tiandihai commented on issue #29225:
URL:
https://github.com/apache/shardingsphere/issues/29225#issuecomment-1828943671
import com.google.common.base.Preconditions;
import lombok.extern.slf4j.Slf4j;
import
org.apache.shardingsphere.sharding.api.sharding.hint.HintShardingAlgorithm;
import
org.apache.shardingsphere.sharding.api.sharding.hint.HintShardingValue;
import
org.apache.shardingsphere.sharding.api.sharding.standard.PreciseShardingValue;
import
org.apache.shardingsphere.sharding.api.sharding.standard.RangeShardingValue;
import
org.apache.shardingsphere.sharding.api.sharding.standard.StandardShardingAlgorithm;
import java.nio.charset.StandardCharsets;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.stream.Collectors;
/**
* @Description:
* @author wanglei10
* @date 2023-08-02 11:35
*/
@Slf4j
public class DatabaseShardingAlgorithm implements
StandardShardingAlgorithm<Comparable<?>>, HintShardingAlgorithm<Comparable<?>> {
private final Map<Integer, String> partitionDatabaseMap = new
HashMap<>();
private volatile int partitionSize;
@Override
public void init(Properties properties) {
calculatePartitionRange(properties);
}
private static final String DATABASE_SHARDING_RANGES =
"database-sharding-ranges";
public void calculatePartitionRange(final Properties props) {
Preconditions.checkState(props.containsKey(DATABASE_SHARDING_RANGES), "props:
database-sharding-ranges cannot be null.");
log.info("database-sharding-ranges配置：{}",
props.getProperty(DATABASE_SHARDING_RANGES));
String[] dsConfigs =
props.getProperty(DATABASE_SHARDING_RANGES).split(",");
Preconditions.checkState(dsConfigs.length > 0, "props:
database-sharding-ranges配置错误,配置实例：db-0:0-15,db-1:16-31,db-2:32-47,db-3:48-63");
for (String s : dsConfigs) {
if (s != null && !s.trim().equals("")) {
String[] s1 = s.trim().split(":");
if (s1.length == 2) {
String dsName = s1[0].trim();
String[] s2 = s1[1].trim().split("-");
int start = Integer.parseInt(s2[0].trim());
int end = Integer.parseInt(s2[1].trim());
for (int i = start; i <= end; i++) {
partitionDatabaseMap.put(i, dsName);
}
} else {
log.warn("props: database-sharding-ranges配置可能出现错误:{}",
s);
}
}
}
partitionSize = partitionDatabaseMap.size();
//解析后配置
log.info("database-sharding-ranges解析后配置");
partitionDatabaseMap.entrySet().stream()
.collect(Collectors.groupingBy(Map.Entry::getValue,
Collectors.mapping(Map.Entry::getKey, Collectors.toList())))
.forEach((key, value) -> log.info("数据库：{},哈希值:{}-{}", key,
value.get(0), value.get(value.size() - 1)));
}
@Override
public Collection<String> doSharding(Collection<String>
availableTargetNames, HintShardingValue<Comparable<?>> shardingValue) {
return shardingValue.getValues().stream().map(it ->
routeDatabase(availableTargetNames, it)).collect(Collectors.toList());
}
@Override
public final String doSharding(final Collection<String>
availableTargetNames, final PreciseShardingValue<Comparable<?>> shardingValue) {
return routeDatabase(availableTargetNames, shardingValue.getValue());
}
private String routeDatabase(Collection<String> availableTargetNames,
Comparable<?> value) {
if (value == null) {
throw new RuntimeException("shardingValue不能为空");
}
int slot = (int)
(MurmurHash2.hash32(value.toString().getBytes(StandardCharsets.UTF_8), 2773) &
0xFFFFFFFFL % partitionSize);
String dbName = partitionDatabaseMap.get(slot);
if (dbName == null) {
throw new RuntimeException("database-sharding-ranges配置错误:" +
value + "对应的配置不存在");
}
if (!availableTargetNames.contains(dbName)) {
throw new RuntimeException("database-sharding-ranges配置错误:" +
dbName + "数据库不存在");
}
return dbName;
}
@Override
public final Collection<String> doSharding(final Collection<String>
availableTargetNames, final RangeShardingValue<Comparable<?>> shardingValue) {
return availableTargetNames;
}
@Override
public String getType() {
return "DATABASE-MOD-SHARDING";
}
}
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