spring基础---->spring自定义初始化（二）

　　这里新增了对ref属性的支持，并且过滤了已经解析的元素。人生有两个词很棒，一言不合和不提也罢。

spring自定义对ref属性支持

项目的结构如下：新增一个ThirdBean类，修改了ParseXmlBean和MainTest两个类。

一、ThirdBean是一个测试的Bean类

package com.spring1.bean;

public class ThirdBean {

    private SecondBean secondBean;

    private String username;

    public SecondBean getSecondBean() {

        return secondBean;

    }

    public void setSecondBean(SecondBean secondBean) {

        this.secondBean = secondBean;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public void printUserInfo() {

        System.out.println(secondBean.getUserInfo() + ", " + username);

    }

}

二、修改的xml解析类ParseXmlBean

package com.spring1.parse;

import com.spring1.SpringUtil;

import com.spring1.factory.BeanFactory;

import org.dom4j.Document;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

import java.io.InputStream;

import java.lang.reflect.Method;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

public class ParseXmlBean {

    static BeanFactory beanFactory = new BeanFactory();

    static Map<String, Element> elementMap = new HashMap<>();

    public static BeanFactory parseXmlBean(String filepath) {

        SAXReader reader = new SAXReader();

        try {

            InputStream stream = ParseXmlBean.class.getClassLoader().getResourceAsStream(filepath);

            Document document = reader.read(stream);

            Element rootElement = document.getRootElement();

            List<Element> entries = rootElement.elements("bean");

            // 这个map记录id和元素，由于ref的原因

            for (Element entry : entries) {

                String beanId = entry.attributeValue("id");

                elementMap.put(beanId, entry);

            }

            for (Element entry : entries) {

                parseObjectElement(entry);

            }

        } catch (Exception e) {

            e.printStackTrace();

        }

        return beanFactory;

    }

    private static String getMethodName(String name) {

        return "set" + SpringUtil.firstLetterUpper(name);

    }

    /**

     * 对Bean的元素进行解析

     */

    public static Object parseObjectElement(Element entry) {

        String beanId = entry.attributeValue("id");

        // 如果已经解析了，那么就不需要再解析

        if (beanFactory.getBean(beanId) != null) {

            return beanFactory.getBean(beanId);

        }

        String beanClass = entry.attributeValue("class");

        Class<?> bean = null;

        try {

            bean = Class.forName(beanClass);

            Object beanObject = bean.newInstance();

            for (Object subEntry : entry.elements("property")) {

                String name = ((Element) subEntry).attributeValue("name");

                String value = ((Element) subEntry).attributeValue("value");

                String dataType = ((Element) subEntry).attributeValue("dataType");

                String ref = ((Element) subEntry).attributeValue("ref");

                if (ref != null) {

                    Object object = beanFactory.getBean(ref); // 从工厂得到object

                    // 如果object没有(有可能定义在后面)，那么解析这个bean

                    if (object == null) {

                        Element element = elementMap.get(ref);

                        Object refObject = parseObjectElement(element);

                        Method method = bean.getMethod(getMethodName(refObject.getClass().getSimpleName()), new Class[]{refObject.getClass()});

                        method.invoke(beanObject, new Object[]{refObject});

                    } else {

                        Method method = bean.getMethod(getMethodName(name), new Class[]{object.getClass()});

                        method.invoke(beanObject, new Object[]{object});

                    }

                    beanFactory.setBean(beanId, beanObject);

                } else {

                    Method method;

                    if (dataType == null) {

                        method = bean.getMethod(getMethodName(name), new Class[]{String.class});

                        method.invoke(beanObject, new Object[]{value});

                    } else if (dataType.equals("int")) {

                        method = bean.getMethod(getMethodName(name), new Class[]{int.class});

                        method.invoke(beanObject, new Object[]{Integer.valueOf(value)});

                    }

                }

            }

            beanFactory.setBean(beanId, beanObject);

            return beanObject;

        } catch (Exception e) {

            e.printStackTrace();

        }

        return null;

    }

}

三、测试的主体类

package com.spring1.main;

import com.spring1.bean.FirstBean;

import com.spring1.bean.SecondBean;

import com.spring1.bean.ThirdBean;

import com.spring1.factory.BeanFactory;

import com.spring1.parse.ParseXmlBean;

import org.junit.Test;

public class MainTest {

    @Test

    public void test_1() {

        BeanFactory beanFactory = ParseXmlBean.parseXmlBean("config/bean.xml");

        FirstBean firstBean = beanFactory.getBean("firstBean", FirstBean.class);

        String userInfo = firstBean.getUserInfo();

        System.out.println(userInfo);

        SecondBean secondBean = (SecondBean) beanFactory.getBean("secondBean");

        String userInfo1 = secondBean.getUserInfo();

        System.out.println(userInfo1);

        ThirdBean thirdBean = (ThirdBean) beanFactory.getBean("thirdBean");

        thirdBean.printUserInfo();

    }

}

四、运行的结果如下

huhx,

liuling,

liuling, , linux

五、定义的xml文件如下：

<beans>

    <bean id="firstBean" class="com.spring1.bean.FirstBean">

        <property name="username" value="huhx"/>

        <property name="password" value="1234"/>

    </bean>

    <bean id="thirdBean" class="com.spring1.bean.ThirdBean">

        <property name="secondBean" ref="secondBean"/>

        <property name="username" value="linux"/>

    </bean>

    <bean id="secondBean" class="com.spring1.bean.SecondBean">

        <property name="age" value="21" dataType="int"/>

        <property name="name" value="liuling"/>

    </bean>

</beans>

友情链接