Role: Used to specify the location of the properties file.
Attributes:
- value: Specifies the name and path of the file. Keywords: classpath, which means under the classpath.
Example ( based on @Import annotation in Spring ):
jdbcConfig.properties
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/springtest?serverTimezone=UTC
jdbc.username=root
jdbc.password=1234
JdbcConfig class:
package config;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;
import javax.sql.DataSource;
//和spring连接数据库相关的配置类
@Configuration
public class JdbcConfig {
@Value("${jdbc.driver}")
private String driver;
@Value("${jdbc.url}")
private String url;
@Value("${jdbc.username}")
private String username;
@Value("${jdbc.password}")
private String password;
//用于创建一个QueryRunner对象
@Bean(name = "runner")
@Scope(value = "prototype")
public QueryRunner createQueryRunner(DataSource dataSource) {
return new QueryRunner(dataSource);
}
//创建数据源对象
@Bean(name = "dataSource")
public DataSource createDataSource() {
try {
ComboPooledDataSource ds = new ComboPooledDataSource();
ds.setDriverClass(driver);
ds.setJdbcUrl(url);
ds.setUser(username);
ds.setPassword(password);
return ds;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
SpringConfiguration class:
package config;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.springframework.context.annotation.*;
import javax.sql.DataSource;
//该类是一个配置类,它的作用和bean.xml是一样的
@Configuration
@ComponentScan(basePackages = {"com.qublog","config"})
@Import(value = {JdbcConfig.class})
@PropertySources({
@PropertySource("classpath:jdbcConfig.properties")
})
public class SpringConfiguration {
}
AccountServiceTest class:
@Test
public void testFindAll() {
//获取容器
// ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfiguration.class);
//得到业务层对象
AccountService as = (AccountService) ac.getBean("accountService");
//执行方法
List<Account> accounts = as.findAllAccount();
for (Account account:accounts) {
System.out.println(account);
}
}