SpringMVC4+MyBatis+SQL Server2014实现读写分离
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
<dependencies> <dependency> <groupId>junitgroupId> <artifactId>junitartifactId> <version>4.10version> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-coreartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-beansartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-contextartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-webartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-context-supportartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-webmvcartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-jdbcartifactId> <version>4.3.6.RELEASEversion> dependency> <dependency> <groupId>org.apache.velocitygroupId> <artifactId>velocityartifactId> <version>1.6.2version> dependency> <dependency> <groupId>org.apache.velocitygroupId> <artifactId>velocity-toolsartifactId> <version>2.0version> dependency> <dependency> <groupId>org.mybatisgroupId> <artifactId>mybatisartifactId> <version>3.4.2version> dependency> <dependency> <groupId>org.mybatisgroupId> <artifactId>mybatis-springartifactId> <version>1.3.0version> dependency> <dependency> <groupId>com.microsoft.sqlservergroupId> <artifactId>sqljdbc4artifactId> <version>4.0version> dependency> <dependency> <groupId>commons-dbcpgroupId> <artifactId>commons-dbcpartifactId> <version>1.4version> dependency> <dependency> <groupId>javax.servletgroupId> <artifactId>javax.servlet-apiartifactId> <version>3.1.0version> dependency> <dependency> <groupId>org.slf4jgroupId> <artifactId>slf4j-log4j12artifactId> <version>1.7.25version> dependency> dependencies>
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
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd "> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="locations" value="classpath:config/jdbc.properties"/> <property name="fileEncoding" value="UTF-8"/> bean> <bean id="abstractDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="${sqlserver.driver}"/> <property name="url" value="${sqlserver.url}"/> bean> <bean id="shawnTimeDataSourceRead" parent="abstractDataSource"> <property name="username" value="${sqlserver.read.username}"/> <property name="password" value="${sqlserver.read.password}"/> bean> <bean id="shawnTimeDataSourceWiter" parent="abstractDataSource"> <property name="username" value="${sqlserver.writer.username}"/> <property name="password" value="${sqlserver.writer.password}"/> bean> <bean id="shawnTimeDataSource" class="com.autohome.rwdb.DynamicDataSource"> <property name="readDataSource" ref="shawnTimeDataSourceRead"/> <property name="writeDataSource" ref="shawnTimeDataSourceRead"/> bean> <bean id="shawnTimeTransactionManager" class="com.autohome.rwdb.DynamicDataSourceTransactionManager"> <property name="dataSource" ref="shawnTimeDataSource"/> bean> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="configLocation" value="classpath:springmvc-mybatis.xml"/> <property name="dataSource" ref="shawnTimeDataSource"/> <property name="plugins"> <array> <bean class="com.autohome.rwdb.DynamicPlugin"/> array> property> bean> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.autohome.dao"/> bean> <mvc:annotation-driven/> <context:component-scan base-package="com.autohome.*"/> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/views/"/> <property name="suffix" value=".jsp"/> bean> beans>
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
参考
https://github.com/shawntime/shawn-rwdb
http://www.jianshu.com/p/2222257f96d3