Spring XML相当于@Primary

Question

是否有与 @Primary 等效的XML
，可以提升多个合格Bean之一

示例场景：

我有一个启用了自动配置功能的spring-boot应用程序。我已经定义了多个数据源，但是spring无法选择其中一个数据源作为其默认值。

org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [javax.sql.DataSource] is defined: expected single matching bean but found 2: mysqlDataSource,oracleDataSource

datasources.xml

 <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/jdbc
        http://www.springframework.org/schema/jdbc/spring-jdbc.xsd">

    <bean id="mysqlDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/mcs" />
        <property name="username" value="root" />
        <property name="password" value="root" />
    </bean>


    <bean id="oracleDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@localhost:1521:test" />
        <property name="username" value="scott" />
        <property name="password" value="tiger" />
    </bean>

    <bean id="transactionManager"
    class="org.springframework.batch.support.transaction.ResourcelessTransactionManager" />

</beans>

Answer 1

<bean>属性具有primary属性：

<bean primary="true|false"/>

并记住：

如果@Primary通过XML声明了-annotated类，则@Primary注释元数据将被忽略，<bean primary="true|false"/>而是被尊重。