SpringBoot学习:Jdbc链接数据库

一时失言乱红尘 2022-05-30 01:49 179阅读 0赞

仅为记录自己学习过程

前置条件:

假设已有一个MySQL数据库,其中创建一个table叫做people ,有id,name...列.

### 引入依赖： ###

在pom文件引入spring-boot-starter-jdbc的依赖：

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

引入mysql连接类和连接池：

<dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.0.29</version>
            </dependency>

开启web:

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>

### 配置相关文件 ###

在jdbc.properties文件配置mysql的驱动类，数据库地址，数据库账号、密码信息。

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/people
    spring.datasource.username=root
    spring.datasource.password=root

**修改Application.java**

/**
     * Created by Administrator on 2018/3/1.
     */
    @SpringBootApplication
    public class Application {
        public  static void  main(String[] args){
            SpringApplication.run(Application.class,args);
    
            @Autowired
             private Environment env;//获取配置文件的一种方式
            //destroy-method="close"的作用是当数据库连接不使用的时候,就把该连接重新放到数据池中,方便下次使用调用.
            @Bean(destroyMethod = "close")
            public DataSource dataSource(){
                DruidDataSource dataSource =new DruidDataSource();
                dataSource.setUrl(env.getProperty("spring.datasource.url"));
                dataSource.setUsername(env.getProperty("spring.datasource.username"));
                dataSource.setPassword(env.getProperty("spring.datasource.password"));
                dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
                dataSource.setInitialSize(2);//初始化时建立物理连接的个数
                dataSource.setMaxActive(20);//最大连接池数量
                dataSource.setMinIdle(0);//最小连接池数量
                dataSource.setMaxWait(60000);//最大等待时间,单位毫秒
                dataSource.setValidationQuery("SELECT 1");//用来检测连接是否有效
                dataSource.setTestOnBorrow(false);//申请连接时执行validationQuery检测连接是否有效
                dataSource.setTestWhileIdle(true);//建议配置为true，不影响性能，并且保证安全性。
                dataSource.setPoolPreparedStatements(false);//是否缓存preparedStatement，也就是PSCache
                return dataSource;
            }
        }

根据数据库创建一个实体类

/**
     * Created by Administrator on 2018/3/1.
     */
    public class People {
        private int id ;
        private String name ;
        ...
        //省略了setget
    }

控制层

@RestController
    @RequestMapping("/jdbc")
    public class PeopleController {
        @Autowired
        IJdbcService jdbcService;
    
        @RequestMapping(value = "/list",method = RequestMethod.GET)
        public List<People> getPeoples(){
            return  jdbcService.findPeopleList;
    
        }
    }

service层

@Service
    public class JdbcServiceImpl implements IJdbcService{
        @Autowired
        IJdbcDao iJdbcDao;
    
        @Override
        public List<People> findPeopleList(){
            return  iJdbcDao.findPeopleList();
        }

public interface IJdbcService {
        List<People> findPeopleList();
    }

Dao层

public interface IJdbcDao {
        List<People> findPeopleList();
    }

@Repository
    public class JdbcDaoImpl implements IJdbcDao {
        @Autowired
        private JdbcTemplate jdbcTemplate;
    
        @Override
        public List<People> findPeopleList(){
            List<People>list=jdbcTemplate.query("select * from table",new Object[]{},new BeanPropertyRowMapper(People.class));
            if(list!=null && list.size()>0){
                People people =list.get(0);
                return  people;
            }else {
                return  null;
            }
        }

参考:

http://blog.csdn.net/forezp/article/details/70477821\#reply

http://tengj.top/2017/04/13/springboot8/