差異處
這裏顯示兩個版本的差異處。
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java:guice:helloworld [2013/11/08 17:55] tony |
java:guice:helloworld [2023/06/25 09:48] |
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| - | {{tag>java guice}} | ||
| - | ====== Hello World! ====== | ||
| - | 這個範例主要了解Guice如何實做Dependency Injection(DI)。 | ||
| - | ===== 準備 ===== | ||
| - | - 至[[https://code.google.com/p/google-guice/downloads/list|Guice官網]]下載lib包。我下載了 guice-4.0-beta.zip。 | ||
| - | - 建立一個Eclipse Java Project並把壓縮的內容解壓到Project libs目錄。 | ||
| - | - 將guice-4.0-beta.tar與javax.inject.jar加入build path中。 | ||
| - | ===== 第一隻Guice程式 ===== | ||
| - | 範例程式包含介面IPrintServer、實作類別ConsolePrinter、用戶端PrinterClient與Guice所需要的configuration模組PrinterModule。\\ | ||
| - | PrintService介面: | ||
| - | <file java IPrintService.java> | ||
| - | package org.tonylin.practice.guice; | ||
| - | |||
| - | public interface IPrintService { | ||
| - | void print(String ... strs); | ||
| - | } | ||
| - | </file> | ||
| - | ConsolePrinter提供Console類型服務的PrintService: | ||
| - | <file java ConsolePrinter.java> | ||
| - | package org.tonylin.practice.guice; | ||
| - | |||
| - | public class ConsolePrinter implements IPrintService { | ||
| - | |||
| - | @Override | ||
| - | public void print(String... strs) { | ||
| - | for( String str : strs ){ | ||
| - | System.out.println(str); | ||
| - | } | ||
| - | } | ||
| - | } | ||
| - | </file> | ||
| - | PrinterClient是使用到PrintService的用戶端，我們必須針對提供注入服務的函式宣告為@Inject: | ||
| - | <file java PrinterClient.java> | ||
| - | package org.tonylin.practice.guice; | ||
| - | |||
| - | import com.google.inject.Guice; | ||
| - | import com.google.inject.Inject; | ||
| - | import com.google.inject.Injector; | ||
| - | |||
| - | public class PrinterClient { | ||
| - | private IPrintService mPrintService = null; | ||
| - | |||
| - | |||
| - | @Inject | ||
| - | public void setPrintService(IPrintService aPrintService){ | ||
| - | mPrintService = aPrintService; | ||
| - | } | ||
| - | |||
| - | public IPrintService getPrintService(){ | ||
| - | return mPrintService; | ||
| - | } | ||
| - | |||
| - | public void print(String ... strs){ | ||
| - | mPrintService.print(strs); | ||
| - | } | ||
| - | |||
| - | public static void main(String[] args) { | ||
| - | Injector injector = Guice.createInjector(new PrinterModule()); | ||
| - | PrinterClient printerClient = injector.getInstance(PrinterClient.class); | ||
| - | printerClient.print("test1", "test2"); | ||
| - | } | ||
| - | |||
| - | } | ||
| - | </file> | ||
| - | PrinterModule負責建立PrinterClient與實際提供服務類別的連結，在這裡我透過System Propertes去決定我所要注入給PrinterClient的IPrintService實體: | ||
| - | <file java PrinterModule.java> | ||
| - | package org.tonylin.practice.guice; | ||
| - | |||
| - | import com.google.inject.Binder; | ||
| - | import com.google.inject.Module; | ||
| - | |||
| - | public class PrinterModule implements Module { | ||
| - | @Override | ||
| - | public void configure(Binder binder) { | ||
| - | binder.bind(IPrintService.class).to(ConsolePrinter.class); | ||
| - | } | ||
| - | } | ||
| - | </file> | ||
| - | |||
| - | 執行PrinterClient的main可以發現test1與test2字串顯示在螢幕上。\\ | ||
| - | \\ | ||
| - | 友藏內心獨白: 照這樣看來Guice是蠻簡單的! | ||
| - | ===== ===== | ||
| - | ---- | ||
| - | \\ | ||
| - | ~~DISQUS~~ | ||
