SpringBoot 屬性注入 ConfigurationProperties

問題：ConfigurationProperties如何進行對象的賦值，
例， JdbcProperties中有 View對象，如何初始化View中的 prefix，suffix

ConfigurationProperties 的 Relaxed binding：鬆散綁定
不嚴格要求屬性文件中的屬性名與成員變量名一致。支持駝峯，中劃線，下劃線等等轉換，甚至支持對象引導。比如：user.friend.name：代表的是user對象中的friend屬性中的name屬性，顯然friend也是對象。

@ConfigurationProperties(prefix = "jdbc")
public class JdbcProperties {

    private String driverClassName;
    private String url;
    private String username;
    private String password;

    //配置文件以 jdbc.view 開頭
    private final View view = new View();

    public String getDriverClassName() {
        return driverClassName;
    }

    public void setDriverClassName(String driverClassName) {
        this.driverClassName = driverClassName;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public  View getView(){
        return this.view;
    }


    public static class View {

        /**
         * Spring MVC view prefix.
         */
        private String prefix;

        /**
         * Spring MVC view suffix.
         */
        private String suffix;

        public String getPrefix() {
            return this.prefix;
        }

        public void setPrefix(String prefix) {
            this.prefix = prefix;
        }

        public String getSuffix() {
            return this.suffix;
        }

        public void setSuffix(String suffix) {
            this.suffix = suffix;
        }

    }
}

application.properties
如果想要初始化View中的 prefix和suffix，則前綴應該爲 jdbc.view

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mytest?characterEncoding=utf-8
jdbc.username=ldmiao
jdbc.password=ldm1991

jdbc.view.prefix = qianzhui
jdbc.view.suffix = houzhui

測試：
在Controller中 使用@EnableConfigurationProperties(JdbcProperties.class)引入配置類
通過構造方法注入 JdbcProperties

@RequestMapping("springboot")
@Controller
@EnableConfigurationProperties(JdbcProperties.class)
public class HelloController {

    public HelloController(JdbcProperties jdbcProperties){
        System.out.println(jdbcProperties.getView().getPrefix());
    }

    @Autowired
    private DataSource dataSource;
   @GetMapping("show")
    public String test(){
        return "hello";
    }
}

debug啓動，啓動服務的時候就會執行構造方法