sharding proxy自定义分片规则 standard算法 preciseAlgorithmClassName属性

 <!-- sharding-jdbc依赖 -->
        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>sharding-jdbc-core</artifactId>
            <version>4.0.0-RC1</version>
        </dependency>

package com;

import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import static java.lang.System.out;

/**
 * @author :zhangyantao
 * @date : 2020/6/9 18:20
 **/
public class CustomShardingTest implements PreciseShardingAlgorithm<String> {
    /**
     * 数据库前缀
     */
    private static final String PREFIX = "ds_";
    /**
     * 自定义库名配置
     */
    private static Map<String, String> map = new HashMap<String, String>();

     static {
        map.put("420216", "370201");
    }

    /**
     * availableTargetNames 被查到的库列表
     * preciseShardingValue 分片列的值
     */
    @Override
    public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<String> preciseShardingValue) {

        if (preciseShardingValue != null) {
            out.println("availableTargetNames:"+availableTargetNames.toString());
            out.println("preciseShardingValue:"+preciseShardingValue.toString());
            String value = preciseShardingValue.getValue();
            for (String name : availableTargetNames) {
                out.println("value:"+value);
                if (null != map.get(value) && map.get(value).trim().length() > 0) {
                    //特定分片值处理
                    value = map.get(value);
                }
                String newName = PREFIX + Integer.parseInt(value) / 10000;
                out.println("name:"+name);
                out.println("newName:"+newName);
                if (newName.equals(name)) {
                    return name;
                }
            }
            throw new UnsupportedOperationException("没有匹配到可用库");
        } else {
            throw new UnsupportedOperationException("分片列为空");
        }
    }
}

      databaseStrategy:
        standard:
          shardingColumn: STR_AREA_CODE
          preciseAlgorithmClassName: com.CustomShardingTest