Spring PropertySource返回空

Question

你好，我目前正在获取.properties文件的值。我遇到了一个问题。我用的是春靴。见下面我的样本来源；

Browser.java

@Controller
public class Browser {

    @Autowired
    private BrowserConfiguration conf;

    public Browser(){
        System.out.println("I am initializing...");
        System.out.println("Reading configuration files..."+conf);
        System.out.println("Starting selected browser...");
        System.out.println("Waiting for command execution...");
    }

}

BrowserConfiguration.java

@Configuration
@PropertySource("file:./properties/test-config.properties")
public class BrowserConfiguration {

    @Value( "${browser.target}" )
    private String browser;

    public String getBrowser() {
        return browser;
    }

    public void setBrowser(String browser) {
        this.browser = browser;
    }

    @Override
    public String toString(){
        return "Target Browser: "+getBrowser();
    }

}

Demo1Application.java

@SpringBootApplication
public class DemoApplication implements CommandLineRunner  {

    @Autowired
    private Browser browser;

    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(DemoApplication.class);
        app.setBannerMode(Mode.OFF);
        app.run(args);
    }

    @Override
    public void run(String... arg0) throws Exception {
        // TODO Auto-generated method stub
        browser.runTest("test1");
    }
}

test-config.properties

browser.target=ie

控制台记录

2017-04-29 23:51:10.537  INFO 6912 --- [           main] com.example.Demo1Application             : Starting Demo1Application on Mikram-PC with PID 6912 (C:\Users\Mikram\sts-workspace\demo-1\target\classes started by Mikram in C:\Users\Mikram\sts-workspace\demo-1)
2017-04-29 23:51:10.540  INFO 6912 --- [           main] com.example.Demo1Application             : No active profile set, falling back to default profiles: default
2017-04-29 23:51:10.576  INFO 6912 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@67b467e9: startup date [Sat Apr 29 23:51:10 SGT 2017]; root of context hierarchy
I am initializing...
Reading configuration files...null
Starting selected browser...
Waiting for command execution...
2017-04-29 23:51:11.051  INFO 6912 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
I am search now!
2017-04-29 23:51:11.062  INFO 6912 --- [           main] com.example.Demo1Application             : Started Demo1Application in 0.722 seconds (JVM running for 1.02)
2017-04-29 23:51:11.063  INFO 6912 --- [       Thread-2] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@67b467e9: startup date [Sat Apr 29 23:51:10 SGT 2017]; root of context hierarchy
2017-04-29 23:51:11.064  INFO 6912 --- [       Thread-2] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown

问题：

我似乎无法在浏览器类中连接BrowserConfiguration。我错过了什么吗？请给我指明正确的方向。我现在迷路了。

Answer 1

您正在使用字段注入，但是访问构造函数中的变量。因为在创建对象时调用了构造函数，Spring还没有机会设置变量。在这种情况下，您必须使用基于构造函数的注入：

@Autowired
public Browser(BrowserConfiguration conf) {
    this.conf = conf;

    //Use the variable here
}