如何为来自不同属性文件的 Bean 列表配置 Spring 配置？

Question

我有工作 Spring XML 配置，我想将它移到 Annotation Config。

问题是如何从不同的属性文件创建不同的 bean。

这是 XML 片段：

<bean id="auditorium1" class="net.lelyak.edu.entity.Auditorium"
      c:name="${auditorium1.name}" c:numberOfSeats="${auditorium1.number-of-seats}" 
      c:vipSeats="${auditorium1.vip-seats}"/>
<bean id="auditorium2" class="net.lelyak.edu.entity.Auditorium"
      c:name="${auditorium2.name}" c:numberOfSeats="${auditorium2.number-of-seats}" 
      c:vipSeats="${auditorium2.vip-seats}"/>
<bean id="auditorium3" class="net.lelyak.edu.entity.Auditorium"
      c:name="${auditorium3.name}" c:numberOfSeats="${auditorium3.number-of-seats}" 
      c:vipSeats="${auditorium3.vip-seats}"/>

<util:list id="auditoriumsList">
    <ref bean="auditorium1"/>
    <ref bean="auditorium2"/>
    <ref bean="auditorium3"/>
</util:list>

<bean id="conversionService"
      class="org.springframework.context.support.ConversionServiceFactoryBean" /> 

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>classpath:properties/auditorium1.properties</value>
            <value>classpath:properties/auditorium2.properties</value>
            <value>classpath:properties/auditorium3.properties</value>
            <value>classpath:db/dp.properties</value>
        </list>
    </property>
    <property name="ignoreResourceNotFound" value="true"/>
    <property name="systemPropertiesMode">
        <util:constant
                static-field="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.SYSTEM_PROPERTIES_MODE_OVERRIDE"/>
    </property>
</bean>

属性文件示例：

auditorium1.name=yellow
auditorium1.number-of-seats=150
auditorium1.vip-seats=1,2,3,4,5,6,7,8,9

我想将它移动到 Annotation 配置，例如：

@Configuration
public class AuditoriumConfiguration {

    @Bean
    public Auditorium auditorium1() {
        return new Auditorium();
    }

    @Bean
    public Auditorium auditorium2() {
        return new Auditorium();
    }

    @Bean
    public Auditorium auditorium3() {
        return new Auditorium();
    }

    @Bean
    public List<Auditorium> auditoriumsList() {
        return Arrays.asList(auditorium1(), auditorium2(), auditorium3());
    }

    @Bean
    public ConversionService conversionService() {
        return new DefaultConversionService();
    }
}

这是礼堂 POJO：

@Component
public class Auditorium {
    private Integer id;
    private String name;
    private Integer numberOfSeats;
    private Set<Integer> vipSeats;
    // get / set

如何为每个属性文件创建不同的 Auditorium 实例？

我想我可以使用@Value ，但我找不到每个属性文件的方法创建对象。

有什么建议吗？

Answer 1

首先，您不需要列表，如果您需要类型列表，只需将@Autowired添加到集合中，spring 就会将该 bean 的所有类型注入到该集合中。

要获取属性，您可以使用Environment并且您可能希望为此添加一个帮助程序/工厂方法。

默认情况下已经配置了转换服务，因此无需添加。

要加载配置文件，请将@PropertySource添加到您的配置类。 如果您需要@Value或替换占位符，您需要添加一个PropertySourcesPlaceholderConfigurer作为static bean。

基本上，这样的事情应该达到你想要的。

@Configuration
@PropertySource({"classpath:properties/auditorium1.properties",
        "classpath:properties/auditorium2.properties",
        "classpath:properties/auditorium3.properties",
        "classpath:db/dp.properties"})
public class AuditoriumConfiguration {

    @Autowired
    private Environment env;

    @Bean
    public static PropertySourcesPlaceholderConfigurer placeholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }

    private Auditorium createAuditorium(String prefix) {
        String nameString = env.getProperty(prefix + ".name");
        String strNumberOfSeats = env.getProperty(prefix + ".number-of-seats");
        Integer[] integers = env.getProperty(prefix + ".vip-seats", Integer[].class);
        Set<Integer> integerSet = Arrays.stream(integers).collect(Collectors.toSet());

        Auditorium auditorium = new Auditorium();
        auditorium.setName(nameString);
        auditorium.setNumberOfSeats(Integer.valueOf(strNumberOfSeats));
        auditorium.setVipSeats(integerSet);
        return auditorium;
    }

    @Bean
    public Auditorium auditorium1() {
        return createAuditorium("auditorium1");
    }

    @Bean
    public Auditorium auditorium2() {
        return createAuditorium("auditorium2");
    }

    @Bean
    public Auditorium auditorium3() {
        return createAuditorium("auditorium3");
    }
}

现在，如果您想要这些类的列表，只需添加一个List<Auditorium>并且 spring 会将所有依赖项注入该列表。

public class MyClass {
    @Autowired
    private List<Auditorium> auditoriums;
}

Answer 2

@Configuration
public class DataSourceConfig {
    @Bean
    public DataSource dataSource() {
        return new DriverManagerDataSource(...);
    }
}

@Configuration
@Import({ DataSourceConfig.class, TransactionConfig.class })
public class AppConfig extends ConfigurationSupport {
    // bean definitions here can reference bean definitions in DataSourceConfig or TransactionConfig
}


@Configuration
@PropertySource("classpath:/com/myco/app.properties")
//@ResourceBundles("classpath:/org/springframework/config/java/simple")

public class AppConfig {

    @Value("${jdbc.url}")
    //@ExternalValue("datasource.username")
    private String url;

    @Value("${jdbc.username}")
    private String username;

    @Value("${jdbc.password}")
    private String password;
    
     @Bean
    public TestBean testBean () {
        HashMap<String, Integer> map = new HashMap<>();
        map.put("one", 1);
        map.put("two", 2);
        return new TestBean(map);
    }
    
    @Bean
public Map<Integer, String> nameMap(){
    Map<Integer, String>  nameMap = new HashMap<>();
    nameMap.put(1, "John");
    nameMap.put(2, "Adam");
    nameMap.put(3, "Harry");
    return nameMap;
}

private Map<Integer, String> nameMap;
 
    @Autowired
    public void setNameMap(Map<Integer, String> nameMap) {
        this.nameMap = nameMap;
    }
 
    public void printNameMap() {
        System.out.println(nameMap);
    }
    
    

@Bean
    public List<String> nameList() {
        return Arrays.asList("John", "Adam", "Harry");
    }
    
    //set 
    private Set<String> nameSet;
 
    public AppConfig(Set<String> strings) {
        this.nameSet = strings;
    }
 
 @Bean
public AppConfig getCollectionsBean() {
    return new AppConfig(new HashSet<>(Arrays.asList("John", "Adam", "Harry")));
}


 
    public void printNameSet() {
     
   System.out.println(nameSet);
    }
    
    
    private Set<String> nameSet;
 
    public AppConfig(Set<String> strings) {
        this.nameSet = strings;
    }
 
    public void printNameSet() {
        System.out.println(nameSet);
    }
    
    
    

    
    }
    
    public static void main(String[] args) {
    ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class);
    TestBean bean = context.getBean(TestBean.class);
        System.out.println(bean.getMap());
}