使用Digester解析XML文件的三种方式小结

<?xml version="1.0" encoding="UTF-8" ?>
<Orders>
    <Order user="张三" date="2008-11-14" price="12279">
    
        <goods id="1">
            <name>IBM笔记本</name>
            <price>8999</price>
            <count>1</count>
            <total_price>8999</total_price>
        </goods>
        
        <goods id="2">
            <name>雅戈尔西服</name>
            <price>1300</price>
            <count>2</count>
            <total_price>2600</total_price>
        </goods>
    
    </Order>
</Orders>

// 订单类
package cn.com.bean;

import java.util.ArrayList;
/**
 * Order.java:订单类
 * @author ypykip
 *
 */
public class Order {
    private String user;    //对应<Order>标签中的user属性
    private String date;    //对应<Order>标签中的date属性
    private String price;   //对应<Order>标签中的price属性
    //对应<Order>标签下的所有<good>标签
    private ArrayList<Goods> goodsList = new ArrayList<Goods>();
    //省略getter和setter...

    // 添加商品到订单
    public void add(Goods goods){
        this.getGoodsList().add(goods);
    }
    // 重写toString()方法，方便于观察结果
    @Override
    public String toString() {
        return "Order [user=" + user + ", date=" + date + ", price=" + price
                + ", goodsList=" + goodsList.toString() + "]";
    }

}
// 商品类
package cn.com.bean;

package cn.com.bean;

/**
 * Goods.java:商品类
 * @author ypykip
 *
 */
public class Goods {
    private String id;
    private String name;
    private String price;
    private String count;
    private String total_price;

    //省略getter和setter...

    @Override
    public String toString() {
        return "Goods [id=" + id + ", name=" + name + ", price=" + price
                + ", count=" + count + ", total_price=" + total_price +"]";
    }
}

// 解析类
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.commons.digester.Digester;
import org.xml.sax.SAXException;

import cn.com.bean.Goods;
import cn.com.bean.Order;

/**
 * title:通过digester的方式来解析Order.xml
 * @author grk
 * 重点：理解栈的概念
 * 当使用addObjectCreate()方法时，创建一个对象进栈
 * 以下的所有操作（有一种情况除外，表明调用的方法）都是对栈顶元素来讲的，除非调用
 * addSetNext()方法，移除栈顶元素并执行次栈顶元素的指定方法
 * 
 * addCallMethod(pattern, methodName):调用栈顶元素的指定方法
 * addCallMethod(pattern, methodName, paramCount):调用栈顶元素的指定方法，可指定方法的
 * 参数个数addCallMethod(pattern, methodName, paramCount, paramTypes):调用栈顶元素的
 * 指定方法，可指定方法的参数个数，类型
 * 
 * addCallParam(pattern, paramIndex):默认设置指定paramIndex参数为标签内容
 * addCallParam(pattern, paramIndex, fromStack):设置指定paramIndex参数为栈顶元素
 * addCallParam(pattern, paramIndex, stackIndex):设置指定paramIndex参数为？
 * addCallParam(pattern, paramIndex, attributeName):设置指定paramIndex参数为标签属性
 * attributeName的值 addObjectParam(pattern, paramIndex, paramObj):设置指定paramIndex
 * 参数为paramObj
 *
 * addSetNext(pattern, methodName):调用次栈顶元素的methodName方法，一般为有一个参数的方法，
 * 将栈顶元素作为入参，如list的add方法
 *  
 */
public class ParseOrder {
    public static void main(String[] args) {
        parseByJavaBean();
    }

    /**
     * 使用javaBean进行存储
     */
    public static void parseByJavaBean(){
        // 1.初始化Digester实例对象
        Digester digester = new Digester();

        // 2.解析<Order>标签节点
        //list进栈，栈顶元素的list对象
        digester.addObjectCreate("Orders", ArrayList.class);
        //Order实例进栈，栈顶元素时Order实例对象
        digester.addObjectCreate("Orders/Order", Order.class);
        //设置<Order>标签的属性
        digester.addSetProperties("Orders/Order");

        // 3.解析<goods>标签节点
        //Goods实例对象进栈
        digester.addObjectCreate("Orders/Order/goods", Goods.class);
        digester.addSetProperties("Orders/Order/goods");
        //设置<goods>下的其他标签内容
        digester.addBeanPropertySetter("Orders/Order/goods/name");
        digester.addBeanPropertySetter("Orders/Order/goods/price");
        digester.addBeanPropertySetter("Orders/Order/goods/count");
        digester.addBeanPropertySetter("Orders/Order/goods/total_price");
        //Goods对象实例出栈
        digester.addSetNext("Orders/Order/goods", "add");
        //Order对象实例出栈
        digester.addSetNext("Orders/Order", "add");

        // 4.加载配置文件
        String filePath = "";
        filePath = System.getProperty("user.dir")+"/bin/config/Order.xml";
        File file = new File(filePath);

        // 5.解析
        try {
            ArrayList list = (ArrayList) digester.parse(file);
            System.out.println(list.toString());
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        }
    }
}

    /**
     * 使用list和map进行存储（过程复杂，不建议使用）
     */
    public static void parseByMap(){
        Digester digester = new Digester();
        // 1.定义Orders节点规则，创建一个List集合
        digester.addObjectCreate("Orders", ArrayList.class);

