Java 春天@Autowired @Lazy
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Spring @Autowired @Lazy
提问by DD.
I'm using Spring annotations and I want to use lazy initialization.
我正在使用 Spring 注释并且我想使用延迟初始化。
I'm running into a problem that when I want to import a bean from another class I am forced to use @Autowiredwhich does not seem to use lazy init. Is there anyway to force this lazy init behaviour?
我遇到了一个问题，当我想从另一个类导入一个 bean 时，我被迫使用@Autowired它似乎没有使用惰性初始化。反正有没有强制这种懒惰的初始化行为？
In this example I do not want to see "Loading parent bean" ever being printed as I am only loading childBeanwhich has no dependencies on lazyParent.
在这个例子中，我不希望看到“加载父 bean”被打印出来，因为我只加载childBean不依赖于lazyParent.
@Configuration
public class ConfigParent {
@Bean
@Lazy
public Long lazyParent(){
System.out.println("Loading parent bean");
return 123L;
}
}
@Configuration
@Import(ConfigParent.class)
public class ConfigChild {
private @Autowired Long lazyParent;
@Bean
public Double childBean() {
System.out.println("loading child bean");
return 1.0;
}
@Bean
@Lazy
public String lazyBean() {
return lazyParent+"!";
}
}
public class ConfigTester {
public static void main(String[] args) {
ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigChild.class);
Double childBean=ctx.getBean(Double.class);
System.out.println(childBean);
}
}
采纳答案by skaffman
Because you're using @Autowired Long lazyParent, Spring will resolve that dependency when the context starts up. The fact that lazyBeanis @Lazyis irrelevent.
因为您使用的是@Autowired Long lazyParent，Spring 将在上下文启动时解决该依赖项。这事实上lazyBean是@Lazy无关紧要，。
Try this as an alternative, although I'm not 100% convinced this wil lwork as you want it to:
试试这个作为替代方案，虽然我不是 100% 相信这会如你所愿：
@Configuration
@Import(ConfigParent.class)
public class ConfigChild {
private @Autowired ConfigParent configParent;
@Bean
public Double childBean() {
System.out.println("loading child bean");
return 1.0;
}
@Bean
@Lazy
public String lazyBean() {
return configParent.lazyParent() + "!";
}
}
P.S. I hope you're not reallydefining Strings, Doubles and Longs as beans, and that this is just an example. Right...?
PS 我希望你没有真正将字符串、双打和长整型定义为 bean，这只是一个例子。对...？
回答by Bochu
Try
尝试
@Lazy @Autowired Long lazyParent;
