1DOM解析与SAX解析比较：

DOM解析	SAX解析
原理： 一次性加载xml文档，不适合大容量的文件读取	原理： 加载一点，读取一点，处理一点。适合大容量文件的读取
DOM解析可以任意进行增删改成	SAX解析只能读取
DOM解析任意读取任何位置的数据，甚至往回读	SAX解析只能从上往下，按顺序读取，不能往回读
DOM解析面向对象的编程方法（Node，Element，Attribute）,Java开发者编码比较简单。	SAX解析基于事件的编程方法。java开发编码相对复杂。

2 SAX解析工具：

SAX解析工具-  Sun公司提供的。内置在jdk中。org.xml.sax.*

 

核心的API：

   SAXParser类： 用于读取和解析xml文件对象

parse（ f,  dh）方法： 解析xml文件

 

参数一： File：表示 读取的xml文件。

    参数二： DefaultHandler： SAX事件处理程序。使用DefaultHandler的子类

例如：｛

      1.创建SAXParser对象  

              SAXParser parser=SAXParserFactory.newInstance().newSAXParser();

       2.调用parse方法

　　　　parser.parse(new File("./src/contact.xml"), new MyDefaultHandler());

　　　｝

 

　　3.DefaultHandler类的API:

 

　　　　void startDocument()  :  在读到文档开始时调用

 

　　　　void endDocument()  ：在读到文档结束时调用

 

　　　　void startElement(String uri, String localName, String qName, Attributes attributes)  ：读到开始标　　　　签时调用

 

　　　　void endElement(String uri, String localName, String qName)   ：读到结束标签时调用

 

　　　　void characters(char[] ch, int start, int length)  ： 读到文本内容时调用

3.SAM解析练习：

　　1.基本练习，查看函数调用；

　　SamExercise.java：

package com.dom4j.SAM;import java.io.File;import javax.xml.parsers.ParserConfigurationException;import javax.xml.parsers.SAXParser;import javax.xml.parsers.SAXParserFactory;import org.xml.sax.SAXException;public class SamExercise {    public static void main(String[] args) throws Exception, SAXException {        SAXParser parser = SAXParserFactory.newInstance().newSAXParser();        parser.parse(new File("./src/contact.xml"), new MyDefalutHandler());    }}

 

　　MyDefalutHandler.java：

package com.dom4j.SAM;import javax.xml.stream.events.StartDocument;import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;public class MyDefalutHandler extends DefaultHandler{    @Override    public void startDocument() throws SAXException {        System.out.println("MyDefalutHandler.startDocument()");    }        @Override    public void startElement(String uri, String localName, String qName,            Attributes attributes) throws SAXException {        System.out.println("MyDefalutHandler.startElement()->>>" + qName);    }        @Override    public void characters(char[] ch, int start, int length)            throws SAXException {        System.out.println("MyDefalutHandler.characters()->>>" + new String(ch, start, length));    }        @Override    public void endElement(String uri, String localName, String qName)            throws SAXException {        System.out.println("MyDefalutHandler.endElement()->>>" + qName);    }        @Override    public void endDocument() throws SAXException {        System.out.println("MyDefalutHandler.endDocument()");    }}

　　2.读取打印出来xml文件：

　　contact.xml:

      
          
               
        
         张三
                
        
         20
                
        
         134222223333
                
        
         zhangsan@qq.com
                
        
         432221111
            
           
               
        
         lisi
                
        
         20
                
        
         134222225555
                
        
         lisi@qq.com
                
        
         432222222
            
           
       
      

　　DisplayAllContent.java:

package com.dom4j.SAM;import java.io.File;import javax.xml.parsers.ParserConfigurationException;import javax.xml.parsers.SAXParser;import javax.xml.parsers.SAXParserFactory;import org.xml.sax.SAXException;public class DisplayAllContent {    public static void main(String[] args) throws Exception, SAXException {        SAXParser parser = SAXParserFactory.newInstance().newSAXParser();        MyDisplayAllContentHandle handle = new MyDisplayAllContentHandle();        parser.parse(new File("./src/contact.xml"), handle);        System.out.println(handle.getContent());    }}

　　MyDisplayAllContentHandle:

package com.dom4j.SAM;import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;public class MyDisplayAllContentHandle extends DefaultHandler {    private static StringBuffer sb;    static{        sb = new StringBuffer();    }    public String getContent(){        return sb.toString();    }    @Override    public void startElement(String uri, String localName, String qName,            Attributes attributes) throws SAXException {        sb.append("<");        sb.append(qName);        for(int i = 0; i < attributes.getLength(); i++){            sb.append(" " + attributes.getQName(i));            sb.append("=" + "\"" + attributes.getValue(i) + "\"");        }        sb.append(">");    }        @Override    public void characters(char[] ch, int start, int length)            throws SAXException {        sb.append(new String(ch, start, length));    }        @Override    public void endElement(String uri, String localName, String qName)            throws SAXException {        sb.append("
      ");    }}

