Elastic-Job分片
AbstractElasticJob在执行job的时候会获取分片内容JobExecutionMultipleShardingContext,通过shardingService.shardingIfNecessary()进行分片。分片默认得分片策略是均分算法AverageAllocationJobShardingStrategy.sharding(),获取本机的分片序列号shardingService.getLocalHostShardingItems(),并把分片序列号进行set。我们在写具体的业务job,实现process方法时候,可以通过shardingContext获取分片序列号shardingItems。
例如:
投标分10片,那么每台服务器都会获取到对应的分片序列号。当一台服务器那么分片序列号是0,1,2,3,4,5,6,7,8,9,当两台服务器的时候分片序列号是服务器A-0,1,2,3,4服务器B-5,6,7,8,9,实现可以根据查询业务数据进行进行%10取余,如果取到的余在获取的分片序列号内进行投标处理,如果不在则不处理。投标考虑标id和账户id都进行%10是否在满足分片进行具体的投标处理。
序列号对应参数配置shardingItemParameters
部分代码片度如下:
均分策略AverageAllocationJobShardingStrategy
附测试代码:
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import com.alibaba.fastjson.JSONObject;
import com.beust.jcommander.internal.Lists;
import com.dangdang.ddframe.job.internal.sharding.strategy.JobShardingStrategyOption;
import com.google.common.collect.Maps;
public class Testss {
public static void main(String[] args) {
List
serversList.add("ip1");
serversList.add("ip2");
int shardingTotalCount = 10;
Map
JobShardingStrategyOption option = new JobShardingStrategyOption("autoLoanBid", shardingTotalCount, shardingItemParameters);
Map
System.out.println(JSONObject.toJSONString(map));
}
public static Map
if (serversList.isEmpty()) {
return Collections.emptyMap();
}
Map
addAliquant(serversList, option.getShardingTotalCount(), result);
return result;
}
private static Map
Map
int itemCountPerSharding = shardingTotalCount / serversList.size();
int count = 0;
for (String each : serversList) {
List
for (int i = count * itemCountPerSharding; i < (count + 1) * itemCountPerSharding; i++) {
shardingItems.add(i);
}
result.put(each, shardingItems);
count++;
}
return result;
}
private static void addAliquant(final List
int aliquant = shardingTotalCount % serversList.size();
int count = 0;
for (Entry
if (count < aliquant) {
entry.getValue().add(shardingTotalCount / serversList.size() * serversList.size() + count);
}
count++;
}
}
}