JEE.XML建模

XML建模介绍

我们为什么要进行建模呢？

我们可以通过获取资源文件xml，拿到指定的xml字符串，那么不同的人，有不同的需求，那就意味着每一个人都需要对指定的xml文件进行解析，这样我们耗费的时间将大大增加，所以我们要将xml字符串存储到内存当中方便拿取，这就是我们为什么要进行一个建模的操作

建模说白了就是将指定的xml字符串当作对象来操作

如果一个xml文件完成了建模，那么我们就可以调用指定的方法直接拿到数据，不需要再走一遍io流的操作，节省了大部分时间

建模的思路：

1. 分析需要被建模的文件中有哪几个对象
2. 每个对象拥有的行为和属性
3. 定义对象从小到大（从里到外）
4. 通过工厂模式，解析xml生产出指定对象（提高代码的复用性）

建模分两步：

1. 以面向对象的编程思路，描述xml资源文件
2. 将xml文件中的内容封装进model实体对象

首先，我们需要导入jar包

实例

config.xml

DOCTYPE config[
	<!ELEMENT config (action*)>
	<!ELEMENT action (forward*)>
	<!ELEMENT forward EMPTY>
	<!ATTLIST action
	  path CDATA #REQUIRED
	  type CDATA #REQUIRED
	>
	<!ATTLIST forward
	  name CDATA #REQUIRED
	  path CDATA #REQUIRED
	  redirect (true|false) "false"
	>
]>
<config>
	<action path="/studentAction" type="org.lisen.mvc.action.StudentAction">
		<forward name="students" path="/students/studentList.jsp" redirect="false"/>
	action>
	<action path="/studentAction02" type="org.lisen.mvc.action.StudentAction">
		<forward name="students02" path="/students/studentList.jsp" redirect="false"/>
	action>
config>

ForwardModel.java

package com.mymvc;

public class ForwardModel {

	private String name;
	private String path;
	private boolean redirect;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public boolean isRedirect() {
		return redirect;
	}

	public void setRedirect(boolean redirect) {
		this.redirect = redirect;
	}

	public void setRedirect(String redirect) {
		this.redirect = Boolean.valueOf(redirect);
	}

	@Override
	public String toString() {
		return "ForwardModel [name=" + name + ", path=" + path + ", redirect=" + redirect + "]";
	}

}

ForwardDuplicateDefinitionException.java

package com.mymvc;

public class ForwardDuplicateDefinitionException extends RuntimeException {

	public ForwardDuplicateDefinitionException() {
		super();
	}
	
	public ForwardDuplicateDefinitionException(String msg) {
		super(msg);
	}
	
	/**
	 * @param msg
	 * @param c(异常原因)
	 */
	public ForwardDuplicateDefinitionException(String msg ,Throwable c) {
		super(msg ,c);
	}
	
}

ForwardNotFoundException.java

package com.mymvc;

public class ForwardNotFoundException extends RuntimeException{

	public ForwardNotFoundException() {
		super();
	}
	
	public ForwardNotFoundException(String msg) {
		super(msg);
	}
	
	/**
	 * @param msg
	 * @param c(异常原因)
	 */
	public ForwardNotFoundException(String msg ,Throwable c) {
		super(msg ,c);
	}
	
}

ActionModel.java

package com.mymvc;

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

public class ActionModel {

	private String path;
	private String type;
	private Map<String, ForwardModel> forwardMap = new HashMap<String, ForwardModel>();

	public void put(ForwardModel forward) {
		if(forwardMap.containsKey(forward.getName())) {
			throw new ForwardDuplicateDefinitionException("forward name="+forward.getName()+" duplicate definition");
		}
		forwardMap.put(forward.getName(), forward);
	}
	
	public ForwardModel find(String name) {
		if(!forwardMap.containsKey(name)) {
			throw new ForwardNotFoundException("forward name="+name+" not found");
		}
		return forwardMap.get(name);
	}

	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public String getType() {
		return type;
	}

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

	@Override
	public String toString() {
		return "ActionModel [path=" + path + ", type=" + type + "]";
	}

}

ActionDuplicateDefinitionException.java

package com.mymvc;

public class ActionDuplicateDefinitionException extends RuntimeException {

	public ActionDuplicateDefinitionException() {
		super();
	}
	
	public ActionDuplicateDefinitionException(String msg) {
		super(msg);
	}
	
	/**
	 * @param msg
	 * @param c(异常原因)
	 */
	public ActionDuplicateDefinitionException(String msg ,Throwable c) {
		super(msg ,c);
	}
	
}

ActionNotFoundException.java

package com.mymvc;

public class ActionNotFoundException extends RuntimeException{

	public ActionNotFoundException() {
		super();
	}
	
	public ActionNotFoundException(String msg) {
		super(msg);
	}
	
	/**
	 * @param msg
	 * @param c(异常原因)
	 */
	public ActionNotFoundException(String msg ,Throwable c) {
		super(msg ,c);
	}
	
}

ConfigModel.java

package com.mymvc;

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

public class ConfigModel {

	private Map<String ,ActionModel> actionMap = new HashMap<String ,ActionModel>();
	
	public void put(ActionModel action) {
		if(actionMap.containsKey(action.getPath())) {
			throw new ActionDuplicateDefinitionException("action path="+action.getPath()+" duplicate definition");
		}
		actionMap.put(action.getPath(), action);
	}
	
	public ActionModel find(String path) {
		if(!actionMap.containsKey(path)) {
			throw new ActionNotFoundException("action path="+path+" not found");
		}
		return actionMap.get(path);
	}
	
}

ConfigModelFactory.java

package com.mymvc;

import java.io.InputStream;
import java.util.List;

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

public class ConfigModelFactory {


	/**
	 * 单例模式
	 */
	private ConfigModelFactory() {}
	
	private static ConfigModel config = new ConfigModel();
	
	/**
	 * 使用单例模式获得ConfigModel
	 * @return ConfigModel 
	 */
	public static ConfigModel getConfig() {
		return config;
	}
	
	static {
		try {
			InputStream in = ConfigModelFactory.class.getResourceAsStream("/config.xml");
			SAXReader reader = new SAXReader();
			Document doc = reader.read(in);
			Element root = doc.getRootElement();
			List<Element> actions = root.selectNodes("action");
			for (Element e : actions) {
				String path = e.attributeValue("path");
				String type = e.attributeValue("type");
				ActionModel action = new ActionModel();
				action.setPath(path);
				action.setType(type);
				List<Element> forwards = e.selectNodes("forward");
				for (Element fe : forwards) {
					String name = fe.attributeValue("name");
					String fpath = fe.attributeValue("path");
					String redirect = fe.attributeValue("redirect");
					ForwardModel forward = new ForwardModel();
					forward.setName(name);
					forward.setPath(path);
					forward.setRedirect(redirect);
					action.put(forward);
				}
				config.put(action);
			}
		}catch (Exception e) {
			e.printStackTrace();
		}
	}
	public static void main(String[] args) {
		ActionModel actionModel = ConfigModelFactory.getConfig().find("/studentAction");
		System.out.println(actionModel);
		System.out.println(actionModel.find("students"));
	}
}