Spring入门学习(一)-白红宇

Spring入门学习(一)

阅读量：5085 次

发布时间：2019-06-13

本文共 4077 字，大约阅读时间需要 13 分钟。

Spring的主要功能是控制反转和面向切面编程,下面我们就来编写第一个spring的程序来体验一下控制反转

首先是加载配置文件

下面我们在程序中加载配置文件

ApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");

然后新建类

package com.service.impl;import com.service.Service;public class ServiceBean implements Service {@Overridepublic void save(){System.out.println("save()");}}

抽取出类的接口 refactor----->extract interface

然后在测试方法中控制反转

package junit.test;import static org.junit.Assert.*;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.service.Service;public class SpringTest {@Testpublic void test() {ApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");Service service = (Service)ac.getBean("service");service.save();}}

下面我们来看看是怎么控制反转的吧

首先新建类来解析配置文件，然后把配置文件中的bean中的属性提取出来创建对象，通过相应的方法刚返回给页面

1 package com.dom4j.test; 2  3 import java.io.File; 4 import java.util.HashMap; 5 import java.util.Iterator; 6 import java.util.Map; 7 import java.util.Set; 8  9 import org.dom4j.Attribute;10 import org.dom4j.Document;11 import org.dom4j.DocumentException;12 import org.dom4j.DocumentHelper;13 import org.dom4j.Element;14 import org.dom4j.io.SAXReader;15 16 import com.service.Service;17 import com.sun.beans.decoder.DocumentHandler;18 19 public class DomeStuTest {20     21     private Map
     
       map = new HashMap
      
       ();22     private Map
       
         objMap = new HashMap
        
         ();23     24     public  DomeStuTest(String xml){25         String xmlPath = getClass().getClassLoader().getResource(xml).getPath();26         Document document = null;27         SAXReader reader = new SAXReader();28         29         try {30             document = reader.read(new File(xmlPath));31         } catch (DocumentException e) {32             e.printStackTrace();33         }34         35         //获取根节点36         Element root = document.getRootElement();37         38         //获取根节点下的子节点39         Iterator it = root.elementIterator("bean");40         while(it.hasNext()){41             Element ele = (Element)it.next();42             Attribute attr_name  = ele.attribute("name");43             Attribute attr_class = ele.attribute("class");44             45             map.put(attr_name.getValue(), attr_class.getValue());46         }47         48         //实例化容器内的对象并存储49         Set
         
           set = map.keySet();50         Iterator its = set.iterator();51         while(its.hasNext()){52             String key    = (String)its.next();53             String value  = map.get(key);54             try {55                 Class clazz = Class.forName(value);56                 Object obj = clazz.newInstance();57                 objMap.put(key, obj);58             } catch (ClassNotFoundException e) {59                 e.printStackTrace();60             } catch (InstantiationException e) {61                 e.printStackTrace();62             } catch (IllegalAccessException e) {63                 e.printStackTrace();64             }65             66         }67         68     }69     70     //取得对象71     public Object get(String name){72         Object obj = null;73         Set
          
            set = objMap.keySet();74 Iterator it = set.iterator();75 while(it.hasNext()){76 String key = (String)it.next();77 if(key.equals(name)){78 obj = objMap.get(key);79 }80 }81 return obj;82 }83 84 }

然后在页面这样就可以获得对象

package junit.test;import org.junit.Test;import com.dom4j.test.DomeStuTest;import com.service.Person;import com.service.Service;public class SpringTest {    @Test    public void test() {//        ApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");//        Service service = (Service)ac.getBean("service");//        service.save();                DomeStuTest dst = new DomeStuTest("spring.xml");        Service service = (Service)dst.get("service");        service.save();        Person  person  = (Person)dst.get("person");        person.showMessage();    }}

转载于:https://www.cnblogs.com/dbqjava/p/4446532.html

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