本文记录下在springboot项目中使用jdbcTemplate访问数据库。
创建springboot项目，添加依赖，pom文件如下：
1 <!--web 依赖--> 2 <dependency> 3 <groupId>org.springframework.boot</groupId> 4 <artifactId>spring-boot-starter-web</artifactId> 5 </dependency> 6 <!--spring jdbc依赖--> 7 <dependency> 8 <groupId>org.springframework.boot</groupId> 9 <artifactId>spring-boot-starter-jdbc</artifactId> 10 </dependency> 11 <!--mysql 依赖--> 12 <dependency> 13 <groupId>mysql</groupId> 14 <artifactId>mysql-connector-java</artifactId> 15 </dependency> 16 17 <!-- fastjson --> 18 <dependency> 19 <groupId>com.alibaba</groupId> 20 <artifactId>fastjson</artifactId> 21 <version>1.2.47</version> 22 </dependency>
要访问数据库，我们必须配置数据库连接信息，application.properties中添加数据库链接信息。springboot中默认使用的是Hikari数据库连接池
1 #数据源配置 2 spring.datasource.url=jdbc:mysql://localhost:3306/test 3 spring.datasource.username=root 4 spring.datasource.password=123456 5 #驱动可以不配置，不配置时会从url中解析 6 spring.datasource.driver-class-name=com.mysql.jdbc.Driver
如果我们不想使用Hikari，比如想使用阿里的德鲁伊，我们可以修改
1 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
数据库创建表：
1 CREATE TABLE `t_city` ( 2 `id` BIGINT(11) NOT NULL AUTO_INCREMENT, 3 `cityName` VARCHAR(50) NOT NULL, 4 `cityCode` VARCHAR(50) NOT NULL, 5 PRIMARY KEY (`id`) 6 ) ENGINE=INNODB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8
创建与数据库表对应的实体类：
1 public class City {
2 private Long id;
3 private String cityName;
4 private String cityCode;
5
6 public City(){}
7
8 public City(String cityName, String cityCode){
9 this.cityName = cityName;
10 this.cityCode = cityCode;
11 }
12 //省略get和set方法
13 }
定义dao层接口及实现
1 public interface CityDAO {
2
3 int add(City city) throws Exception;
4
5 int delete(Long id) throws Exception;
6
7 int update(City city) throws Exception;
8
9 List<City> findAllCity() throws Exception;
10
11 City findById(Long id) throws Exception;
12
13 }
1 @Service("cityDAO")
2 public class CityDAOImpl implements CityDAO {
3
4 @Autowired
5 private JdbcTemplate jdbcTemplate;
6
7 @Override
8 public int add(City city) {
9 String sql = "insert into t_city (cityCode, cityName) values (?, ?)";
10 return jdbcTemplate.update(sql, city.getCityCode(), city.getCityName());
11 }
12
13 @Override
14 public int delete(Long id) {
15 String sql = "delete from t_city where id = ?";
16 return jdbcTemplate.update(sql, id);
17 }
18
19 @Override
20 public int update(City city) {
21 String sql = "update t_city set cityCode = ?, cityName = ? where id = ?";
22 return jdbcTemplate.update(sql, city.getCityCode(), city.getCityName(), city.getId());
23 }
24
25 @Override
26 public List<City> findAllCity() {
27 String sql = "select * from t_city";
28 return jdbcTemplate.query(sql, new Object[]{}, new BeanPropertyRowMapper(City.class));
29 }
30
31 @Override
32 public City findById(Long id) {
33 String sql = "select * from t_city where id = ?";
34 List<City> cityList = jdbcTemplate.query(sql, new Object[]{id}, new BeanPropertyRowMapper(City.class));
35 if(cityList != null && cityList.size()>0){
36 return cityList.get(0);
37 }
38 return null;
39 }
40 }
定义service层接口及实现
1 public interface CityService {
2
3 int add(City city) throws Exception;
4
5 int delete(Long id) throws Exception;
6
7 int update(City city) throws Exception;
8
9 List<City> findAllCity() throws Exception;
10
11 City findById(Long id) throws Exception;
12
13 }
1 @Service("cityService")
2 public class CityServiceImpl implements CityService {
3
4 @Autowired
5 private CityDAO cityDAO;
6
7 @Override
8 public int add(City city) throws Exception {