 

　　3.将xml文件内容放在一个类中，并输出：

　　contact.java:

package com.dom4j.SAM;public class contact {    private String id;    private String name;    private String age;    private String qq;    private String email;    private String phone;    public String getId() {        return id;    }    public void setId(String id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getAge() {        return age;    }    public void setAge(String age) {        this.age = age;    }    public String getqq() {        return qq;    }    public void setqq(String qq) {        this.qq = qq;    }    public String getemail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }    public String getPhone() {        return phone;    }    public void setPhone(String phone) {        this.phone = phone;    }    @Override    public String toString() {        return "Person \n id=" + id + ", name=" + name + ", age=" + age + ", qq=" + qq                + ", email=" + email + ", phone=" + phone + "\n";    }    }

　　ReadValue.java:

package com.dom4j.SAM;import java.io.File;import java.util.ArrayList;import javax.xml.parsers.SAXParser;import javax.xml.parsers.SAXParserFactory;import org.xml.sax.SAXException;public class ReadValue{        public static void main(String[] args) throws Exception, SAXException {        SAXParser parser = SAXParserFactory.newInstance().newSAXParser();        MyReadValueHandle handle = new MyReadValueHandle();        parser.parse(new File("./src/contact.xml"), handle);        ArrayList
      
        list = handle.getList();        for(contact acontact : list){            System.out.println(acontact);        }    }}
      

　　MyReadValueHandle.java:

package com.dom4j.SAM;import java.util.ArrayList;import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;public class MyReadValueHandle extends DefaultHandler {        private ArrayList
      
        list = new ArrayList
       
        ();    private contact acontact;    private String curTag;        public ArrayList
        
          getList(){        return list;    }        @Override    public void startElement(String uri, String localName, String qName,            Attributes attributes) throws SAXException {        curTag = qName;        if(qName.equals("contact")){            acontact = new contact();            acontact.setId(attributes.getValue("id"));        }    }        @Override    public void characters(char[] ch, int start, int length)            throws SAXException {        String content = new String(ch, start, length);        if("name".equals(curTag)){            acontact.setName(content);        }        if("age".equals(curTag)){            acontact.setAge(content);        }        if("phone".equals(curTag)){            acontact.setPhone(content);        }        if("email".equals(curTag)){            acontact.setEmail(content);        }        if("qq".equals(curTag)){            acontact.setqq(content);        }    }        @Override    public void endElement(String uri, String localName, String qName)            throws SAXException {        curTag = null;//注意！！避免换行空格的影响        if(qName.equals("contact")){            list.add(acontact);        }    }}
        
       
      

　　4.设计一个通讯录程序

　　联系人： 编号  姓名  性别  年龄  电话  QQ 邮箱

　　功能要求：

　　　　添加联系人

　　　　修改联系人

　　　　删除联系人

　　　　查询所有联系人

　　思路：添加联系人的时候先把输入的内容放在一个配置文件中config.txt，然后用BeanUtil框架从这个配置文件中读取内容用dom解析，放到contact.xml中，修改的时候直接用xpath技术得到id，通过dom解析修改xml中的内容，删除和修改类同，查询的时候直接用的SAX解析；

　　代码:

main.java

package com.dom4j.contacts;import java.util.Scanner;public class Main {    public static void main(String[] args) throws Exception {        Scanner cin = new Scanner(System.in);        String operate;        while(true){            System.out.println("================");            System.out.println("【1】添加联系人");            System.out.println("【2】修改联系人");            System.out.println("【3】删除联系人");            System.out.println("【4】查询所有联系人");            System.out.println("【Q】退出程序");            System.out.println("==================");            operate = cin.nextLine();            if(operate.equals("Q")){                break;            }            if(operate.equals("1")){                new AlterContact().addContact();            }            if(operate.equals("2")){                new AlterContact().alterContact();            }            if(operate.equals("3")){                new AlterContact().deleteContact();            }            if(operate.equals("4")){                new QueryContact().display();            }                    }    }}

contact.java:

package com.dom4j.contacts;public class Contact {    private String id, name, sex, phone, qq, email;    private String age;    public String getId() {        return id;    }    public void setId(String id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getSex() {        return sex;    }    public void setSex(String sex) {        this.sex = sex;    }    public String getAge() {        return age;    }    public void setAge(String age) {        this.age = age;    }    @Override    public String toString() {        return id + "\t" + name + "\t" + age + "\t" + sex                + "\t" + phone + "\t" + qq + "\t" + email;    }    public String getPhone() {        return phone;    }    public void setPhone(String phone) {        this.phone = phone;    }    public String getQq() {        return qq;    }    public void setQq(String qq) {        this.qq = qq;    }    public String getEmail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }    }

