Guice提供了一种使用@provides方法创建与复杂对象绑定的方法.
@Provides public SpellChecker provideSpellChecker() { String dbUrl = "jdbc:mysql://localhost:5326/emp"; String user = "user"; int timeout = 100; SpellChecker SpellChecker = new SpellCheckerImpl(dbUrl, user, timeout); return SpellChecker; }
此方法是绑定模块的一部分,并提供要映射的复杂对象.请参阅下面的完整示例.
创建名为GuiceTester的java类.
GuiceTester.java
import com.google.inject.AbstractModule; import com.google.inject.Guice; import com.google.inject.Inject; import com.google.inject.Injector; import com.google.inject.Provides; 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( SpellChecker spellChecker) { this.spellChecker = spellChecker; } public void makeSpellCheck() { spellChecker.checkSpelling(); } } //Binding Module class TextEditorModule extends AbstractModule { @Override protected void configure() {} @Provides public SpellChecker provideSpellChecker() { String dbUrl = "jdbc:mysql://localhost:5326/emp"; String user = "user"; int timeout = 100; SpellChecker SpellChecker = new SpellCheckerImpl(dbUrl, user, timeout); return SpellChecker; } } //spell checker interface interface SpellChecker { public void checkSpelling(); } //spell checker implementation class SpellCheckerImpl implements SpellChecker { private String dbUrl; private String user; private Integer timeout; @Inject public SpellCheckerImpl(String dbUrl, String user, Integer timeout) { this.dbUrl = dbUrl; this.user = user; this.timeout = timeout; } @Override public void checkSpelling() { System.out.println("Inside checkSpelling." ); System.out.println(dbUrl); System.out.println(user); System.out.println(timeout); } }
编译并运行文件,你会看到以下输出.
Inside checkSpelling. jdbc:mysql://localhost:5326/emp user 100