SpringBoot整合JDBC数据库操作第九弹-配置多DataSource/Transactional

上篇文章我们讲到了使用代码注入DataSource,这篇文章主要讲解一下在项目中配置多DataSource和启用Transactional事务.

• 将application.yml配置文件加入以下内容

  custom-second:
    source:
      driver: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test1
      username: root
      password: 123456
  

• 在源码目录下新建config目录, 在该目录下新建CustomSecondDataSource类文件

  /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * 
  
   * http://www.apache.org/licenses/LICENSE-2.0
   * 
  
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.edurt.config;
   
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
  import org.springframework.boot.context.properties.ConfigurationProperties;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.jdbc.core.JdbcTemplate;
   
  import javax.sql.DataSource;
   
  /**
   * CustomSecondDataSource 
  
   * 描述 : CustomSecondDataSource 
  
   * 作者 : qianmoQ 
  
   * 版本 : 1.0 
  
   * 创建时间 : 2018-03-29 下午1:29 
  
   * 联系作者 : qianmoQ
   */
  @Configuration
  public class CustomSecondDataSource {
   
      @Bean(name = "secondDatasource")
      @ConfigurationProperties(prefix = "custom-second.source")
      public DataSource secondDataSource() {
          return DataSourceBuilder.create().build();
      }
   
      @Bean(name = "secondJdbcTemplate")
      public JdbcTemplate secondJdbcTemplate(@Qualifier("secondDatasource") DataSource dataSource) {
          return new JdbcTemplate(dataSource);
      }
   
  }
  

注意secondJdbcTemplate在创建时，传入的DataSource必须用@Qualifier("secondDatasource")声明，这样，才能使用第二个DataSource。

• 将CustomDataSource文件中的dataSource和jdbcTemplate标记为主要的, 修改为以下内容

  @Bean
  @Primary
  public DataSource dataSource() {
      return DataSourceBuilder.create()
              .driverClassName(driver)
              .url(url)
              .username(username)
              .password(password).build();
  }
   
  @Bean
  @Primary
  public JdbcTemplate jdbcTemplate() {
      return new JdbcTemplate(dataSource());
  }
  

• 在repository文件夹下创建SecondRepository用于测试第二个datasource

  /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * 
  
   * http://www.apache.org/licenses/LICENSE-2.0
   * 
  
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.edurt.repository;
   
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.jdbc.core.JdbcTemplate;
  import org.springframework.stereotype.Component;
   
  /**
   * SecondRepository 
  
   * 描述 : SecondRepository 
  
   * 作者 : qianmoQ 
  
   * 版本 : 1.0 
  
   * 创建时间 : 2018-03-29 下午1:35 
  
   * 联系作者 : qianmoQ
   */
  @Component
  public class SecondRepository {
   
      @Autowired
      @Qualifier("secondJdbcTemplate")
      // 在需要使用第二个JdbcTemplate的地方，我们注入时需要用@Qualifier("secondJdbcTemplate")标识
      private JdbcTemplate jdbcTemplate;
   
      public int save(int i) {
          return jdbcTemplate.update("INSERT INTO a(id) VALUES (?)", i);
      }
   
  }
  

• 修改ArticleController对外接口类

  @Autowired
  private SecondRepository secondRepository;
   
  @RequestMapping(value = "test", method = RequestMethod.POST)
  int test(@RequestParam Integer id) {
      return secondRepository.save(id);
  }
  

多个DataSource，多个JdbcTemplate时，强烈建议总是使用@Primary把其中某一个Bean标识为“主要的”，使用@Autowired注入时会首先使用被标记为@Primary的Bean

• 启用Transactional的话我们只需要将@EnableTransactionManagement增加到项目的启动类中和将@Transactional注解增加到我们要做事务的方法上即可