Guice 学习（六）使用Provider注入服务（ Provider Inject Service）

1、定义接口

package com.guice.providerInject;

import com.google.inject.ProvidedBy;

public interface Service {
public void execute();
}

2、定义实现类

package com.guice.providerInject;

public class OneService implements Service {
@Override
public void execute() {
System.out.println("Hello!  I'M Service 1!");

}
}

3、Provider实现类

package com.guice.providerInject;

import com.google.inject.Provider;

/**
* TODO : 每次新建一个新的OneService对象出来
*
* @author E468380
*/
public class OneServiceProvider implements Provider<Service> {

@Override
public Service get() {
return new OneService();
}

}

4、ProviderServiceDemo 測试类

package com.guice.providerInject;

import com.google.inject.Binder;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Module;

/**
* 使用上面OneServiceProvider来新建实例 当然假设想自己主动注入（不使用Module手动关联）服务的话。能够使用@ProviderBy注解。

*
*/
public class ProviderServiceDemo {
@Inject
private Service service;

public static void main(String[] args) {
ProviderServiceDemo instance = Guice.createInjector(new Module() {

@Override
public void configure(Binder binder) {
binder.bind(Service.class).toProvider(OneServiceProvider.class);
}
}).getInstance(ProviderServiceDemo.class);
instance.service.execute();// Hello! I'M Service 1!

}
}

5、ProviderServiceDemo2測试类

package com.guice.providerInject;

import com.google.inject.ProvidedBy;

@ProvidedBy(OneServiceProvider.class)
public interface Service {
public void execute();
}

package com.guice.providerInject;

import com.google.inject.Guice;

public class ProviderServiceDemo2 {
public static void main(String[] args) {
ProviderServiceDemo2 instance = Guice.createInjector().getInstance(ProviderServiceDemo2.class);
// instance.service.execute(); //发现不起作用不知何解 ？
}
}

6、ProviderServiceDemo3測试类

package com.guice.providerInject;

import com.google.inject.Binder;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Module;
import com.google.inject.Provider;

/**
* TODO :能够注入Provider而不是注入服务
* ◇因为我们OneServiceProvider每次都是构造一个新的服务出来，
* 因此在类ProviderServiceDemo3中的provider每次获取的服务也是不一样的。
*
* @author E468380
*/
public class ProviderServiceDemo3 {
@Inject
private Provider<Service> provider;

public static void main(String[] args) {

ProviderServiceDemo3 instance = Guice.createInjector(new Module() {

@Override
public void configure(Binder binder) {
binder.bind(Service.class).toProvider(OneServiceProvider.class);
}
}).getInstance(ProviderServiceDemo3.class);

instance.provider.get().execute();// Hello! I'M Service 1!
}
}