xml建模

1.XML的由来

1.就是将指定的xml字符串当作对象来操作.

2.如果说当对一个指定的xml格式字符串完成了建模操作.

3.好处:只需要调用指定的方法就可以完成预定的字符串获取.

2.建模的思路

1、分析需要被建模的文件中有那几个对象

2、每个对象拥有的行为以及属性

3、定义对象从小到大（从里到外）

4、通过23种的设计模式中的工厂模式，解析xml生产出指定对象

5.好处:提高代码的复用性

3.应用

在XML建模中用几个类来获取哦 config.xml中的属性

属性为String类型，子元素标签则是map的值，子元素标签的唯一标识则为map的值

先定义xml模型对象（ForwardModel，ActionModel，ConfigModel  ）

public class ForwardModel {
    // <forward name="failed" path="/reg.jsp" redirect="false" />
    private String name;
    private String path;
    private boolean redirect;

    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 String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}
import java.util.HashMap;
import java.util.Map;

public class ActionModel {
    // <action path="/regAction" type="test.RegAction">
    private String path;
    private String type;
    private Map<String, ForwardModel> forMap = new HashMap<>();

    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;
    }

    public void push(ForwardModel forwardModel) {
        forMap.put(forwardModel.getName(), forwardModel);
    }

    public ForwardModel pop(String name) {
        return forMap.get(name);
    }

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

public class ConfigModel {

    private Map<String, ActionModel> aMap = new HashMap<>();

    //存
    public void push(ActionModel actionModel) {
        aMap.put(actionModel.getPath(), actionModel);
    }
    
    //取
    public ActionModel pop(String path) {
        return aMap.get(path);
    } 

    
    
}

最后通过工厂模式，解析XML生产的指定对象

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

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

/**
 * 23种设计模式
 *  设计模式是一种解决方案，就是为了处理java中遇到的特定的一些问题
 *   工厂模式 
 *       解决什么问题呢？
 *   它是用来将资源文件生产指定的实体类 好处：
 *   提高了代码的复用性
 */
public class ConfigModelFactory {

    public static ConfigModel build() throws DocumentException {
        return configModel("config.xml");
    }

    /**
     * 生产出有内容的实体类ConfigModel
     * 
     * @param string
     * @return
     * @throws DocumentException
     */
     public static ConfigModel  configModel(String xmlPath) throws DocumentException {
            ConfigModel configModel=new ConfigModel();
            ActionModel actionModel=null;
            ForwardModel forwardModel=null;
            InputStream in=ConfigModelFactory.class.getResourceAsStream(xmlPath);
            SAXReader sax=new SAXReader();
            Document doc=sax.read(in);
             List<Element>  actionEles= doc.selectNodes("/config/action");
             for (Element actionEle : actionEles) {
                actionModel=new ActionModel();
                //给actionModel对象填充xml中的action标签的内容
                actionModel.setPath(actionEle.attributeValue("path"));
                actionModel.setType(actionEle.attributeValue("type"));
                 
                List<Element>  forwardEles=actionEle.selectNodes("forward");
                for (Element forwardEle : forwardEles) {
                    forwardModel=new ForwardModel();
                    //给forwardModel对象填充xml中的forward标签的内容
                    forwardModel.setName(forwardEle.attributeValue("name"));
                    forwardModel.setPath(forwardEle.attributeValue("path"));
                    forwardModel.setRedirect(!"false".equals(forwardEle.attributeValue(("redirect"))));
//                  <forward name="failed" path="/reg.jsp" redirect="false" />
                //  redirect默认是true 重定向  只有填了false才是转发
                //forwardEle.attributeValue(("redirect"))拿到的是xml中你所填的值
                //  不填  重定向  "false".equals(forwardEle.attributeValue(("redirect")))是false
                //  填 true   重定向 "false".equals(forwardEle.attributeValue(("redirect")))是false
                //  填flase 转发 "false".equals(forwardEle.attributeValue(("redirect")))是true;
                    actionModel.push(forwardModel);
                }
                configModel.push(actionModel);
            }
            return configModel;
        }

    public static void main(String[] args) throws DocumentException {
        ConfigModel configModel = ConfigModelFactory.build();
        ActionModel actionModel = configModel.pop("/loginAction");
//        System.out.println(actionModel.getType());
        ForwardModel forwardModel=actionModel.pop("success");
        System.out.println(actionModel.getType());
        System.out.println(forwardModel.getPath());
    }
}