9 return cityDAO.add(city);
10 }
11
12 @Override
13 public int delete(Long id) throws Exception {
14 return cityDAO.delete(id);
15 }
16
17 @Override
18 public int update(City city) throws Exception {
19 return cityDAO.update(city);
20 }
21
22 @Override
23 public List<City> findAllCity() throws Exception {
24 return cityDAO.findAllCity();
25 }
26
27 @Override
28 public City findById(Long id) throws Exception {
29 return cityDAO.findById(id);
30 }
31 }
此处service和dao之间的代码看似可以省略一层，但是一般我们在dao层只做与数据库的交互，在service层处理相应的业务逻辑，所以还是需要做分层的。
为了看出代码执行效果，定义几个简单的restful api做测试。
controller代码如下
1 @RestController
2 @RequestMapping("/datas/city/jdbc")
3 public class CityController {
4
5 @Autowired
6 private CityService cityService;
7
8 @PutMapping
9 public String add(@RequestBody JSONObject jsonObject){
10 String cityCode = jsonObject.getString("cityCode");
11 String cityName = jsonObject.getString("cityName");
12 City city = new City(cityName, cityCode);
13 try {
14 cityService.add(city);
15 return "success";
16 } catch (Exception e) {
17 e.printStackTrace();
18 return "fail";
19 }
20 }
21
22 @DeleteMapping("/{id}")
23 public String delete(@PathVariable Long id){
24 try {
25 cityService.delete(id);
26 return "success";
27 } catch (Exception e) {
28 e.printStackTrace();
29 return "fail";
30 }
31 }
32
33 @PostMapping
34 public String update(@RequestBody JSONObject jsonObject){
35 Long id = jsonObject.getLong("id");
36 try {
37 City city = cityService.findById(id);
38 if(city != null){
39 String cityCode = jsonObject.getString("cityCode");
40 city.setCityCode(cityCode);
41 String cityName = jsonObject.getString("cityName");
42 city.setCityName(cityName);
43 cityService.update(city);
44 return "success";
45 }
46 } catch (Exception e) {
47 e.printStackTrace();
48 }
49 return "fail";
50 }
51
52 @GetMapping("/list")
53 public String list(){
54 try {
55 List<City> cityList = cityService.findAllCity();
56 return cityList.toString();
57 } catch (Exception e) {
58 e.printStackTrace();
59 }
60 return null;
61 }
62 }
如果我们不想使用springboot提供的默认配置信息，想要自己配置数据源信息也是可以的。自己配置就不需要在application.properties文件中配置datasource相关的信息了，我们可以创建自己的配置文件，在配置勒种读取并设置即可，
创建dbSource.properties
1 #datasource config 2 jdbc.driverClassName=com.mysql.jdbc.Driver 3 jdbc.url=jdbc:mysql://localhost:3306/test 4 jdbc.username=root 5 jdbc.password=123456
创建配置类
1 @Configuration
2 @PropertySource("classpath:dbSource.properties")
3 public class DataSourceConfig {
4
5 @Autowired
6 private Environment env;
7
8 @Bean
9 public JdbcTemplate jdbcTemplate(){
10 JdbcTemplate jdbcTemplate = new JdbcTemplate();
11 jdbcTemplate.setDataSource(dataSource());
12 return jdbcTemplate;
13 }
14
15 @Bean
16 public DataSource dataSource(){
17 System.out.println("初始化数据源start。。。");
18 //HikariDataSource dataSource = new HikariDataSource();
19 DruidDataSource dataSource = new DruidDataSource();
20 String driver = env.getProperty("jdbc.driverClassName").trim();
21 String url = env.getProperty("jdbc.url").trim();
22 String username = env.getProperty("jdbc.username").trim();
23 String password = env.getProperty("jdbc.password").trim();
24 dataSource.setDriverClassName(driver);
25 //dataSource.setJdbcUrl(url);//Hikar url
26 dataSource.setUrl(url);
27 dataSource.setUsername(username);
28 dataSource.setPassword(password);
29 System.out.println("初始化数据源end。。。");
30 return dataSource;
31 }
32
33 }
启动项目可以看到其中日志中如下
原文地址：https://www.cnblogs.com/wlzq/p/9669651.html
时间： 2024-08-30 02:34:11