spring boot 使用@ConfigurationProperties

有时候有这样子的情景，我们想把配置文件的信息，读取并自动封装成实体类，这样子，我们在代码里面使用就轻松方便多了，这时候，我们就可以使用@ConfigurationProperties，它可以把同类的配置信息自动封装成实体类

首先在配置文件里面，这些信息是这样子滴

connection.username=admin
connection.password=kyjufskifas2jsfs
connection.remoteAddress=192.168.1.1

这时候我们可以定义一个实体类在装载配置文件信息

@Component
@ConfigurationProperties(prefix="connection")
public class ConnectionSettings {

</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String username;
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String remoteAddress;
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String password ;

</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String getUsername() {
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> username;
}
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setUsername(String username) {
    </span><span style="color: #0000ff;">this</span>.username =<span style="color: #000000;"> username;
}
</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String getRemoteAddress() {
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> remoteAddress;
}
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setRemoteAddress(String remoteAddress) {
    </span><span style="color: #0000ff;">this</span>.remoteAddress =<span style="color: #000000;"> remoteAddress;
}
</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String getPassword() {
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> password;
}
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setPassword(String password) {
    </span><span style="color: #0000ff;">this</span>.password =<span style="color: #000000;"> password;
}

}

我们还可以把@ConfigurationProperties还可以直接定义在@bean的注解上，这是bean实体类就不用@Component和@ConfigurationProperties了

@SpringBootApplication
public class DemoApplication{

</span><span style="color: #008000;">//</span><span style="color: #008000;">...</span>

@Bean @ConfigurationProperties(prefix = "connection") public ConnectionSettings connectionSettings(){ return new ConnectionSettings();

}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> main(String[] args) {
    SpringApplication.run(DemoApplication.</span><span style="color: #0000ff;">class</span><span style="color: #000000;">, args);
}

}

然后我们需要使用的时候就直接这样子注入

@RestController
@RequestMapping("/task")
public class TaskController {

@Autowired ConnectionSettings conn;

@RequestMapping(value = {"/",""})

public String hellTask(){

String userName = conn.getUsername();

return "hello task !!";

}

}

如果发现@ConfigurationPropertie不生效，有可能是项目的目录结构问题，

你可以通过@EnableConfigurationProperties(ConnectionSettings.class)来明确指定需要用哪个实体类来装载配置信息

@Configuration
@EnableConfigurationProperties(ConnectionSettings.class)
 public class MailConfiguration { 
    @Autowired private MailProperties mailProperties;

@Bean </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> JavaMailSender javaMailSender() {
  </span><span style="color: #008000;">//</span><span style="color: #008000;"> omitted for readability</span>

}

}