[GitHub] [shardingsphere] coderMmw commented on issue #5208: data fragmentation and separation of reading and writing problem

[GitBox]

coderMmw commented on issue #5208:
URL: https://github.com/apache/shardingsphere/issues/5208#issuecomment-616366447


   singleKeyHashShardingAlgorithm1 class
   `package com.pptv.ucm.dao.sharding;
   
   import 
org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
   import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue;
   import 
org.apache.shardingsphere.api.sharding.standard.RangeShardingAlgorithm;
   import org.apache.shardingsphere.api.sharding.standard.RangeShardingValue;
   
   import java.util.Collection;
   import java.util.HashSet;
   import java.util.Set;
   
   import static java.lang.Math.abs;
   /**
    * 根据单个字段hash来分表的实现
    *
    */
   //public class SingleKeyHashShardingAlgorithm1 implements 
/*SingleKeyTableShardingAlgorithm<String>,*/PreciseShardingAlgorithm, 
RangeShardingAlgorithm<Integer> {
   public class SingleKeyHashShardingAlgorithm1  implements 
PreciseShardingAlgorithm<String>, RangeShardingAlgorithm<Integer> {
   
   
        @Override
        public String doSharding(Collection<String> collection, 
PreciseShardingValue<String> preciseShardingValue) {
   
                // 逻辑表名
                // 根据比较的值，算出物理分表
                String logicTableName = 
preciseShardingValue.getLogicTableName();
                String actualTableName = logicTableName + "_" + 
Math.abs(preciseShardingValue.getValue().hashCode()) % collection.size();
                if (collection.contains(actualTableName)) {
                        return actualTableName;
                } else {
                        // 如果没有匹配到相应的物理表名，那一定是有问题的
                        throw new UnsupportedOperationException();
                }
   
   //   @Override
   //   public String doSharding(Collection collection, PreciseShardingValue 
preciseShardingValue) {
   //           // 逻辑表名
   //           String logicTableName = 
preciseShardingValue.getLogicTableName();
   //           // 根据比较的值，算出物理分表
   //
   //           String actualTableName = logicTableName + "_" + 
Math.abs(preciseShardingValue.getValue().hashCode())% collection.size();
   //           if (collection.contains(actualTableName)){
   //                   return actualTableName;
   //           }else{
   //                   // 如果没有匹配到相应的物理表名，那一定是有问题的
   //                   throw new UnsupportedOperationException();
   //           }
   //
   //
   //           // 如果没有匹配到相应的物理表名，那一定是有问题的
   //
   //   }
   //
   //   @Override
   //   public Collection<String> doSharding(Collection<String> 
availableTargetNames, RangeShardingValue<Integer> shardingValue) {
   //           // in表达式的值对应的数据表
   //           Set<String> inValueTables = new HashSet<String>();
   //
   //
   //           String logicTableName = shardingValue.getLogicTableName();
   //           for (String value : availableTargetNames) {
   //                   String actualTableName = logicTableName + "_" + 
value.hashCode() % availableTargetNames.size();
   //                   if (availableTargetNames.contains(actualTableName)){
   //                           inValueTables.add(actualTableName);
   //                   }
   //           }
   //
   //           if (inValueTables.size() == 0){
   //                   throw new UnsupportedOperationException();
   //           }
   //
   //           return inValueTables;
   //   }
   
   
        }
   
        public static void main(String[] args) {
                String s = null;
                int i = Math.abs("00:25:92:EE:6F:EE".hashCode()) % 10;
                System.out.println(i);
        }
   
   
        @Override
        public Collection<String> doSharding(Collection<String> 
availableTargetNames, RangeShardingValue<Integer> shardingValue) {
                // in表达式的值对应的数据表
                Set<String> inValueTables = new HashSet<String>();
   
   
                String logicTableName = shardingValue.getLogicTableName();
                for (String value : availableTargetNames) {
                        String actualTableName = logicTableName + "_" + 
value.hashCode() % availableTargetNames.size();
                        if (availableTargetNames.contains(actualTableName)){
                                inValueTables.add(actualTableName);
                        }
                }
   
                if (inValueTables.size() == 0){
                        throw new UnsupportedOperationException();
                }
   
                return inValueTables;
        }
   }
   `


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