在使用@Value注释注入类的字段和使用Spring Environment API查找它们之间是否有显着差异？一个比另一个更可取（在什么情况下）？

使用@Value的示例：

class Config {
    @Value("${db.driverClassName}")
    private String driverClassName;

    @Value("${db.url}")
    private String url;

    @Value("${db.username}")
    private String username;

    @Value("${db.password}")
    private String password;

    @Bean
    public javax.sql.DataSource dataSource(){

        PoolProperties poolProperties = new PoolProperties();
        poolProperties.setDriverClassName(driverClassName);
        poolProperties.setUrl(url);         
        poolProperties.setUsername(username);
        poolProperties.setPassword(password);

        return new org.apache.tomcat.jdbc.pool.DataSource(poolProperties);

    }

}

使用环境API的示例：

class Config {
    @Autowired
    private Environment environment;

    @Bean
    public javax.sql.DataSource dataSource(){

        PoolProperties poolProperties = new PoolProperties();
        poolProperties.setDriverClassName(environment.getProperty("db.driverClassName"));
        poolProperties.setUrl(environment.getProperty("db.url"));           
        poolProperties.setUsername(environment.getProperty("db.username"));
        poolProperties.setPassword(environment.getProperty("db.password"));

        return new org.apache.tomcat.jdbc.pool.DataSource(poolProperties);
    }

}