简单模拟SpringIOC工作机制流程开发

package ioc.factory;

/**
 * Created by zzf on 2016/10/26.
 */
public interface BeanFactory {
    /**
     * 根据对象的ID标识获取对象实例
     * @param name
     * @return
     */
    Object getBean(String name);
}

package ioc.factory;

import ioc.info.BeanInfo;
import ioc.reader.SourceReader;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;

/**
 * Created by zzf on 2016/10/26.
 *
 * 最顶层的IOC实现
 * 该类负责从注册器中取出注册对象
 * 实现从对象描述信息转换为对象实例的过程
 * 实现根据名称获取对象的方法
 *
 */
public abstract class AbstractBeanFactory implements BeanFactory {
    private  String filePath;
    private Map<String,BeanInfo> container;
    protected SourceReader reader;
    public AbstractBeanFactory(String filePath){
        this.filePath=filePath;
        setReader(reader);
    }

    /**
     * 由子类决定如果使用什么样的注册读取器
     * 这里使用了模板方法，父类定义抽象方法，但交给子类自由去设计方法内容
     * @param reader
     */
    protected abstract void setReader(SourceReader reader);


    //注册bean
    public void registerBeans(){
        this.container=this.reader.loadBeans(filePath);
    }

    @Override
    public Object getBean(String name) {
        BeanInfo beanInfo=this.container.get(name);
        if(beanInfo==null){

            return null;

        }else {
            return this.parseBean(beanInfo);
        }

    }

    /**
     * 解析生成并生成对象实例
     * 主要通过反射完成
     * 根据类名，加载指定类，并取得该类的Class对象
     * 使用Class对象实例化该类，获取一个对象。
     * 逐个设置对象字段的值，这里采用setter Method方式
     *
     * @param beanInfo 指定对象的描述信息
     * @return
     */
    protected  Object parseBean(BeanInfo beanInfo){
        Class clazz;
        try {
            //加载Bean的实例
            clazz=Class.forName(beanInfo.getType());
            Object bean=clazz.newInstance();
            
            //获取该对象下的所有方法，包括私有
            Method[] methods=clazz.getDeclaredMethods();
            
            for (String property:beanInfo.getProperties().keySet()){
                String setter="set"+ firstCharToUp(property);
                for(Method method:methods){
                    String methodName=method.getName();
                    
                    if(methodName.equals(setter)){
                        Object value=beanInfo.getProperties().get(property);
                        //使用反射调用set方法
                        method.invoke(bean,value);
                    }
                }
            }
            return bean;

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
            return null;
    }

    private String firstCharToUp(String property) {
        System.out.println(property);
        char [] c=property.toCharArray();
        String first=String.valueOf(c[0]).toUpperCase();
        c[0]=first.charAt(0);
        System.out.println(String.valueOf(c));
        return String.valueOf(c);
    }
}
　　

package ioc.context;

import ioc.factory.AbstractBeanFactory;
import ioc.reader.SourceReader;
import ioc.reader.XMLSourceReader;

/**
 * Created by zzf on 2016/10/26.
 * 上下文的构造方法
 * 该方法中指明注册读取器（这里采用的XML，读者可以根据兴趣去实现另外的方式如注解）
 * 并在构造该方法时一次性加载注册的对象
 */
public class XMLContext extends AbstractBeanFactory{


    public XMLContext(String filePath){
        super(filePath);
        this.setReader(new XMLSourceReader());
        super.registerBeans();
    }

    @Override
    protected void setReader(SourceReader reader) {
        super.reader=reader;
    }
}

package ioc.reader;

import ioc.info.BeanInfo;

import java.util.Map;

/**
 * Created by zzf on 2016/10/26.
 * 注册读取器接口
 * 负责读取用户注册的对象
 * 继承该接口的类可以实现多种读取方式，如从配置文件中读取，根据标注读取，从网络中读取等等
 */
public interface SourceReader {
    Map<String,BeanInfo> loadBeans(String filePath);
}

package ioc.context;

import ioc.factory.AbstractBeanFactory;
import ioc.reader.SourceReader;
import ioc.reader.XMLSourceReader;

