO MTC_LOT_WITH_VEHICLE_CODE (LOT_CODE,PRODUCT_VEHICLE_CODE) VALUES ");
"#'{'list[{0}].lotCode }," +
"#'{'list[{0}].productVehicleCode }" +
")"); int size = lotWithVehicleCodeBOs.size(); for (int i = 0; i < size; i++)
{
sb.append(messageFormat.format(new Object[]{i}));
if (i < size - 1) sb.append(",");
}
return sb.toString();
}
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3.service层
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@Transactionalpublic void synchLotWithVehicleCodeToLocalDB(List<LotWithVehicleCodeBO> lotWithVehicleCodeBOs)
{ if(null != lotWithVehicleCodeBOs && lotWithVehicleCodeBOs.size()>0)
{
printMapper.insertAllLotWithVehicleCode(lotWithVehicleCodeBOs);
}
}
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程序上线的时候没有发生问题，在业务量猛增的时候，大约同时执行500条以上的时候程序就开始报错：
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Caused by: org.apache.ibatis.builder.BuilderException: Improper inline parameter map format. Should be: #{propName,attr1=val1,attr2=val2}
at org.apache.ibatis.builder.SqlSourceBuilder$ParameterMappingTokenHandler.buildParameterMapping(SqlSourceBuilder.java:89)
at org.apache.ibatis.builder.SqlSourceBuilder$ParameterMappingTokenHandler.handleToken(SqlSourceBuilder.java:43)
at org.apache.ibatis.parsing.GenericTokenParser.parse(GenericTokenParser.java:25)
at org.apache.ibatis.builder.SqlSourceBuilder.parse(SqlSourceBuilder.java:24)
at org.apache.ibatis.builder.annotation.ProviderSqlSource.createSqlSource(ProviderSqlSource.java:57)
... 61 more
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异常已指明SQL语句构建问题，DEBUG进去：
问题根源：
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MessageFormat messageFormat = new MessageFormat("(" +
"#'{'list[{0}].lotCode }," +
"#'{'list[{0}].productVehicleCode }," +
")");
int size = lotWithVehicleCodeBOs.size();
for (int i = 0; i < size; i++)
{
sb.append(messageFormat.format(new Object[]{i}));
if (i<size-1) sb.append(",");
}
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当size达到3位数以上时构建出的message为：
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(#{list[1,000].lotCode },#{list[1,000].productVehicleCode })
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解决办法：messageFormat.format(new Object[]{i+""}