XML文件
<insert id ="insertBatch" parameterType="java.util.List">
<selectKey resultType ="java.lang.Integer" keyProperty= "id"
order= "AFTER">
SELECT LAST_INSERT_ID()
</selectKey >
INSERT INTO message_user
(user_id, message_id, create_time)
values
<foreach collection ="list" item="model" index= "index" separator =",">
(
#{model.userId}, #{model.messageId}, #{model.createTime}
)
</foreach >
</insert >
JAVA代码
// 部分代码
messageService.insert(message);
int messageId = message.getId();
int size = userIdList.size();
int startIndex = 0;
// MAX_BATCH_REQUEST: 最大批处理请求数
int endIndex = MAX_BATCH_REQUEST;
while (startIndex <= size) {
if (endIndex > size) {
endIndex = size;
}
List<String> subItems = userIdList.subList(startIndex, endIndex);
List<MessageUser> modelList = new ArrayList<>();
for (String obj : subItems) {
if (StringUtils.isEmpty(obj)) continue;
MessageUser mu = new MessageUser();
mu.setUserId(new BigDecimal(obj).intValue());
mu.setMessageId(messageId);
mu.setCreateTime(now);
modelList.add(mu);
}
// 调用Service方法
messageUserService.insertBatch(modelList);
startIndex += MAX_BATCH_REQUEST;
endIndex += MAX_BATCH_REQUEST;
}
TIPS
- 批处理时，应该打点，那样系统中断后可以续存
- 如果是对响应有要求的系统，可以开多个线程，或者另起一个job执行批处理
- 最大请求数不能太大，否则会给DB很大压力
- 关于事务问题
