SpringMVC4+MyBatis+SQL Server2014实现数据库读写分离

前言

      基于mybatis的AbstractRoutingDataSource和Interceptor用拦截器的方式实现读写分离，根据MappedStatement的boundsql，查询sql的select、insert、update、delete，根据起判断使用读写连接串。

开发环境

    SpringMVC4、mybatis3

项目结构

读写分离实现

1、pom.xml

  
   junit
   junit
   4.10
  
  
   org.springframework
   spring-core
   4.3.6.RELEASE
  
  
   org.springframework
   spring-beans
   4.3.6.RELEASE
  
  
   org.springframework
   spring-context
   4.3.6.RELEASE
  
  
   org.springframework
   spring-web
   4.3.6.RELEASE
  
  
   org.springframework
   spring-context-support
   4.3.6.RELEASE
  
  
   org.springframework
   spring-webmvc
   4.3.6.RELEASE
  
  
   org.springframework
   spring-jdbc
   4.3.6.RELEASE
  
  
   org.apache.velocity
   velocity
   1.6.2
  
  
   org.apache.velocity
   velocity-tools
   2.0
  
  
   org.mybatis
   mybatis
   3.4.2
  
  
   org.mybatis
   mybatis-spring
   1.3.0
  
  
   com.microsoft.sqlserver
   sqljdbc4
   4.0
  
  
   commons-dbcp
   commons-dbcp
   1.4
  
  
   javax.servlet
   javax.servlet-api
   3.1.0
  
  
   org.slf4j
   slf4j-log4j12
   1.7.25
  
 

2、jdbc.properties

sqlserver.driver=com.microsoft.sqlserver.jdbc.SQLServerDriver
sqlserver.url=jdbc:sqlserver://127.0.0.1:1433;databaseName=test
sqlserver.read.username=sa
sqlserver.read.password=000000
sqlserver.writer.username=sa
sqlserver.writer.password=000000

3、springmvc-serlvet.xml，主要配置都在这里

4、DynamicDataSource。实现AbstractRoutingDataSource

package com.autohome.rwdb;
import java.util.HashMap;
import java.util.Map;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
public class DynamicDataSource extends AbstractRoutingDataSource {
  private Object writeDataSource; //写数据源
  private Object readDataSource; //读数据源
  @Override
  public void afterPropertiesSet() {
    if (this.writeDataSource == null) {
      throw new IllegalArgumentException("Property 'writeDataSource' is required");
    }
    setDefaultTargetDataSource(writeDataSource);
    Map targetDataSources = new HashMap();
    targetDataSources.put(DynamicDataSourceGlobal.WRITE.name(), writeDataSource);
    if(readDataSource != null) {
      targetDataSources.put(DynamicDataSourceGlobal.READ.name(), readDataSource);
    }
    setTargetDataSources(targetDataSources);
    super.afterPropertiesSet();
  }
  @Override
  protected Object determineCurrentLookupKey() {
    DynamicDataSourceGlobal dynamicDataSourceGlobal = DynamicDataSourceHolder.getDataSource();
    if(dynamicDataSourceGlobal == null
        || dynamicDataSourceGlobal == DynamicDataSourceGlobal.WRITE) {
      return DynamicDataSourceGlobal.WRITE.name();
    }
    return DynamicDataSourceGlobal.READ.name();
  }
  public void setWriteDataSource(Object writeDataSource) {
    this.writeDataSource = writeDataSource;
  }
  public Object getWriteDataSource() {
    return writeDataSource;
  }
  public Object getReadDataSource() {
    return readDataSource;
  }
  public void setReadDataSource(Object readDataSource) {
    this.readDataSource = readDataSource;
  }
}

5、DynamicDataSourceGlobal

package com.autohome.rwdb;
public enum DynamicDataSourceGlobal {
  READ, WRITE;
}

6、DynamicDataSourceHolder

package com.autohome.rwdb;
public final class DynamicDataSourceHolder {
  private static final ThreadLocal holder = new ThreadLocal();
  private DynamicDataSourceHolder() {
    //
  }
  public static void putDataSource(DynamicDataSourceGlobal dataSource){
    holder.set(dataSource);
  }
  public static DynamicDataSourceGlobal getDataSource(){
    return holder.get();
  }
  public static void clearDataSource() {
    holder.remove();
  }
}

