Spring中使用byName實現Beans自動裝配

以下內容引用自http://wiki.jikexueyuan.com/project/spring/beans-auto-wiring/spring-autowiring-byname.html：

此模式通過屬性名稱來指定自動裝配。Spring容器查看XML配置文件中auto-wire屬性設置為byName的bean。然后，它嘗試將其屬性與配置文件中相同名稱定義的bean進行匹配並連接。如果找到匹配，它將注入這些bean。否則，bean將不會被連線。

例如，如果一個bean定義在配置文件中設置為autowire="byName"，並且它包含一個spellChecker屬性（即它有一個setSpellChecker(...)方法），則Spring會查找一個名為spellChecker的bean定義，並使用它設置屬性。當然，還可以使用<property>標簽連接剩余的屬性。

例子：

pom.xml：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.jsoft.testspring</groupId>
  <artifactId>testautowiringbyname</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>testautowiringbyname</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    
    <!-- Spring Core --> <!-- http://mvnrepository.com/artifact/org.springframework/spring-core --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>4.1.4.RELEASE</version> </dependency> <!-- Spring Context --> <!-- http://mvnrepository.com/artifact/org.springframework/spring-context --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.1.4.RELEASE</version> </dependency>
    
  </dependencies>
</project>

SpellChecker.java：

package com.jsoft.testspring.testautowiringbyname;

public class SpellChecker {
    public SpellChecker(){
        System.out.println("SpellChecker無參數構造函數初始化");
    }
    
    public void checkSpelling(){
        System.out.println("SpellChecker檢查方法");
    }
}

TextEditor.java：

package com.jsoft.testspring.testautowiringbyname;

public class TextEditor {
    private SpellChecker spellChecker;
    
    public void setSpellChecker(SpellChecker spellChecker){
        System.out.println("TextEditor通過setter初始化");
        this.spellChecker = spellChecker;
    }
    
    public void spellCheck() {
        this.spellChecker.checkSpelling();
    }
    
}

beans.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd">
    
    <bean id="spellChecker" class="com.jsoft.testspring.testautowiringbyname.SpellChecker"></bean>
    
    <bean id="textEditor" class="com.jsoft.testspring.testautowiringbyname.TextEditor" autowire="byName">
    </bean>
   
</beans>

變化之前的beans.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd">
    
    <bean id="spellChecker" class="com.jsoft.testspring.testautowiringbyname.SpellChecker"></bean>
    
    <bean id="textEditor" class="com.jsoft.testspring.testautowiringbyname.TextEditor">
        <property name="SpellChecker" ref="spellChecker" />
    </bean>
   
</beans>

使用了自動裝配類型byName去實現，省略了<property>屬性。

App.java：

package com.jsoft.testspring.testautowiringbyname;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
        TextEditor textEditor = (TextEditor)applicationContext.getBean("textEditor");
        textEditor.spellCheck();
    }
}

運行結果：

 

測試工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test11/testautowiringbyname