Guice 将对象注入 class 构造函数

Question

我刚开始为新项目寻找 Guice。我有这样的东西

ConfigImpl class ans Config 接口

 interface Config{...}

 class ConfigImpl implements Config {
   private static final Map<> propMap;
   public ConfigImpl(Map<> propMap) {
     this.propMap = someProps;
   }
 }

Guice 注入是我想出来的

public class MyInjector extends AbstractModule {
  protected void configure() {
    bind(Config.class).to(ConfigImpl.class)
  }
}

最后

public SomeClass {
  Config someConfig;
  Injector injector = Guice.createInjector(new MyInjector());
  someConfig = injector.getInstance(Config.class);          
}

现在我很困惑，因为我找不到将 propMap 传递到 ConfigImpl 的方法 class。我想知道在 Guice 中执行此操作的正确方法。谢谢！

Answer 1

您应该从您的模块中注入 propMaps：

public class MyInjector extends AbstractModule {
  private final Map<String,String> mapProps;
  public MyInjector(Map<String,String> mapProps) {
    this.mapProps = mapProps;
  }
  protected void configure() {
    bind(Config.class).to(ConfigImpl.class).in(Scope.SINGLETON);         // You most than likely want this
    bind(new TypeLiteral<Map<String,String>>() {}).toInstance(mapProps); // binding for the map.
  }
}

并像这样使用它：

public class SomeClass {
  void doSomething() {
    Map<String,String> mapProps = ... ;
    Injector injector = Guice.createInjector(new MyInjector(mapProps));
    Config someConfig = injector.getInstance(Config.class);          
  }
}

另外，你应该修复你的 ConfigImpl class:

class ConfigImpl implements Config {
  private final Map<String,String> propMap;
  @Inject                                         // mandatory since you use a non-default constructor
  public ConfigImpl(Map<String,String> propMap) { // add the generic type of the map
    this.propMap = propMap;
  }
}

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