Usage example of project bean in spring actual combat container

This article describes the usage of project bean in spring container. Share with you for your reference, as follows:

One configuration

<?xml version="1.0" encoding="GBK"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns="http://www.springframework.org/schema/beans"
   xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-4.0.xsd">
   <!-- 下面配置相当于如下代码：
   factorybean factory = new org.crazyit.app.factory.GetFieldfactorybean();
   factory.setTargetClass("java.awt.BorderLayout");
   factory.setTargetField("NORTH");
   north = factory.getObject(); -->
   <bean id="north" class="org.crazyit.app.factory.GetFieldfactorybean">
      <property name="targetClass" value="java.awt.BorderLayout"/>
      <property name="targetField" value="NORTH"/>
   </bean>
   <!-- 下面配置相当于如下代码：
   factorybean factory = new org.crazyit.app.factory.GetFieldfactorybean();
   factory.setTargetClass("java.sql.ResultSet");
   factory.setTargetField("TYPE_SCROLL_SENSITIVE");
   north = factory.getObject(); -->
   <bean id="theValue" class="org.crazyit.app.factory.GetFieldfactorybean">
      <property name="targetClass" value="java.sql.ResultSet"/>
      <property name="targetField" value="TYPE_SCROLL_SENSITIVE"/>
   </bean>
</beans>

II. Bean factory

package org.crazyit.app.factory;
import java.lang.reflect.*;
import org.springframework.beans.factory.factorybean;
public class GetFieldfactorybean implements factorybean<Object>
{
  private String targetClass;
  private String targetField;
  // targetClass的setter方法
  public void setTargetClass(String targetClass)
  {
    this.targetClass = targetClass;
  }
  // targetField的setter方法
  public void setTargetField(String targetField)
  {
    this.targetField = targetField;
  }
  // 返回工厂Bean所生产的产品
  public Object getObject() throws Exception
  {
    Class<?> clazz = Class.forName(targetClass);
    Field field = clazz.getField(targetField);
    return field.get(null);
  }
  // 获取工厂Bean所生产的产品的类型
  public Class<? extends Object> getObjectType()
  {
    return Object.class;
  }
  // 返回该工厂Bean所生成的产品是否为单例
  public boolean isSingleton()
  {
    return false;
  }
}

Three test categories

package lee;
import org.springframework.context.*;
import org.springframework.context.support.*;
public class SpringTest
{
  public static void main(String[] args)throws Exception
  {
    ApplicationContext ctx = new
      ClassPathXmlApplicationContext("beans.xml");
    // 下面2行代码获取的factorybean的产品
    System.out.println(ctx.getBean("north"));
    System.out.println(ctx.getBean("theValue"));
    // 下面代码可获取的factorybean本身
    System.out.println(ctx.getBean("&theValue"));
  }
}

IV. test results

V. description

java. awt. Borderlayout is defined as follows

public class BorderLayout implements LayoutManager2,java.io.Serializable {
  /**
   * The north layout constraint (top of container).
   */
  public static final String NORTH = "North";
}

java. sql. The resultset is defined as follows

public interface ResultSet extends Wrapper,AutoCloseable {
  int TYPE_SCROLL_SENSITIVE = 1005;
}

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