sharding

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sharding

一、在最开始提到了GroupIDAndCollectTimeDBShardingAlgorithm分库策略和CollectTimeYYYYMMDDTBShardingAlgorithm分表策略

这两个分别实现的是MultipleKeysDatabaseShardingAlgorithm实现了dosharding方法

CollectTimeYYYYMMDDTBShardingAlgorithm实现了SingleKeyTableShardingAlgorithm中的

 doEqualSharding ，doInSharding ， doBetweenSharding三个方法分别匹配sql语句中的 = , in , between

具体的实现就不写了，因为分片策略不同的场景有着不同的策略，理解了自然就通了。

综合以上讲解：实现sharding-jdbc数据源可以分为以下流程

一、写好配置文件

    ①包括制定数据源的类，有可能是自己实现的数据源

public class SwitchableDruidDataSource extends DruidDataSource {private static final Logger log = LoggerFactory.getLogger(SwitchableDruidDataSource.class);private static int maxRetryTimes = 20;private static int retryInterval = 10 * 1000;@Overridepublic Connection createPhysicalConnection() throws SQLException {if (!Boolean.valueOf(EmpfLocalConfigure.getValue("jdbc.ssl.switchable"))) {return super.createPhysicalConnection();}int retryCounter = 0;while (retryCounter < maxRetryTimes) {try {return super.createPhysicalConnection();} catch (Exception ex) {log.error("createPhysicalConnection error, ", ex);try {Thread.sleep(retryInterval);} catch (InterruptedException e1) {e1.printStackTrace();LoggerFactory.getLogger(DruidDataSource.class).info("retry with url[{}] => ", retryCounter, this.getUrl());}retryCounter++;switchSSL();if (retryCounter >= maxRetryTimes) {return super.createPhysicalConnection();}}}return null;}private void switchSSL() {if (StringUtils.indexOf(getUrl(), "useSSL=true") != -1) {this.setUrl(StringUtils.replace(getUrl(), "useSSL=true", "useSSL=false"));this.setUrl(StringUtils.replace(getUrl(), "verifyServerCertificate=true", "verifyServerCertificate=false"));} else if (StringUtils.indexOf(getUrl(), "useSSL=false") != -1) {this.setUrl(StringUtils.replace(getUrl(), "useSSL=false", "useSSL=true"));this.setUrl(StringUtils.replace(getUrl(), "verifyServerCertificate=false", "verifyServerCertificate=true"));}}}

     ②写好数据源和逻辑表的分库分表策略：这个可参考前两篇文章

     二，写sharding 数据源，这个数据源要继承dangdang的shardingdatasource

public class YamlShardingDataSource extends com.dangdang.ddframe.rdb.sharding.jdbc.ShardingDataSource {private YamlConfig yamlConfig = null;public YamlShardingDataSource(final File yamlFile) throws IOException {// C_387386 NULL_RETURNSsuper(new ShardingRuleBuilder(yamlFile.getName(), unmarshal(yamlFile)).build(), null != unmarshal(yamlFile) ? unmarshal(yamlFile).getProps() : null);yamlConfig = unmarshal(yamlFile);LoggerFactory.getLogger(YamlShardingDataSource.class).debug("debug ==> " + yamlFile.getCanonicalPath());}private static YamlConfig unmarshal(final File yamlFile) throws IOException {try (FileInputStream fileInputStream = new FileInputStream(yamlFile);InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8")) {return new Yaml(new YamlShardingConstructor()).loadAs(inputStreamReader, YamlConfig.class);}}public YamlConfig getYamlConfig() {return yamlConfig;}
}

 其中YamlShardingConstructor：

package com.pinnet.sharding.datasource;import com.pinnet.platformmon.configure.EmpfLocalConfigure;
import org.apachemons.lang.StringUtils;
import org.yaml.snakeyaml.constructor.Constructor;
import org.yaml.snakeyaml.nodes.Node;
import org.yaml.snakeyaml.nodes.NodeId;
import org.yaml.snakeyaml.nodes.ScalarNode;
import java.util.regex.Matcher;
import java.util.regex.Pattern;public class YamlShardingConstructor extends Constructor {//yaml规范已有${}，此处使用${{}}做标记private static final Pattern placeHolderPattern = Patternpile("\\$\\{\\{([^}}]+)\\}\\}");public YamlShardingConstructor() {super(YamlConfig.class);yamlClassConstructors.put(NodeId.scalar, new EncryptedConstructScalar());}/*** YAML解析插入自定义逻辑*/private class EncryptedConstructScalar extends ConstructScalar {public Object construct(Node node) {if (node instanceof ScalarNode) {String val = (String) constructScalar((ScalarNode) node);//【安全特性简述】如果yaml中有${{}}，则用EmpfLocalConfigure中的值替换Matcher matcher = placeHolderPattern.matcher(val);boolean replace = false;while (matcher.find()) {replace = true;val = StringUtils.replace(val, matcher.group(0), EmpfLocalConfigure.getValue(matcher.group(1)));}if (replace) {return val;}}return super.construct(node);}}}

 yamlconifg

public class YamlConfig extends ShardingRuleConfig {private Properties props = new Properties();public Properties getProps() {return props;}public void setProps(Properties props) {this.props = props;}
}

分片策略详解可以查看：

本文标签： sharding