jdbc:
  url: jdbc:mysql://localhost:3306/blogdb?useUnicode=true&characterEncoding=utf-8

@Service
public class JDBCService {
	@Value('@{jdbc.url}') // spel 表达式
	private String  url ; 

	public String getJDBCUrl() {
		return this.url;
	}
}


@RestController
public class JDBCController{
	@Autowired
	private JDBCService jdbcService ; 
	
	@RequestMapping("/jdbcUrl") 
	public String jdbcUrl() {
		return jdbcService.getJDBCUrl();
	}
}

手写，没验证，反正大概就这样