java - J'ai configuré une source de données, pourquoi est-il demandé qu'il y ait plus d'un bean de type "DataSource"?

Question

Il semble que je n'ai configuré qu'une seule source de données. Pourquoi est-il demandé qu'il existe plusieurs sources de données lors de l'injection ?

package com.example.demo.config;

import org.apache.commons.dbcp.BasicDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

@Configuration
@PropertySource("classpath:application.properties")
public class DataSourceConfiguration {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;
    @Value("${jdbc.maxActive}")
    private int maxActive;
    @Value("${jdbc.maxIdel}")
    private int maxIdel;
    @Value("${jdbc.maxWait}")
    private long maxWait;

    @Bean
    //应该就这一个吧
    public BasicDataSource dataSource(){
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName(driver);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        dataSource.setMaxActive(maxActive);
        dataSource.setMaxIdle(maxIdel);
        dataSource.setMaxWait(maxWait);
        dataSource.setValidationQuery("SELECT 1");
        dataSource.setTestOnBorrow(true);
        return dataSource;
    }
}

package com.example.demo.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;

import javax.annotation.Resource;
import javax.annotation.Resources;
import javax.sql.DataSource;


@Configuration
@EnableTransactionManagement
public class MyBatisConfig implements TransactionManagementConfigurer {

    @Autowired
    //这里怎么不能用@Autowired，用Resource倒是可以
    private DataSource dataSource;

    @Override
    public PlatformTransactionManager annotationDrivenTransactionManager() {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactoryBean() {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);

        try {
            return bean.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

Answer 1

Exécutez-le et voyez le message d'erreur