使用@PropertySource读取配置文件通过@Value进行参数注入

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${}占位符注入属性，这个bean是必须的(PropertySourcesPlaceholderConfigurer)，

    //这个就是占位bean,

     //另一种方式是不用value直接用Envirment变量直接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 (显然这种注入的意义不大)

@Value ( "#{systemProperties['os.name']}" )

    private String systemPropertiesName; 

//效果等同于  是因为spring模版把系统变量否放进了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;

    }

//注入属性

    @Value ( "#{person.name}" )

    private String personName;

    @Test

    public void contextLoads() {

        System.out.println(personName); //fangshixiang

    }

    @Value ( "classpath:jdbc.properties" )

    private Resource resourceFile; // 注入文件资源

    @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);

        //输出：

        //db.username=fangshixiang

        //db.password=fang

        //db.url=jdbc:mysql://localhost:3306/mytest

        //db.driver-class-name=com.mysql.jdbc.Driver

    }

    @Value ( "http://HdhCmsTestbaidu测试数据" )

    private Resource testUrl; // 注入URL资源 

    @Test

    public void contextLoads() {

        System.out.println(testUrl); //URL [http://HdhCmsTestbaidu测试数据]

    }

@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;

//注入默认值

@Value ( "#{person.age?:20}" )

private String perAgeDefault;

//如果age22这个key根本就不存在，启动肯定会报错的

//@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 {}

//加载方式

     @Configuration

     @Conditional (DefaultDispatcherServletCondition. class )

     @ConditionalOnClass (ServletRegistration. class )

     // 此处采用这个注解，可议把WebMvcProperties这个Bean加载到容器里面去~~~

     // WebMvcProperties里面使用了`@ConfigurationProperties(prefix = "spring.mvc")`

     @EnableConfigurationProperties (WebMvcProperties. class ) //加载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  # 注意数组 List的表示方式 Map/Obj的方式各位可以自行尝试

com.example.demo.address[ 1 ]=上海

com.example.demo.address[ 2 ]=广州

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 {}