[email protected]條件註冊

@Condition來指定一定條件下注冊元件對像

All Conditions that must match in order for the component to be registered.

所有的條件必須實現Condition介面，重寫matches方法，來決定元件是否註冊

配置類

@Configuration
public class ConditionConfig {
    @Conditional(WindowsCondition.class)
    @Bean("bill"
 
)
    public Person bill(){
        return new Person("bill",10);
    }

    @Conditional(LinuxCondition.class)
    @Bean("Linus")
    public Person person(){
        return new Person("Linus",10);
    }
}

WindowsCondition 判斷windows環境

public class WindowsCondition implements Condition {
    public
 
 boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        //獲取當前執行環境資訊
        Environment environment = context.getEnvironment();
        //獲取當前環境名稱
        String osName = environment.getProperty("os.name");
        return osName.contains("Windows");
    }
}

LinuxCondition 判斷Linux環境

public class LinuxCondition implements Condition {
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        //獲取當前執行環境資訊
        Environment environment = context.getEnvironment();
        //獲取當前環境名稱
        String osName = environment.getProperty("os.name");
        return osName.contains("Linux");
    }
}

測試（系統為Window 7）

@Test
public void person() {
    Map<String, Person> beansOfType = annotationConfigApplicationContext.getBeansOfType(Person.class);
    System.out.println("beansOfType = " + beansOfType);
}

設定vm的變數來模擬Linux環境，Run Configurations->VM options

新增 Dos.name=Linux

執行結果