 作业：

public class ServletClassModel {
    private String context;

    public String getContext() {
        return context;
    }

    public void setContext(String context) {
        this.context = context;
    }
}
import java.util.ArrayList;
import java.util.List;

public class ServletMappingModel {
    private ServletNameModel servletNameModel;
    private List<UrlPatternModel> urlPatternModels = new ArrayList<>();
    public ServletNameModel getServletNameModel() {
        return servletNameModel;
    }
    public void setServletNameModel(ServletNameModel servletNameModel) {
        this.servletNameModel = servletNameModel;
    }
    
    public void pushUrlPatternModel(UrlPatternModel urlPatternModel) {
        urlPatternModels.add(urlPatternModel);
    }
    
    public List<UrlPatternModel> getUrlPatternModels() {
        return urlPatternModels;
    }
}
public class ServletModel {
    private ServletNameModel servletNameModel;
    private ServletClassModel servletClassModel;

    public ServletNameModel getServletNameModel() {
        return servletNameModel;
    }

    public void setServletNameModel(ServletNameModel servletNameModel) {
        this.servletNameModel = servletNameModel;
    }

    public ServletClassModel getServletClassModel() {
        return servletClassModel;
    }

    public void setServletClassModel(ServletClassModel servletClassModel) {
        this.servletClassModel = servletClassModel;
    }

}
public class ServletNameModel {
    private String context;

    public String getContext() {
        return context;
    }

    public void setContext(String context) {
        this.context = context;
    }
}
public class UrlPatternModel {
    private String context;

    public String getContext() {
        return context;
    }

    public void setContext(String context) {
        this.context = context;
    }

}
import java.util.ArrayList;
import java.util.List;

public class WebAppModel {
    private List<ServletModel> servletModels = new ArrayList<>();
    private List<ServletMappingModel> servletMappingModels = new ArrayList<>();

    public void pushServletModel(ServletModel servletModel) {
        servletModels.add(servletModel);
    }
    
    public List<ServletModel> getServletModels() {
        return servletModels;
    }
    
    public void pushServletMappingModel(ServletMappingModel servletMappingModel) {
        servletMappingModels.add(servletMappingModel);
    }
    
    public List<ServletMappingModel> getServletMappingModels() {
        return servletMappingModels;
    }

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

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

public class WebAppModelFactory {
    public static WebAppModel buildWebAppModel() {
        //xml根目录下
        String xmlPath = "/web.xml";
        return buildWebAppModel(xmlPath);
    }

    /**
     * 建模
     * 
     * @param xmlPath
     * @return
     */
    public static WebAppModel buildWebAppModel(String xmlPath) {
        InputStream in = WebAppModelFactory.class.getResourceAsStream(xmlPath);
        SAXReader saxReader = new SAXReader();
        WebAppModel webAppModel = new WebAppModel();
        try {
            Document doc = saxReader.read(in);
            /*
             * 将servlet的标签内容填充进WebApp
             */
            List<Element> servletEles = doc.selectNodes("/web-app/servlet");
            for (Element servletEle : servletEles) {
                ServletModel servletModel = new ServletModel();

                /*
                 * 给ServletModel填充xml的内容
                 */
                Element servletNameEle = (Element) servletEle.selectSingleNode("servlet-name");
                Element servletClassEle = (Element) servletEle.selectSingleNode("servlet-class");
                ServletNameModel servletNameModel = new ServletNameModel();
                ServletClassModel servletClassModel = new ServletClassModel();
                servletNameModel.setContext(servletNameEle.getText());
                servletClassModel.setContext(servletClassEle.getText());

                servletModel.setServletNameModel(servletNameModel);
                servletModel.setServletClassModel(servletClassModel);

                webAppModel.pushServletModel(servletModel);
            }

            /*
             * 将servlet-mapping的标签内容填充进WebApp
             */
            List<Element> servletMappingEles = doc.selectNodes("/web-app/servlet-mapping");
            for (Element servletMappingEle : servletMappingEles) {
                ServletMappingModel servletMappingModel = new ServletMappingModel();

