自定义spring容器

最新推荐文章于 2023-04-19 16:59:05 发布

lux_lu

最新推荐文章于 2023-04-19 16:59:05 发布

阅读量625

点赞数

分类专栏： spring2.5

spring2.5 专栏收录该内容

3 篇文章

订阅专栏

本文介绍了一种基于Spring框架的自定义容器实现方法，通过解析XML配置文件来注册和实例化Bean，展示了如何使用该容器替代Spring的标准ApplicationContext。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

<?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-2.5.xsd">
           <bean id="personService" class="com.icss.service.impl.PersonServiceBean"></bean>

</beans>

=================================

package com.icss.service;

public interface PersonService {

public abstract void save();

}

================================

package com.icss.service.impl;

import com.icss.service.PersonService;

public class PersonServiceBean implements PersonService {
   @Override
   public void save(){
       System.out.println("我是save（）方法");
   }
}

===============================

package junit.test;

public class BeanDefinition {
   private String id;
   private String className;
   public BeanDefinition(String id, String className) {
       super();
       this.id = id;
       this.className = className;
   }
   public String getId() {
       return id;
   }
   public void setId(String id) {
       this.id = id;
   }
   public String getClassName() {
       return className;
   }
   public void setClassName(String className) {
       this.className = className;
   }
}

===============================

package junit.test;

import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.XPath;
import org.dom4j.io.SAXReader;

/**
* 自定义容器
* @author Administrator
*
*/
public class IcssClassPathXMLApplicationContext {

   private List<BeanDefinition> beanDefinitions = new ArrayList<BeanDefinition>();
   private Map<String, Object> sigletons = new HashMap<String, Object>();

   public IcssClassPathXMLApplicationContext(String filename){
       this.readXML(filename);
       this.instanceBeans();
   }
   /**
   * 完成bean的实例化
   */
   private void instanceBeans() {
       for(BeanDefinition beanDefinition : beanDefinitions){
           try {
               if(beanDefinition.getClassName() != null && !"".equals(beanDefinition.getClassName().trim()))
               sigletons.put(beanDefinition.getId(), Class.forName(beanDefinition.getClassName()).newInstance());
           } catch (Exception e) {
               e.printStackTrace();
           }
       }
   }
   /**
   * 读取xml配置文件
   * @param filename
   */

   private void readXML(String filename) {
       SAXReader saxReader = new SAXReader();
       Document document = null;
       try {
           URL xmlpath = this.getClass().getClassLoader().getResource(filename);
           document = saxReader.read(xmlpath);
           Map<String, String> nsMap = new HashMap<String, String>();
           //加入命名空间
           nsMap.put("ns", "http://www.springframework.org/schema/beans");
           //创建beans/bean查询路径
           XPath xsub = document.createXPath("//ns:beans/ns:bean");
           xsub.setNamespaceURIs(nsMap);//设置命名空间
           List<Element> beans = xsub.selectNodes(document);
           for(Element element : beans){
               String id = element.attributeValue("id");//获取id属性值
               String clazz = element.attributeValue("class");//获取class属性值
               BeanDefinition beanDefine = new BeanDefinition(id, clazz);
               beanDefinitions.add(beanDefine);
           }
       } catch (Exception e) {

       }
   }
   /**
   * 获取bean实例
   * @param beanName
   * @return
   */
   public Object getBean(String beanName){
       return this.sigletons.get(beanName);
   }
}

===============================

package junit.test;

import static org.junit.Assert.*;

import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.icss.service.PersonService;

public class SpringTest {

   @Test
   public void test() {
       ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
       PersonService personService = (PersonService) ctx.getBean("personService");
       personService.save();
   }


   /**
   * 使用自定义容器
   */
   @Test
   public void testInstance() {
       IcssClassPathXMLApplicationContext ctx = new IcssClassPathXMLApplicationContext("beans.xml");
       PersonService personService = (PersonService) ctx.getBean("personService");
       personService.save();
   }
}