Google Guice @Named

Google Guice 还提供了另一种无需创建自定义注释即可映射绑定的方法。它允许使用@Named 注解。

使用@Named 注解映射

bind(SpellChecker.class).annotatedWith(Names.named("OpenOffice")).to(OpenOfficeWordSpellCheckerImpl.class);

使用@Named 注解注入

@Inject
public TextEditor(@Named("OpenOffice") SpellChecker spellChecker) {
   this.spellChecker = spellChecker;
}

Google Guice @Named 注解完整示例

创建一个名为 GuiceTester 的 Java 类。

GuiceTester.java

package com.yiidian;

import com.google.inject.AbstractModule;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.name.Named;
import com.google.inject.name.Names;

public class GuiceTester {
   public static void main(String[] args) {
      Injector injector = Guice.createInjector(new TextEditorModule());
      TextEditor editor = injector.getInstance(TextEditor.class);
      editor.makeSpellCheck();
   } 
}

class TextEditor {
   private SpellChecker spellChecker;
   

   @Inject
   public TextEditor(@Named("OpenOffice") SpellChecker spellChecker) {
      this.spellChecker = spellChecker;      
   }

   public void makeSpellCheck(){
      spellChecker.checkSpelling(); 
   }  
}

//Binding Module
class TextEditorModule extends AbstractModule {

   @Override
   protected void configure() {
      bind(SpellChecker.class).annotatedWith(Names.named("OpenOffice"))
         .to(OpenOfficeWordSpellCheckerImpl.class);
   } 
}

//spell checker interface
interface SpellChecker {
   public void checkSpelling();
}

//spell checker implementation
class SpellCheckerImpl implements SpellChecker {

   @Override
   public void checkSpelling() {
      System.out.println("Inside checkSpelling." );
   } 
}

//subclass of SpellCheckerImpl
class OpenOfficeWordSpellCheckerImpl extends SpellCheckerImpl{
   @Override
   public void checkSpelling() {
      System.out.println("Inside OpenOfficeWordSpellCheckerImpl.checkSpelling." );
   } 
}

输出

编译并运行该文件，您将看到以下输出。