用Digester解析xml到bean

假设有下列xml文件:

<?xml version='1.0' encoding='utf-8'?>
<address-book>
    <contact myType="individual">
        <name>Zane Pasolini</name>
        <address>999 W. Prince St.</address>
        <city>New York</city>
        <province>NY</province>
        <postalcode>10013</postalcode>
        <country>USA</country>
        <telephone>1-212-345-6789</telephone>
    </contact>
    <contact myType="business">
        <name>SAMOFIX d.o.o.</name>
        <address>Ilica 47-2</address>
        <city>Zagreb</city>
        <province></province>
        <postalcode>10000</postalcode>
        <country from="cn">Croatia</country>
        <telephone>385-1-123-4567</telephone>
    </contact>
</address-book>

 

这是一份常用到的文件，现在我们需要将之映射到java bean,用Digester解析显得非常简单 

public class AddressBookParser
{
    /**
     * Prints the contact information to standard output.
     *
     * @param contact the <code>Contact</code> to print out
     */
    public void addContact(Contact contact)
    {
        System.out.println("TYPE: " + contact.getType());
        System.out.println("NAME: " + contact.getName());
        System.out.println("    ADDRESS:    " + contact.getAddress());
        System.out.println("    CITY:       " + contact.getCity());
        System.out.println("    PROVINCE:   " + contact.getProvince());
        System.out.println("    POSTALCODE: " + contact.getPostalcode());
        System.out.println("    COUNTRY:    " + contact.getCountry());
        System.out.println("    COUNTRY-From:    " + contact.getCountryFrom());
        System.out.println("    TELEPHONE:  " + contact.getTelephone());
    }

    /**
     * Configures Digester rules and actions, parses the XML file specified
     * as the first argument.
     *
     * @param args command line arguments
     */
    public static void main(String[] args) throws IOException, SAXException
    {
        // instantiate Digester and disable XML validation
        Digester digester = new Digester();
        digester.setValidating(false);

        // instantiate AddressBookParser class
        digester.addObjectCreate("address-book", AddressBookParser.class );
        // instantiate Contact class
        digester.addObjectCreate("address-book/contact", Contact.class );

        // set type property of Contact instance when 'type' attribute is found
        //对有属性的值通过setProperties方法

        digester.addSetProperties("address-book/contact",         "myType", "type" );

        // set different properties of Contact instance using specified methods
        //addCallMethod与addBeanPropertySetter等价
        // 参数 0代表一个参数，默认就是当前读的数据

        digester.addCallMethod("address-book/contact/name",       "setName", 0);
        digester.addCallMethod("address-book/contact/address",    "setAddress", 0);
        digester.addCallMethod("address-book/contact/address",    "setAddress",0);
        digester.addCallMethod("address-book/contact/city",       "setCity", 0);
        digester.addCallMethod("address-book/contact/province",   "setProvince", 0);
        digester.addCallMethod("address-book/contact/postalcode", "setPostalcode", 0);
        digester.addCallMethod("address-book/contact/country",    "setCountry", 0);



        //增加country的属性 : from
        digester.addSetProperties("address-book/contact/country","from","countryFrom");
        digester.addCallMethod("address-book/contact/telephone",  "setTelephone", 0);

        // call 'addContact' method when the next 'address-book/contact' pattern is seen
        digester.addSetNext("address-book/contact",               "addContact" );

        // now that rules and actions are configured, start the parsing process
        AddressBookParser abp = (AddressBookParser) digester.parse(new File("c:\\addressbook.xml"));
    }

    /**
     * JavaBean class that holds properties of each Contact entry.
     * It is important that this class be public and static, in order for
     * Digester to be able to instantiate it.
     */
    public static class Contact
    {
        private String type;
        private String name;
        private String address;
        private String city;
        private String province;
        private String postalcode;
        private String country;
        //增加一个country的属性: from
        private String countryFrom;
        private String telephone;

        public void setType(String newType)
        {
            type = newType;
        }
        public String getType()
        {
            return type;
        }

        public void setName(String newName)
        {
            name = newName;
        }
        public String getName()
        {
            return name;
        }

        public void setAddress(String newAddress)
        {
            address = newAddress;
        }
        public String getAddress()
        {
            return address;
        }

        public void setCity(String newCity)
        {
            city = newCity;
        }
        public String getCity()
        {
            return city;
        }

        public void setProvince(String newProvince)
        {
            province = newProvince;
        }
        public String getProvince()
        {
            return province;
        }

        public void setPostalcode(String newPostalcode)
        {
            postalcode = newPostalcode;
        }
        public String getPostalcode()
        {
            return postalcode;
        }

        public void setCountry(String newCountry)
        {
            country = newCountry;
        }
        public String getCountry()
        {
            return country;
        }

        public void setTelephone(String newTelephone)
        {
            telephone = newTelephone;
        }
        public String getTelephone()
        {
            return telephone;
        }

        public String getCountryFrom() {
            return countryFrom;
        }

        public void setCountryFrom(String countryFrom) {
            this.countryFrom = countryFrom;
        }
    }
}

 

 

在 AjaxChat 中的读取房间信息的方式显得更简洁
房间的xml配置文件如下:
 

<rooms>
  <room id="1" name="General Topics" />
  <room id="2" name="Programming" />
  <room id="3" name="Movies" />
  <room id="4" name="Music" />
  <room id="5" name="Television" />
</rooms>

 

解析代码如下 :

public synchronized void init(InputStream isConfigFile) {

        log.debug("init()");
        if (isConfigFile != null) {
            // Read in rooms config and create beans, hand off to DAO.
            Digester digester = new Digester();
            digester.setValidating(false);
            digester.push(this);
            digester.addObjectCreate("rooms/room",
                    "org.apache.struts.apps.ajaxchat.dto.RoomDTO");
            //注意这里，如果xl的属性名称和bean的属性名称完全对应，则直接提供xml的位置即可
            digester.addSetProperties("rooms/room");
            digester.addSetNext("rooms/room", "addRoom");
            try {
                digester.parse(isConfigFile);
                log.info("***** Rooms = " + rooms);
            } catch (IOException ioe) {
                ioe.printStackTrace();
            } catch (SAXException se) {
                se.printStackTrace();
            }
        }

    } // End init().

 

如果在xml文件中增加非attribute则更改后的配置文件如下:

<rooms>
  <room id="1" name="General Topics" />
  <room id="2" name="Programming" />
  <room id="3" name="Movies" />
  <room id="4" name="Music" />
  <room id="5" name="Television" />
  <room>
    <id>6</id>
    <name>shit</name>
  </room>
  <room>
    <id>7</id>
    <name>haha</name>
  </room>
</rooms>

 对应的解析如下:

public synchronized void init(InputStream isConfigFile) {

        log.debug("init()");
        if (isConfigFile != null) {
            // Read in rooms config and create beans, hand off to DAO.
            Digester digester = new Digester();
            digester.setValidating(false);
            digester.push(this);
            digester.addObjectCreate("rooms/room",
                    "org.apache.struts.apps.ajaxchat.dto.RoomDTO");
            digester.addSetProperties("rooms/room");
            //增加addCallMethod方法
            digester.addCallMethod("rooms/room/id","setId",0);
            digester.addCallMethod("rooms/room/name","setName",0);
            digester.addSetNext("rooms/room", "addRoom");
            try {
                digester.parse(isConfigFile);
                log.info("***** Rooms = " + rooms);
            } catch (IOException ioe) {
                ioe.printStackTrace();
            } catch (SAXException se) {
                se.printStackTrace();
            }
        }

    } // End init().

 本文转自http://www.blogjava.net/alex/archive/2006/09/06/68148.html