spring boot+mybatis 多数据源切换(实例讲解)

由于公司业务划分了多个数据库，开发一个项目会同事调用多个库，经过学习我们采用了注解+aop的方式实现的

1.首先定义一个注解类

@retention(retentionpolicy.runtime)
@target(elementtype.method)
public @interface targetdatasource {
 string value();//此处接收的是数据源的名称
}

2.然后建一个配置类，这个在项目启动时会加载数据源，一开始采用了hikaricp，查资料说是最快性能最好的，然后又发现了阿里的druid，这个功能比较全面，而且性能也还可以，最主要他还有监控功能，具体实现看如下代码

package com.example.demo.datasource;

import com.alibaba.druid.pool.druiddatasource;
import com.alibaba.druid.support.http.statviewservlet;
import com.alibaba.druid.support.http.webstatfilter;
import com.example.demo.datasource.dynamicdatasource;
import com.zaxxer.hikari.hikariconfig;
import com.zaxxer.hikari.hikaridatasource;
import lombok.extern.slf4j.slf4j;
import org.mybatis.spring.annotation.mapperscan;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.beans.factory.annotation.qualifier;
import org.springframework.beans.factory.annotation.value;
import org.springframework.boot.web.servlet.filterregistrationbean;
import org.springframework.boot.web.servlet.servletregistrationbean;
import org.springframework.context.annotation.bean;
import org.springframework.context.annotation.configuration;
import org.springframework.jdbc.datasource.datasourcetransactionmanager;
import org.springframework.scheduling.annotation.enablescheduling;
import org.springframework.scheduling.annotation.scheduled;
import org.springframework.transaction.platformtransactionmanager;
import org.w3c.dom.nodelist;
import org.w3c.dom.document;
import org.w3c.dom.element;
import org.w3c.dom.node;

import javax.servlet.annotation.webinitparam;
import javax.servlet.annotation.webservlet;
import javax.sql.datasource;
import javax.xml.parsers.documentbuilder;
import javax.xml.parsers.documentbuilderfactory;
import java.lang.reflect.field;
import java.lang.reflect.method;
import java.util.hashmap;
import java.util.map;
import java.io.file;
import com.alibaba.druid.support.http.statviewservlet;
/**
 * author: wangchao
 * version：
 * date:  2017/9/11
 * description:数据源配置
 * modification history:
 * date    author    version   description
 * --------------------------------------------------------------
 * why & what is modified:
 */

@configuration
@enablescheduling
public class datasourceconfig {

 /*@autowired
 private dbproperties properties;*/
 @value("${datasource.filepath}")
 private string filepath;//数据源配置

 @bean(name = "datasource")
 public datasource datasource() {
  //按照目标数据源名称和目标数据源对象的映射存放在map中
  map<object, object> targetdatasources = new hashmap<>();
  //查找xml数据连接字符串
  targetdatasources=getdatamap(filepath);
  //动态获取dbproperties类申明的属性
  /*field[] fields=properties.getclass().getdeclaredfields();
  for(int i=0;i<fields.length;i++)
  {
   targetdatasources.put(fields[i].getname(), getfieldvaluebyname(fields[i].getname(),properties));
  }*/
  //采用是想abstractroutingdatasource的对象包装多数据源
  dynamicdatasource datasource = new dynamicdatasource();
  datasource.settargetdatasources(targetdatasources);
  //设置默认的数据源，当拿不到数据源时，使用此配置
  //datasource.setdefaulttargetdatasource(properties.getuzaitravel());
  return datasource;
 }

 @bean
 public platformtransactionmanager txmanager() {
  return new datasourcetransactionmanager(datasource());
 }

 /**
 *获取数据源集合
 */

 private map<object, object> getdatamap(string fiepath)
 {

  try {
   map<object, object> targetdatasources = new hashmap<>();
   file xmlfile = new file(fiepath);

   documentbuilderfactory builderfactory = documentbuilderfactory.newinstance();

   documentbuilder builder = builderfactory.newdocumentbuilder();

   document doc = builder.parse(xmlfile);

   doc.getdocumentelement().normalize();

   system.out.println("root element: " + doc.getdocumentelement().getnodename());

   nodelist nlist = doc.getelementsbytagname("db");
   for(int i = 0 ; i<nlist.getlength();i++) {

    node node = nlist.item(i);
    element ele = (element)node;

    /*hikariconfig config = new hikariconfig();
    config.setdriverclassname(ele.getelementsbytagname("driver-class").item(0).gettextcontent());
    config.setjdbcurl(ele.getelementsbytagname("jdbc-url").item(0).gettextcontent());
    config.setusername(ele.getelementsbytagname("username").item(0).gettextcontent());
    config.setpassword(ele.getelementsbytagname("password").item(0).gettextcontent());
    //config.adddatasourceproperty("password", ele.getelementsbytagname("password").item(0).gettextcontent());
    hikaridatasource datasource = new hikaridatasource(config);*/


    druiddatasource datasource = new druiddatasource();
    datasource.setdriverclassname(ele.getelementsbytagname("driver-class").item(0).gettextcontent());
    datasource.setusername(ele.getelementsbytagname("username").item(0).gettextcontent());
    datasource.setpassword(ele.getelementsbytagname("password").item(0).gettextcontent());
    datasource.seturl(ele.getelementsbytagname("jdbc-url").item(0).gettextcontent());
    datasource.setinitialsize(5);
    datasource.setminidle(1);
    datasource.setmaxactive(10);// 启用监控统计功能
    datasource.setfilters("stat");//设置是否显示sql语句
    targetdatasources.put(ele.getelementsbytagname("databasename").item(0).gettextcontent(), datasource);
   }
   return targetdatasources;
  }
  catch (exception ex)
  {
   return null;
  }

