Guice 简明教程
Google Guice - Constructor Bindings
Guice 提供了一种方法,可以使用 toConstructor() 方法创建具有对象的特定构造函数的绑定。
@Override
protected void configure() {
try {
bind(SpellChecker.class)
.toConstructor(SpellCheckerImpl.class.getConstructor(String.class));
} catch (NoSuchMethodException | SecurityException e) {
System.out.println("Required constructor missing");
}
}
请参见以下完整示例。
Complete Example
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.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( SpellChecker spellChecker) {
this.spellChecker = spellChecker;
}
public void makeSpellCheck(){
spellChecker.checkSpelling();
}
}
//Binding Module
class TextEditorModule extends AbstractModule {
@Override
protected void configure() {
try {
bind(SpellChecker.class)
.toConstructor(SpellCheckerImpl.class.getConstructor(String.class));
} catch (NoSuchMethodException | SecurityException e) {
System.out.println("Required constructor missing");
}
bind(String.class)
.annotatedWith(Names.named("JDBC"))
.toInstance("jdbc:mysql://localhost:5326/emp");
}
}
//spell checker interface
interface SpellChecker {
public void checkSpelling();
}
//spell checker implementation
class SpellCheckerImpl implements SpellChecker {
private String dbUrl;
public SpellCheckerImpl(){}
public SpellCheckerImpl(@Named("JDBC") String dbUrl){
this.dbUrl = dbUrl;
}
@Override
public void checkSpelling() {
System.out.println("Inside checkSpelling." );
System.out.println(dbUrl);
}
}