                /*
                 * 给ServletMappingModel填充xml的内容
                 */
                Element servletNameEle = (Element) servletMappingEle.selectSingleNode("servlet-name");
                ServletNameModel servletNameModel = new ServletNameModel();
                servletNameModel.setContext(servletNameEle.getText());
                servletMappingModel.setServletNameModel(servletNameModel);

                List<Element> urlPatternEles = servletMappingEle.selectNodes("url-pattern");
                for (Element urlPatternEle : urlPatternEles) {
                    UrlPatternModel urlPatternModel = new UrlPatternModel();
                    urlPatternModel.setContext(urlPatternEle.getText());
                    servletMappingModel.pushUrlPatternModel(urlPatternModel);
                }

                webAppModel.pushServletMappingModel(servletMappingModel);
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return webAppModel;
    }

    /**
     * 通过浏览器输入的网址自动找到对应的后台处理类
     * 
     * @param webAppModel
     *            建模后的实体类
     * @param url
     *            浏览器访问的网址
     * @return
     */
    public static String getServletClassByUrl(WebAppModel webAppModel, String url) {
        String servletClass = "";
        /*
         * 找到浏览器网址对应的servlet-name
         */
        String servletName = "";
        List<ServletMappingModel> servletMappingModels = webAppModel.getServletMappingModels();
        for (ServletMappingModel servletMappingModel : servletMappingModels) {
            List<UrlPatternModel> urlPatternModels = servletMappingModel.getUrlPatternModels();
            for (UrlPatternModel urlPatternModel : urlPatternModels) {
                if (url.equals(urlPatternModel.getContext())) {
                    ServletNameModel servletNameModel = servletMappingModel.getServletNameModel();
                    servletName = servletNameModel.getContext();
                }
            }
        }

        /*
         * 找到servlet-name对应的后台处理类
         */
        List<ServletModel> servletModels = webAppModel.getServletModels();
        for (ServletModel servletModel : servletModels) {
            ServletNameModel servletNameModel = servletModel.getServletNameModel();
            if (servletName.equals(servletNameModel.getContext())) {
                ServletClassModel servletClassModel = servletModel.getServletClassModel();
                servletClass = servletClassModel.getContext();
            }
        }
        return servletClass;
    }

    public static void main(String[] args) {
        WebAppModel webAppModel = WebAppModelFactory.buildWebAppModel();
        String res = getServletClassByUrl(webAppModel, "/jrebelServlet");
        String res2 = getServletClassByUrl(webAppModel, "/jrebelServlet2");
        String res3 = getServletClassByUrl(webAppModel, "/jrebelServlet3");
        System.out.println(res);
        System.out.println(res2);
        System.out.println(res3);

    }
}

xml文件放置在根目录下(src文件)

<?xml version="1.0" encoding="UTF-8"?>
<web-app>


    <servlet>

        <servlet-name>jrebelServlet</servlet-name>

        <servlet-class>com.zking.xml.JrebelServlet</servlet-class>

    </servlet>


    <servlet-mapping>

        <servlet-name>jrebelServlet</servlet-name>

        <url-pattern>/jrebelServlet</url-pattern>

    </servlet-mapping>


    <servlet>

        <servlet-name>jrebelServlet2</servlet-name>

        <servlet-class>com.zking.xml.JrebelServlet2</servlet-class>

    </servlet>


    <servlet-mapping>

        <servlet-name>jrebelServlet2</servlet-name>

        <url-pattern>/jrebelServlet2</url-pattern>

        <url-pattern>/jrebelServlet3</url-pattern>

    </servlet-mapping>

</web-app>
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原文地址：https://www.cnblogs.com/huxiaocong/p/11015593.html