/**
 * Created by zzf on 2016/10/26.
 * 上下文的构造方法
 * 该方法中指明注册读取器（这里采用的XML，读者可以根据兴趣去实现另外的方式如注解）
 * 并在构造该方法时一次性加载注册的对象
 */
public class XMLContext extends AbstractBeanFactory{


    public XMLContext(String filePath){
        super(filePath);
        this.setReader(new XMLSourceReader());
        super.registerBeans();
    }

    @Override
    protected void setReader(SourceReader reader) {
        super.reader=reader;
    }
}
package ioc.info;

import java.lang.Object;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by zzf on 2016/10/26.
 */
public class BeanInfo {
    private String id;
    private String type;
    private Map<String,Object> properties=new HashMap<String,Object>();

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public Map<String, Object> getProperties() {
        return properties;
    }

    public void setProperties(Map<String, Object> properties) {
        this.properties = properties;
    }
    public void addProperty(String name, Object object)
    {
        this.properties.put(name, object);
    }
}
 　　

package ioc.reader;

import ioc.info.BeanInfo;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.InputStream;
import java.io.Reader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * Created by zzf on 2016/10/26.
 * 使用 dom4j进行Xml的读取操作
 */
public class XMLSourceReader implements SourceReader {

    @Override
    public Map<String, BeanInfo> loadBeans(String filePath) {
        //读取指定的配置文件
        SAXReader reader = new SAXReader();
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();

        //从class目录下获取指定的xml文件
        InputStream ins = classLoader.getResourceAsStream(filePath);
        Document doc = null;
        try {
            doc = reader.read(ins);
        } catch (DocumentException e) {
            e.printStackTrace();
        }
        //获得根节点
        Element root = doc.getRootElement();
        Map<String,BeanInfo>beanInfoMap=new HashMap<String, BeanInfo>();
        //遍历bean
        for (Iterator i = root.elementIterator("bean"); i.hasNext();){
            Element element = (Element) i.next();
            //获取bean的属性id和class
            Attribute id = element.attribute("id");
            Attribute cls = element.attribute("class");
            try {
                //利用Java反射机制，通过class的名称获取Class对象
                Class bean=Class.forName(cls.getText());
                //获取对应class的信息
                java.beans.BeanInfo info= Introspector.getBeanInfo(bean);
                //获取其属性描述
                PropertyDescriptor [] propertyDescriptors=info.getPropertyDescriptors();
                Method method;
                Object object=bean.newInstance();
                BeanInfo beanInfo=new BeanInfo();
                for(Iterator iterator=element.elementIterator("property");iterator.hasNext();){
                    Element foo2= (Element) iterator.next();
                    //获取该property的name属性
                    Attribute name = foo2.attribute("name");

                    String value = null;
                    //获取该property的子元素value的值
                    for(Iterator ite1 = foo2.elementIterator("value"); ite1.hasNext();) {
                        Element node = (Element) ite1.next();
                        value = node.getText();
                        break;
                    }
                    System.out.println("name:"+name.getText()+"value"+value);
                for (int j=0;j<propertyDescriptors.length;j++){
                    if(propertyDescriptors[j].getName().equalsIgnoreCase(name.getText())){
                        method=propertyDescriptors[j].getWriteMethod();
                        //利用Java的反射极致调用对象的某个set方法，并将值设置进去
                        method.invoke(object,value);
                        //将获取的对象属性信息存入我们自定义的BeanInfo当中
                        beanInfo.addProperty(name.getText(),value);
                }
                }

                    beanInfo.setId(id.getText());
                    beanInfo.setType(cls.getText());
                    beanInfoMap.put(id.getText(),beanInfo);
                }
                return beanInfoMap;
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (IntrospectionException e) {
                e.printStackTrace();
            } catch (InstantiationException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            }
        }

        return null;
    }
}