        // 2.定义Orders/Order节点规则，创建一个Map集合用来存储属性和内容，并将此Map放在上一节点中的List
        digester.addObjectCreate("Orders/Order", HashMap.class);
        digester.addSetNext("Orders/Order", "add");

        // 3.定义Orders/Order节点的属性
        digester.addCallMethod("Orders/Order", "put", 2);//调用栈顶元素map的put方法
        digester.addObjectParam("Orders/Order", 0, "name");//设置key
        digester.addCallParam("Orders/Order", 1, "name");//设置value
        digester.addCallMethod("Orders/Order", "put", 2);
        digester.addObjectParam("Orders/Order", 0, "date");
        digester.addCallParam("Orders/Order", 1, "date");
        digester.addCallMethod("Orders/Order", "put", 2);
        digester.addObjectParam("Orders/Order", 0, "price");
        digester.addCallParam("Orders/Order", 1, "price");

        // 4.定义一个List集合，用来存储Orders/Order节点下的标签
        digester.addCallMethod("Orders/Order", "put", 2);
        digester.addObjectCreate("Orders/Order", ArrayList.class);
        digester.addObjectParam("Orders/Order", 0, "goodsList");
        digester.addCallParam("Orders/Order", 1, true);

        // 5.定义Orders/Order/goods节点规则，分别存储id，name，price，count，total_price属性或标签
        digester.addObjectCreate("Orders/Order/goods", HashMap.class);
        digester.addSetNext("Orders/Order/goods", "add");
        digester.addCallMethod("Orders/Order/goods", "put", 2);
        digester.addObjectParam("Orders/Order/goods", 0, "id");
        digester.addCallParam("Orders/Order/goods", 1, "id");

        digester.addCallMethod("Orders/Order/goods/name", "put", 2);
        digester.addObjectParam("Orders/Order/goods/name", 0, "name");
        digester.addCallParam("Orders/Order/goods/name", 1);
        digester.addCallMethod("Orders/Order/goods/price", "put", 2);
        digester.addObjectParam("Orders/Order/goods/price", 0, "price");
        digester.addCallParam("Orders/Order/goods/price", 1);
        digester.addCallMethod("Orders/Order/goods/count", "put", 2);
        digester.addObjectParam("Orders/Order/goods/count", 0, "count");
        digester.addCallParam("Orders/Order/goods/count", 1);
        digester.addCallMethod("Orders/Order/goods/total_price", "put", 2);
        digester.addObjectParam("Orders/Order/goods/total_price", 0, "total_price");
        digester.addCallParam("Orders/Order/goods/total_price", 1);

        String filePath = System.getProperty("user.dir")+"/bin/config/Order.xml";
        System.out.println(filePath);
        File file = new File(filePath);
        System.out.println(file.getAbsolutePath());
        try {
            ArrayList list = (ArrayList) digester.parse(file);
            System.out.println(list.toString());
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        }
    }

<?xml version="1.0" encoding="UTF-8"?>
<digester-rules>
    <pattern value="Orders">
        <object-create-rule classname="java.util.ArrayList" />  
        <!-- 配置<Order>标签 -->
        <pattern value="Order">
            <object-create-rule classname="cn.com.bean.Order" />
                <set-properties-rule/>

            <!-- 配置<goods>标签 -->
            <pattern value="goods">
                <object-create-rule classname="cn.com.bean.Goods" />
                <set-properties-rule>
                    <alias attr-name="id" prop-name="id" /><!-- id属性对应javabean的id -->
                </set-properties-rule>
                <bean-property-setter-rule pattern="name" propertyname="name" /><!-- name属性对应javabean的name -->
                <bean-property-setter-rule pattern="price" propertyname="price" /><!-- price标签对应javabean的price -->
                <bean-property-setter-rule pattern="count" propertyname="count" /><!-- count标签对应javabean的count -->
                <bean-property-setter-rule pattern="total_price" propertyname="total_price" /><!-- total_price标签对应javabean的total_price -->
                <set-next-rule methodname="add" paramtype="cn.com.bean.Goods"/>

            </pattern>
            <set-next-rule methodname="add" paramtype="cn.com.bean.Order"/>
        </pattern>
    </pattern>
</digester-rules>  

public static void parseByXmlConfig() throws IOException, SAXException, URISyntaxException{
        // 1.加载规则配置文件
        URL rule = Thread.currentThread()
                .getContextClassLoader()
                .getResource("config/OrderConfigRules.xml");

        // 2.加载待解析的配置文件Order.xml
        Reader reader = null;
        try {
            reader = new InputStreamReader(
                    new FileInputStream(
                            new File(System.getProperty("user.dir") + "/bin/config/Order.xml")), "utf-8");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        // 3.根据规则配置文件创建Digester实例对象
        InputSource in = new InputSource(new InputStreamReader(new FileInputStream(new File(rule.toURI()))));
        Digester digester = DigesterLoader.createDigester(in);

        // 4.进行解析并打印结果
        List list = (List) digester.parse(reader);
        System.out.println(list.toString());
        try {
            if(reader != null){
                reader.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }