Question

界面 -

public interface Add {
    public int add(int a, int b)
}

实施1 -

class MartianAdd implements Add 
public int add(int a, int b) {
    return -a+b;
}
}

实施2-

public class SimpleAdd implements Add {
public SimpleAdd() {}
public int add(int a, int b) {
    return a + b
}
}


class Bindings extends AbstractModule {
protected void configure() {
    bind(Add).annotatedWith(Names.named('Earth')).to(SimpleAdd)
    bind(Add).annotatedWith(Names.named('Mars')).to(MartianAdd)
}
}

主要课程 -

class Test {
public static void main(String[] args) {
    Injector injector = Guice.createInjector(new Bindings())
    @Named('Mars') Add a = injector.getInstance(Add)
    print a.class
    print a.add(5, 8)
}
}

例外 -

Exception in thread "main" com.google.inject.ConfigurationException: Guice configuration errors:

1) No implementation for in.ksharma.Add was bound.
  while locating in.ksharma.Add

Guice为什么不加载我的绑定？

Answer 1

这是问题，我相信：

@Named('Mars') Add a = injector.getInstance(Add)

您只是询问 Add的实例 - 您分配结果的变量具有@Named注释的事实与Guice无关。我相信你需要使用Injector.getInstance(Key)和正确的类的密钥来使用正确的名称绑定，例如

Add add = injector.getInstance(Key.get(Add, Names.named('Mars')))

Guice不加载Bindings

1 个答案: