Changes between Version 17 and Version 18 of waue/2011/spring

Timestamp:

Aug 26, 2011, 4:07:03 PM (13 years ago)

Author:

waue

Comment:

--

waue/2011/spring

@@ -249 +249 @@
 
 
-
+ == bean 間的引用 == 
+
+在定義Bean時，除了直接指定值給屬性值之外，還可以直接參考定義檔中的其它Bean，例如HelloBean是這樣的話：
+
+ *  HelloBean.java
+
+{{{
+#!java
+package onlyfun.caterpillar; 
+
+import java.util.Date; 
+
+public class HelloBean { 
+    private String helloWord; 
+    private Date date; 
+    
+    public void setHelloWord(String helloWord) { 
+        this.helloWord = helloWord; 
+    } 
+    public String getHelloWord() { 
+        return helloWord; 
+    } 
+    public void setDate(Date date) { 
+        this.date = date; 
+    }    
+    public Date getDate() { 
+        return date; 
+    } 
+}
+}}}
+
+在以下的Bean定義檔中，先定義了一個dateBean，之後helloBean可以直接參考至dateBean，Spring會幫我們完成這個依賴關係：
+
+ *  beans-config.xml
+
+{{{
+#!xml
+<?xml version="1.0" encoding="UTF-8"?> 
+<!DOCTYPE beans PUBLIC "-//SPRING/DTD BEAN/EN" 
+  "http://www.springframework.org/dtd/spring-beans.dtd"> 
+
+<beans> 
+    <bean id="dateBean" class="java.util.Date"/> 
+    
+    <bean id="helloBean" class="onlyfun.caterpillar.HelloBean"> 
+        <property name="helloWord"> 
+            <value>Hello!</value> 
+        </property> 
+        <property name="date"> 
+            <ref bean="dateBean"/> 
+        </property> 
+    </bean> 
+</beans>
+}}}
+
+直接指定值或是使用<ref>直接指定參考至其它的Bean，撰寫以下的程式來測試Bean的依賴關係是否完成：
+
+ *  SpringDemo.java
+
+{{{
+#!java
+package onlyfun.caterpillar; 
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.support.FileSystemXmlApplicationContext; 
+
+public class SpringDemo { 
+    public static void main(String[] args) { 
+        ApplicationContext context = 
+            new FileSystemXmlApplicationContext("beans-config.xml");
+         
+        HelloBean hello = 
+            (HelloBean) context.getBean("helloBean");
+        System.out.print(hello.getHelloWord());
+        System.out.print(" It's ");
+        System.out.print(hello.getDate());
+        System.out.println(".");
+    } 
+}
+}}}
+
+ * 執行結果如下：
+
+{{{
+Hello! It's Sat Oct 22 15:36:48 GMT+08:00 2005.
+}}}
 
  = Dependency Injection =