你会用SpringBoot调用JDBC操作数据库么？

1 环境准备

数据库使用MySQL，我们先创建一个SpringBoot项目再导入MySQL驱动：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://192.168.137.140:3306/mysql
    driver-class-name: com.mysql.jdbc.Driver

2 测试代码

package cn.zhangyu;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

import static sun.misc.Version.println;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootJdbcApplicationTests {

    @Autowired
    DataSource dataSource;

    @Test
    public void contextLoads() throws SQLException {
    Connection connection = dataSource.getConnection();
    System.out.println(connection);
    connection.close();

    }

}

3 执行sql语句

DataSourceInitializer：ApplicationListener；可以帮助我们执行sql语句，但是需要将文件命名为：schema-.sql、data-.sql
默认规则：schema.sql，schema-all.sql；(DataSourceProperties这个类进行了默认的配置)

DataSourceInitializer作用：

1）、runSchemaScripts();运行建表语句；

2）、runDataScripts();运行插入数据的sql语句；

• 实例；

1. 再pom中添加

   #    如果你配置文件没有指定执行文件的名称而是使用默认的schema.sql或者schema-all.sql的话
   #    就在配置文件中加上spring.datasource.initialization-mode=always
      initialization-mode: always
   

2. 我们再resources目录下放入schema.sql

   SET FOREIGN_KEY_CHECKS=0;
   
   -- ----------------------------
   -- Table structure for department
   -- ----------------------------
   DROP TABLE IF EXISTS `department`;
   CREATE TABLE `department` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `departmentName` varchar(255) DEFAULT NULL,
    PRIMARY KEY (`id`)
   ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
   
   INSERT INTO department(id,departmentName) VALUES(1,'业务部');
   INSERT INTO department(id,departmentName) VALUES(2,'前台部');
   

3. 查看结果

   mysql> select * from department;
   +----+----------------+
   | id | departmentName |
   +----+----------------+
   |  1 | 业务部      |
   |  2 | 前台部      |
   +----+----------------+
   2 rows in set (0.00 sec)
   --------------------- 

4. 编写controller 进行测试

   package cn.zhangyu;
   
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.jdbc.core.JdbcTemplate;
   import org.springframework.web.bind.annotation.GetMapping;
   import org.springframework.web.bind.annotation.RestController;
   
   import java.util.List;
   import java.util.Map;
   
   /**
   * Created by grace on 2018/11/28.
   */
   @RestController
   public class HelloController {
   
      //spring boot中已经给我们注册好JdbcTemplate
      @Autowired
      JdbcTemplate jdbcTemplate;
   
      @GetMapping("/hello")
      public Map<String,Object> getDepartment(){
          List<Map<String, Object>> list = jdbcTemplate.queryForList("select * from department");
          return list.get(0);
      }
   }
   

访问http://localhost:8080/hello:
{"id":1,"departmentName":"业务部"}

• 自定义sql执行

#可以使用   
    schema:
      - classpath:department.sql

schema是一个list所以可以使用- 指定多个位置