How SpringBoot uses JdbcTemplate to operate the database

JdbcTemplate is a set of JDBC template framework provided by Spring, which uses AOP technology to solve the problem of a large amount of repeated code when using JDBC directly. Although not as flexible as MyBatis, it is much more convenient than using JDBC directly.

1. Create table

CREATE TABLE `t_demo` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(120) NOT NULL,
  `num` int(11) NOT NULL,
  `create_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT='demo表';

##2. Add dependencies and configuration

1. First edit the

pom.xml file and add relevant dependencies.

<!-- spring-jdbc -->
<dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-jdbc</artifactid>
</dependency>
 
<!-- 数据库驱动依赖 -->
<dependency>
    <groupid>mysql</groupid>
    <artifactid>mysql-connector-java</artifactid>
</dependency>
 
<!-- 数据库连接池 -->
<dependency>
    <groupid>com.alibaba</groupid>
    <artifactid>druid</artifactid>
    <version>1.1.9</version>
</dependency>

2. Write configuration

spring.datasource.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.url = jdbc:mysql://localhost:3306/PiaoDB?useUnicode=swater&characterEncoding=UTF-8
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.driver-class-name = com.mysql.jdbc.Driver

3. Write code

1. Write entity class

@Data
@Accessors(chain = true)
public class Demo {

    private Integer id;

    private String name;

    private Integer num;

    private Date createTime;

}

2. Write Dao Code

@Repository
public class DemoDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    // 新增数据
    public int addDemo(Demo demo) {
        return jdbcTemplate.update("INSERT INTO t_demo(name, num) VALUE (?, ?)",
                demo.getName(), demo.getNum());
    }

    // 修改数据
    public int updateDemo(Demo demo) {
        return jdbcTemplate.update("UPDATE t_demo SET name=?, num=? WHERE id=?",
                demo.getName(), demo.getNum(), demo.getId());
    }

    // 删除数据
    public int deleteDemoById(Integer id) {
        return jdbcTemplate.update("DELETE FROM t_demo WHERE id=?", id);
    }

    // 获取单条数据
    public Demo getDemoById(Integer id) {
        return jdbcTemplate.queryForObject("SELECT * FROM t_demo WHERE id=?",
                new BeanPropertyRowMapper(Demo.class), id);
    }

    // 获取多条数据
    public List<demo> getAllDemos() {
        return jdbcTemplate.query("SELECT * FROM t_demo",
                new BeanPropertyRowMapper(Demo.class));
    }

}</demo>

3. Write Controller code

@RestController
@RequestMapping("/demo")
public class DemoController {

    @Autowired
    private DemoDao demoDao;

    @RequestMapping("")
    public void test(){
        // 新增数据
        int num = demoDao.addDemo(new Demo().setName("piao").setNum(20));
        System.out.println("插入一条数据：" + num);

        // 修改数据
        int num2 = demoDao.updateDemo(new Demo().setId(15).setName("piao").setNum(22));
        System.out.println("更新一条数据：" + num2);

        // 删除数据
        int num3 = demoDao.deleteDemoById(13);
        System.out.println("删除一条数据：" + num3);

        // 查询单条数据
        Demo demo = demoDao.getDemoById(15);
        System.out.println("查询1条数据：" + demo.toString());

        // 查询多条数据
        List<demo> demos = demoDao.getAllDemos();
        System.out.println("查询多条数据：" + demos);
    }

}</demo>

4. Verification results

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