Mybatis SQL拦截器实现

Mybatis SQL拦截器实现

主要功能:通过log4j配置mybatis的打印,只能输出到控制台,而并非真正能够实现sql的获取,本文主要通过拦截器实现sql的拦截,进而对sql进行相应的操作。

起因:因项目需要,服务器要配成双机热备,那么数据库(这里采用的是MySQL)也是双机的,这就牵涉到数据库同步的问题,由于某种原因(这就不透露了)不能采用MySQL自身的同步机制,采用原先C/S系统的同步机制进行同步。

实现方式:mybatis与主数据库正常交互,通过拦截器拦截sql并通过webservice将sql发送到C/S系统的同步模块,进而同步备数据库。

主要代码:

package com.shr.dao;

import java.text.DateFormat;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.Properties;

import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;

import javax.inject.Inject;
import javax.inject.Named;

import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.type.TypeHandlerRegistry;

@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 MyBatisSQLInterceptor implements Interceptor {
private Logger logger = Logger.getLogger(MyBatisSQLInterceptor.class.getSimpleName());

@SuppressWarnings("unused")
private Properties properties;

private ConcurrentLinkedDeque<String> list = new ConcurrentLinkedDeque<String>();
// @Inject
// @Named("soapClient")
// private SoapClient soapClient;

public MyBatisSQLInterceptor()
{
ExecutorService exec = Executors.newSingleThreadExecutor();
exec.execute(new Thread(){
public void run(){
while(true)
{
if(list.isEmpty() == false)
{
String sql = list.pollFirst();
logger.info("[SEND WS: ["+sql+"]]");
//与WebService交互
}
try {
TimeUnit.MILLISECONDS.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});

exec.shutdown();
}

public Object intercept(Invocation invocation) throws Throwable {
MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
Object parameter = null;
if (invocation.getArgs().length > 1) {
parameter = invocation.getArgs()[1];
}
BoundSql boundSql = mappedStatement.getBoundSql(parameter);
Configuration configuration = mappedStatement.getConfiguration();
Object returnValue = null;
returnValue = invocation.proceed();
showSql(configuration, boundSql);
return returnValue;
}

private String getParameterValue(Object obj) {
String value = null;
if (obj instanceof String) {
value = "'" + obj.toString() + "'";
} else if (obj instanceof Date) {
DateFormat formatter = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.CHINA);
value = "'" + formatter.format(obj) + "'";
// System.out.println(value);
} else {
if (obj != null) {
value = obj.toString();
} else {
value = "";
}

}
return value;
}

public String showSql(Configuration configuration, BoundSql boundSql) {
Object parameterObject = boundSql.getParameterObject();
List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
String sql = boundSql.getSql().replaceAll("[\\s]+", " ");
if (parameterMappings.size() > 0 && parameterObject != null) {
TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
sql = sql.replaceFirst("\\?", getParameterValue(parameterObject));

} else {
MetaObject metaObject = configuration.newMetaObject(parameterObject);
for (ParameterMapping parameterMapping : parameterMappings) {
String propertyName = parameterMapping.getProperty();
if (metaObject.hasGetter(propertyName)) {
Object obj = metaObject.getValue(propertyName);
sql = sql.replaceFirst("\\?", getParameterValue(obj));
} else if (boundSql.hasAdditionalParameter(propertyName)) {
Object obj = boundSql.getAdditionalParameter(propertyName);
sql = sql.replaceFirst("\\?", getParameterValue(obj));
}
}
}
}
logger.info(sql);
if(sql.startsWith("select") == false)
{
list.add(sql);
}
return sql;
}

public Object plugin(Object target) {
return Plugin.wrap(target, this);
}

public void setProperties(Properties properties0) {
this.properties = properties0;
}
}

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