project.author=wpfc
project.create_time=2018/3/29

@Configuration
@ComponentScan("cn.edu.ntu")
@PropertySource("classpath:test.properties")
public class ElConfig {
?
?? ?@Value("#{systemProperties['os.name']}")
?? ?private String osName;
?? ?
?? ?//要想使用@Value 用${}占位符注入屬性，這個(gè)bean是必須的(PropertySourcesPlaceholderConfigurer)，
? ? //這個(gè)就是占位bean,
?? ?//另一種方式是不用value直接用Envirment變量直接getProperty('key') ?
?? ?@Value("${project.author}")
?? ?public String author;
? ??
?? ?@Autowired
?? ?private Environment environment;
?? ?
?? ?//You need this if you use @PropertySource + @Value
? ? @Bean
? ? public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
? ? ? ?return new PropertySourcesPlaceholderConfigurer();
? ? }
?? ?
?? ?public void printProperties(){
?? ??? ?System.out.println("os name : " + osName);
?? ??? ?System.out.println("author ?: " + author);
?? ??? ?System.out.println("env ? ? : " + environment.getProperty("project.create_time"));
?? ?}?? ?
}

public class MainApplication {
?? ?public static void main(String[] args){
?? ??? ?AnnotationConfigApplicationContext context = null;
?? ??? ?context = new AnnotationConfigApplicationContext(ElConfig.class);
?? ??? ?ElConfig bean = context.getBean(ElConfig.class);
?? ??? ?bean.printProperties();
?? ?}?? ?
}

? ? @Value("normal")
? ? private String normal; // normal (顯然這種注入的意義不大)

@Value("#{systemProperties['os.name']}")
? ? private String systemPropertiesName;?
//效果等同于 ?是因?yàn)閟pring模版把系統(tǒng)變量否放進(jìn)了Enviroment
@Value("${os.name}")
? ? private String systemPropertiesName;

@Value("#{ T(java.lang.Math).random() * 100.0 }")
? ? private double randomNumber; //41.29185128620939

? ? @Bean
? ? public Person person() {
? ? ? ? Person person = new Person();
? ? ? ? person.setName("fangshixiang");
? ? ? ? return person;
? ? }
?
//注入屬性
? ? @Value("#{person.name}")
? ? private String personName;
?
? ? @Test
? ? public void contextLoads() {
? ? ? ? System.out.println(personName); //fangshixiang
? ? }

? ? @Value("classpath:jdbc.properties")
? ? private Resource resourceFile; // 注入文件資源
?
? ? @Test
? ? public void contextLoads() throws IOException {
? ? ? ? System.out.println(resourceFile); //class path resource [jdbc.properties]
? ? ? ? String s = FileUtils.readFileToString(resourceFile.getFile(), StandardCharsets.UTF_8);
? ? ? ? System.out.println(s);
? ? ? ? //輸出：
? ? ? ? //db.username=fangshixiang
? ? ? ? //db.password=fang
? ? ? ? //db.url=jdbc:mysql://localhost:3306/mytest
? ? ? ? //db.driver-class-name=com.mysql.jdbc.Driver
? ? }

? ? @Value("http://www.baidu.com")
? ? private Resource testUrl; // 注入U(xiǎn)RL資源?
?
? ? @Test
? ? public void contextLoads() {
? ? ? ? System.out.println(testUrl); //URL [http://www.baidu.com]
? ? }

    @Value("#{person}")
    private Person value;
 
    @Test
    public void contextLoads() {
        System.out.println(value); //Person(name=fangshixiang, age=null, addr=null, hobby=null)
    }

    @Value("#{person.name}")
    private String personName;
 
    @Value("#{person.age}")
    private String perAge;
 
    //注入默認(rèn)值
    @Value("#{person.age?:20}")
    private String perAgeDefault;
 
    //如果age22這個(gè)key根本就不存在，啟動(dòng)肯定會(huì)報(bào)錯(cuò)的
    //@Value("#{person.age22?:20}")
    //private String perAgeDefault22;
 
    @Test
    public void contextLoads() {
        System.out.println(personName); //fangshixiang
        System.out.println(perAge); //null
        System.out.println(perAgeDefault); //20
    }

 
    @Value("#{person.parent.name}")
    private String parentName1;
 
    @Value("#{person['parent.name']}")
    private String parentName2;
 
    @Test
    public void contextLoads() {
        System.out.println(parentName1); //fangshixiang
        System.out.println(parentName2); //fangshixiang
    }

    @Value("#{'${os.name}' + '_' +  person.name}")
    private String age; 
 
    @Test
    public void contextLoads() {
        System.out.println(age); //Windows 10_fangshixiang
    }

@Configuration
@PropertySource("classpath:jdbc.properties")
public class PropertySourceConfig {
 
    @Value("${db.url}")
    private String dbUrl;
 
    @PostConstruct
    public void postConstruct() {
        System.out.println(dbUrl); //jdbc:mysql://localhost:3306/mytest
    }
}

	@Override
	public PropertySource<?> createPropertySource(String name, EncodedResource resource) throws IOException {
		return (name != null ? new ResourcePropertySource(name, resource) : new ResourcePropertySource(resource));
	}

@PropertySource(“classpath:jdbc-${spring.profiles.active}.properties”)

@ConfigurationProperties(prefix = "spring.mvc")
public class WebMvcProperties {}
 
//加載方式
	@Configuration
	@Conditional(DefaultDispatcherServletCondition.class)
	@ConditionalOnClass(ServletRegistration.class)
	// 此處采用這個(gè)注解，可議把WebMvcProperties這個(gè)Bean加載到容器里面去~~~
	// WebMvcProperties里面使用了`@ConfigurationProperties(prefix = "spring.mvc")`
	@EnableConfigurationProperties(WebMvcProperties.class) //加載MVC的配置文件
	protected static class DispatcherServletConfiguration {}

com.example.demo.name=${aaa:hi}
com.example.demo.age=11
com.example.demo.address[0]=北京 ?# 注意數(shù)組 List的表示方式 Map/Obj的方式各位可以自行嘗試
com.example.demo.address[1]=上海
com.example.demo.address[2]=廣州
com.example.demo.phone.number=1111111

@Component
@ConfigurationProperties(prefix = "com.example.demo")
public class People {
?
? ? private String name;
? ? private Integer age;
? ? private List<String> address;
? ? private Phone phone;
} ??

 ? @Bean
? ? @ConfigurationProperties(prefix = "com.example.demo")
? ? public People people() {
? ? ? ? return new People();
? ? }

@Component
@PropertySource("classpath:config/object.properties")
@ConfigurationProperties(prefix = "obj")
public class ObjectProperties {}