7、DynamicDataSourceTransactionManager

package com.autohome.rwdb;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.TransactionDefinition;
public class DynamicDataSourceTransactionManager extends DataSourceTransactionManager {
  /**
   * 只读事务到读库，读写事务到写库
   * @param transaction
   * @param definition
   */
  @Override
  protected void doBegin(Object transaction, TransactionDefinition definition) {
    //设置数据源
    boolean readOnly = definition.isReadOnly();
    if(readOnly) {
      DynamicDataSourceHolder.putDataSource(DynamicDataSourceGlobal.READ);
    } else {
      DynamicDataSourceHolder.putDataSource(DynamicDataSourceGlobal.WRITE);
    }
    super.doBegin(transaction, definition);
  }
  /**
   * 清理本地线程的数据源
   * @param transaction
   */
  @Override
  protected void doCleanupAfterCompletion(Object transaction) {
    super.doCleanupAfterCompletion(transaction);
    DynamicDataSourceHolder.clearDataSource();
  }
}

8、DynamicPlugin

package com.autohome.rwdb;
import java.util.Locale;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.executor.keygen.SelectKeyGenerator;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.transaction.support.TransactionSynchronizationManager;
@Intercepts({
@Signature(type = Executor.class, method = "update", args = {
    MappedStatement.class, Object.class }),
@Signature(type = Executor.class, method = "query", args = {
    MappedStatement.class, Object.class, RowBounds.class,
    ResultHandler.class }) })
public class DynamicPlugin implements Interceptor {
  protected static final Logger logger = LoggerFactory.getLogger(DynamicPlugin.class);
  private static final String REGEX = ".*insert\\u0020.*|.*delete\\u0020.*|.*update\\u0020.*";
  private static final Map cacheMap = new ConcurrentHashMap();
  @Override
  public Object intercept(Invocation invocation) throws Throwable {
    boolean synchronizationActive = TransactionSynchronizationManager.isSynchronizationActive();
    if(!synchronizationActive) {
      Object[] objects = invocation.getArgs();
      MappedStatement ms = (MappedStatement) objects[0];
      DynamicDataSourceGlobal dynamicDataSourceGlobal = null;
      if((dynamicDataSourceGlobal = cacheMap.get(ms.getId())) == null) {
        //读方法
        if(ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {
          //!selectKey 为自增id查询主键(SELECT LAST_INSERT_ID() )方法，使用主库
          if(ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)) {
            dynamicDataSourceGlobal = DynamicDataSourceGlobal.WRITE;
          } else {
            BoundSql boundSql = ms.getSqlSource().getBoundSql(objects[1]);
            //获取MappedStatement 的sql语句，select update delete insert
            String sql = boundSql.getSql().toLowerCase(Locale.CHINA).replaceAll("[\\t\\n\\r]", " ");
            if(sql.matches(REGEX)) {
              dynamicDataSourceGlobal = DynamicDataSourceGlobal.WRITE;
            } else {
              dynamicDataSourceGlobal = DynamicDataSourceGlobal.READ;
            }
          }
        }else{
          dynamicDataSourceGlobal = DynamicDataSourceGlobal.WRITE;
        }
        System.out.println("设置方法["+ms.getId()+"] use ["+ dynamicDataSourceGlobal.name()+"] Strategy, SqlCommandType ["+ms.getSqlCommandType().name()+"]..");
        cacheMap.put(ms.getId(), dynamicDataSourceGlobal);
      }
      DynamicDataSourceHolder.putDataSource(dynamicDataSourceGlobal);
    }
    return invocation.proceed();
  }
  @Override
  public Object plugin(Object target) {
    if (target instanceof Executor) {
      return Plugin.wrap(target, this);
    } else {
      return target;
    }
  }
  @Override
  public void setProperties(Properties properties) {
  }
}　

测试分离是否实现

    运行UserController.index方法，然后从控制台看打印结果

以上所述是小编给大家介绍的SpringMVC4+MyBatis+SQL Server2014实现读写分离，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持！