SSM框架,配置多个数据源

分手后的思念是犯贱 2022-03-24 18:42 251阅读 0赞

因为公司需求,不同的接口需要连接不同的数据库,在网上找了些资料,最后解决了这个问题

## 1.首先在db.properties里配置 ##

#dataSource1
    jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://XXX:3306/xxx?characterEncoding=utf-8&useSSL=false
    jdbc.username=root
    jdbc.password=root
    #dataSource2
    jdbc.driver2=com.mysql.jdbc.Driver
    jdbc.url2=jdbc:mysql://XXX:3306/xxx?characterEncoding=utf-8&useSSL=false
    jdbc.username2=root
    jdbc.password2=root

## 2.自定义注解 ##

package com.xxx.common;
    
    import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    
    @Target({
        ElementType.TYPE, ElementType.METHOD})
    @Retention(RetentionPolicy.RUNTIME)
    public @interface DataSource {
        
        String value();
    }

## 3.拦截解析注解类DataSourceAspect.java ##

package com.XXX.common;
    
    import org.aspectj.lang.JoinPoint;
    import org.aspectj.lang.reflect.MethodSignature;
    
    import java.lang.reflect.Method;
    
    
    public class DataSourceAspect{
        
        //	拦截目标方法，获取由@DataSource指定的数据源标识，设置到线程存储中以便切换数据源
        public void intercept(JoinPoint point) throws Exception{
        
            Class<?> target = point.getTarget().getClass();
            MethodSignature signature=(MethodSignature)point.getSignature();
            // 默认使用目标类型的注解，如果没有则使用其实现接口的注解
    
            for (Class<?> clazz : target.getInterfaces()) {
        
                resolveDataSource(clazz, signature.getMethod());
            }
            resolveDataSource(target, signature.getMethod());
        }
        /**
         * 提取目标对象方法注解和类型注解中的数据源标识
         */
    
        public void resolveDataSource(Class<?>clazz,Method method) {
        
            try {
        
                Class<?>[]types=method.getParameterTypes();
    //			默认使用类型注解
                if (clazz.isAnnotationPresent(DataSource.class)) {
        
                    DataSource source = clazz.getAnnotation(DataSource.class);
                    DbContextHolder.setDataSource(source.value());
                }
    //			方法注解可以覆盖类型注解
                Method m=clazz.getMethod(method.getName(), types);
                if (m!=null && m.isAnnotationPresent(DataSource.class)) {
        
                    DataSource source = m.getAnnotation(DataSource.class);
                    DbContextHolder.setDataSource(source.value());
                }
            } catch (Exception e) {
        
                System.out.println(clazz+":"+e.getMessage());
            }
        }
    }

## 4.切换数据库的工具类DbContextHolder.java ##

package com.xxx.common;
    
    
    public class DbContextHolder {
        
    	//ThreadLocal是一个本地线程副本变量工具类
        private static final ThreadLocal<String>THREAD_DATA_SOURCE =new ThreadLocal<String>();
        /**
         * 设置当前数据库
         */
        public static void setDataSource(String dataSource) {
        
            THREAD_DATA_SOURCE.set(dataSource);
        }
        /**
         * 取得当前数据库
         */
        public static String getDataSource() {
        
            return THREAD_DATA_SOURCE.get();
        }
    
        /**
         * 清除上下文数据
         */
        public static void clearDataSource() {
        
            THREAD_DATA_SOURCE.remove();
        }
    }

## 5.自定义动态数据源 ##

package com.xxx.common;
    
    import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
    
    public class MultipleDataSource extends AbstractRoutingDataSource {
        
        @Override
        protected Object determineCurrentLookupKey() {
        
            return  DbContextHolder.getDataSource();
        }
    }

## 6.配置dao.xml ##

<?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: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/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
    
    
        <context:property-placeholder location="classpath:properties/*.properties"/>
    
        <bean id="dataSource1" class="com.alibaba.druid.pool.DruidDataSource"
              destroy-method="close">
            <property name="url" value="${jdbc.url}"/>
            <property name="username" value="${jdbc.username}"/>
            <property name="password" value="${jdbc.password}"/>
            <property name="driverClassName" value="${jdbc.driver}"/>
            <property name="maxActive" value="10"/>
            <property name="minIdle" value="5"/>
        </bean>
        <bean id="dataSource2" class="com.alibaba.druid.pool.DruidDataSource"
              destroy-method="close">
            <property name="url" value="${jdbc.url2}"/>
            <property name="username" value="${jdbc.username2}"/>
            <property name="password" value="${jdbc.password2}"/>
            <property name="driverClassName" value="${jdbc.driver2}"/>
            <property name="maxActive" value="10"/>
            <property name="minIdle" value="5"/>
        </bean>
       <bean id="dataSource" class="com.xxx.xxx.MultipleDataSource">
            
            <property name="defaultTargetDataSource" ref="dataSource1"></property>
            <property name="targetDataSources">
                <map>
                    <entry key="dataSource1" value-ref="dataSource1"></entry>
                    <entry key="dataSource2" value-ref="dataSource2"></entry>
                </map>
            </property>
        </bean> 
        
        <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
        <bean id="dataSourceAspect" class="com.lyorcw.common.DataSourceAspect"></bean>
        <aop:config>
            <aop:aspect ref="dataSourceAspect">
                
                <aop:pointcut expression="execution(* com.lyorcw.resumesystem.mapper..*.*(..))" id="dataSourcePointcut"/>
                <aop:before method="intercept" pointcut-ref="dataSourcePointcut"/>
            </aop:aspect>
        </aop:config>
    
        <bean class="org.mybatis.spring.SqlSessionFactoryBean" id="sqlSessionFactory">
            <property name="dataSource" ref="dataSource"></property>
            <property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"></property>
            <property name="mapperLocations" value="classpath:/mapper/*.xml"/>
        </bean>
    
        <bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
            <property name="basePackage" value="com.lyorcw.resumesystem.mapper"/>
            <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
            <property name="properties">
                <value>
                    mappers=tk.mybatis.mapper.common.Mapper
                </value>
            </property>
        </bean>
    </beans>

## 7.只需要在dao层加上注解就行了 ##

package com.xxx.xxx.mapper;
    
    import com.xxx.xxx.DataSource;
    import com.xxx.xxx.user.AppResume;
    import org.apache.ibatis.annotations.Param;
    import tk.mybatis.mapper.common.Mapper;
    
    import java.util.List;
    
    public interface AppResumeMapper extends Mapper<AppResume>{
        
        @DataSource(value = "dataSource2")
    	AppResume lookResume(AppResume appResume);
    }

注解可以加在类上,也可以加在方法上面,方法级别覆盖类级别

## 8.总结: ##

**步骤:  
1.两个数据库分别配置不同id的DataSource  
2.配置切换数据库的自定义类的路径，选中默认数据库。  
3.配置aop拦截dao层的所有访问接口，在dao层注解更改数据库。**

不是原创,记录下来是为了以后用到了方法查看  
转载自:[https://blog.csdn.net/qq\_36746327/article/details/81033404][https_blog.csdn.net_qq_36746327_article_details_81033404]

[https_blog.csdn.net_qq_36746327_article_details_81033404]: https://blog.csdn.net/qq_36746327/article/details/81033404