spring boot+mybatis 多数据源切换

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@EnableSchedulingpublic class DataSourceConfig {/*@Autowiredprivate 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;}@Beanpublic 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;@Beanpublic 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    */@Beanpublic 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@Overrideprotected 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();}}

5.就是使用aop，在dao层切换数据源

@Component@Aspectpublic 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。