 }
 //访问的ip
 @value("${druid.ip}")
 private string ip;
 //登录名
 @value("${druid.druidlgoinname}")
 private string druidlgoinname;
 //密码
 @value("${druid.druidlgoinpassword}")
 private string druidlgoinpassword;

 @bean
 public servletregistrationbean druidstatviewservle() {
  //org.springframework.boot.context.embedded.servletregistrationbean提供类的进行注册.
  servletregistrationbean servletregistrationbean = new servletregistrationbean(new statviewservlet(), "/druid/*");
  //添加初始化参数：initparams

  //白名单：
  servletregistrationbean.addinitparameter("allow",ip);
  //ip黑名单 (存在共同时，deny优先于allow) : 如果满足deny的话提示:sorry, you are not permitted to view this page.
  // servletregistrationbean.addinitparameter("deny", "192.168.1.73");
  //登录查看信息的账号密码.
  servletregistrationbean.addinitparameter("loginusername",druidlgoinname);
  servletregistrationbean.addinitparameter("loginpassword",druidlgoinpassword);
  //是否能够重置数据.
  servletregistrationbean.addinitparameter("resetenable","false");
  return servletregistrationbean;
 }

 /**

  * 注册一个：filterregistrationbean

  * @return

 */
 @bean
 public filterregistrationbean druidstatfilter2(){
  filterregistrationbean filterregistrationbean = new filterregistrationbean(new webstatfilter());
  //添加过滤规则.
  filterregistrationbean.addurlpatterns("/*");
  //添加不需要忽略的格式信息.
  filterregistrationbean.addinitparameter("exclusions","*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
  return filterregistrationbean;
 }

}

3.动态数据源，从之前已加载的数据源中选取，dynamicdatasource和dynamicdatasourceholder配合使用

public class dynamicdatasource extends abstractroutingdatasource{
 //数据源路由，此方用于产生要选取的数据源逻辑名称
 @override
 protected object determinecurrentlookupkey() {
  //从共享线程中获取数据源名称
  return dynamicdatasourceholder.getdatasource();
 }
}

public class dynamicdatasourceholder {
 /**
  * 本地线程共享对象
  */
 private static final threadlocal<string> thread_local = new threadlocal<>();

 public static void putdatasource(string name) {
  thread_local.set(name);
 }

 public static string getdatasource() {
  return thread_local.get();
 }

 public static void removedatasource() {
  thread_local.remove();
 }
}

4.就是使用aop，在dao层切换数据源

@component
@aspect
public class datasourceaspect {
 //切换放在mapper接口的方法上，所以这里要配置aop切面的切入点
 @pointcut("execution( * com.example.demo.dao.*.*(..))")
 public void datasourcepointcut() {
 }

 @before("datasourcepointcut()")
 public void before(joinpoint joinpoint) {
  object target = joinpoint.gettarget();
  string method = joinpoint.getsignature().getname();
  class<?>[] clazz = target.getclass().getinterfaces();
  class<?>[] parametertypes = ((methodsignature) joinpoint.getsignature()).getmethod().getparametertypes();
  try {
   method m = clazz[0].getmethod(method, parametertypes);
   //如果方法上存在切换数据源的注解，则根据注解内容进行数据源切换
   if (m != null && m.isannotationpresent(targetdatasource.class)) {
    targetdatasource data = m.getannotation(targetdatasource.class);
    string datasourcename = data.value();
    dynamicdatasourceholder.putdatasource(datasourcename);

   } else {

   }
  } catch (exception e) {

  }
 }

 //执行完切面后，将线程共享中的数据源名称清空
 @after("datasourcepointcut()")
 public void after(joinpoint joinpoint){
  dynamicdatasourceholder.removedatasource();
 }
}

数据连接都配置在xml里面

xml路径在配置文件里面配置，这样适用读写分离和多个不同的数据源，而且多个项目可以共用这一个配置

最后引用注解，需要注意的是注解的数据库名称和xml里面databasename节点是一一对应的，可以随便自定义，比如读写是一个数据库名字，这时候就可以定义成pringtest_r表示读库

至此多数据源就配置完成，至于阿里的druid下次再分享，代码都贴出来，如果大家感觉还有哪些不足的地方，欢迎指正。

以上这篇spring boot+mybatis 多数据源切换(实例讲解)就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持服务器之家。

原文链接：http://www.cnblogs.com/ok123/archive/2017/09/14/7523106.html