AlterContact.java:

package com.dom4j.contacts;import java.io.BufferedWriter;import java.io.File;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.util.List;import java.util.Properties;import java.util.Scanner;import org.apache.commons.beanutils.BeanUtils;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.DocumentHelper;import org.dom4j.Element;import org.dom4j.ElementHandler;import org.dom4j.io.OutputFormat;import org.dom4j.io.SAXReader;import org.dom4j.io.XMLWriter;import org.xml.sax.DocumentHandler;import sun.font.CreatedFontTracker;public class AlterContact {    private Scanner cin = new Scanner(System.in);    private static Contact contact;    private Properties properties;        static{        contact = new Contact();    }        public void addContact() throws Exception {        WriteFile();        //读取配置文件        properties = new Properties();        Class clazz = AlterContact.class;        InputStream inputStream = clazz.getResourceAsStream("/config.txt");        //注意这个文件在bin目录下的，并不在src下，错了半天才发现！！！        try {            properties.load(inputStream);        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        //向配置文件中读取数据加入xml文件中        Document doc = new SAXReader().read("./src/contact.xml");        List nodes = doc.selectNodes("//contactList");        Element list = (Element)nodes.get(0);        Element newContact = list.addElement("contact");        newContact.addAttribute("id", properties.getProperty("id"));        newContact.addElement("age").setText(properties.getProperty("age"));        newContact.addElement("name").setText(properties.getProperty("name"));        newContact.addElement("sex").setText(properties.getProperty("sex"));        newContact.addElement("phone").setText(properties.getProperty("phone"));        newContact.addElement("qq").setText(properties.getProperty("qq"));        newContact.addElement("email").setText(properties.getProperty("email"));        //写入xml文件        OutputFormat format = OutputFormat.createPrettyPrint();        FileOutputStream outputStream = new FileOutputStream(new File("./src/contact.xml"));        format.setEncoding("utf-8");        XMLWriter writer = new XMLWriter(outputStream, format);        writer.write(doc);        writer.close();        System.out.println("添加成功！");    }    public void alterContact() throws Exception {        System.out.println("请输入您要修改的联系人的编号：");        String id = cin.nextLine();        Document doc = new SAXReader().read(new File("./src/contact.xml"));        List list = doc.selectNodes("//contact[@id=" + id + "]");        if(list.size() == 0){            System.out.println("您要修改 的id不存在！");            return;        }        Element acontact = (Element) list.get(0);        System.out.println("您要修改的联系人信息为：");        System.out.println("name: " + acontact.element("name").getText());        System.out.println("sex: " + acontact.element("sex").getText());        System.out.println("age: " + acontact.element("age").getText());        System.out.println("phone: " + acontact.element("phone").getText());        System.out.println("qq: " + acontact.element("qq").getText());        System.out.println("email: " + acontact.element("email").getText());                while(true){            System.out.println("欢迎来到修改系统\t如需退出请按Q键");            System.out.println("请输入您要修改的项目：");            String op = cin.nextLine();            if(op.equals("Q")){                return;            }            System.out.println("请输入修改的内容：");            String va = cin.nextLine();            acontact.element(op).setText(va);            //写入xml文件            OutputFormat format = OutputFormat.createPrettyPrint();            FileOutputStream outputStream = new FileOutputStream(new File("./src/contact.xml"));            format.setEncoding("utf-8");            XMLWriter writer = new XMLWriter(outputStream, format);            writer.write(doc);            writer.close();            System.out.println("修改成功！");        }            }    public void deleteContact() throws Exception {        System.out.println("请输入您要删除的联系人编号：");        String id = cin.nextLine();        Document doc = new SAXReader().read(new File("./src/contact.xml"));        List
      
        list = (List
       
        )doc.selectNodes("//contact[@id=" + id + "]");        if(list.size() == 0){            System.out.println("您要删除的联系人不存在！");            return;        }        for(Element contact : list){            contact.detach();        }        //写入xml文件                OutputFormat format = new OutputFormat().createPrettyPrint();        FileOutputStream out = new FileOutputStream(new File("./src/contact.xml"));        format.setEncoding("utf-8");        XMLWriter writer = new XMLWriter(out, format);        writer.write(doc);        writer.close();        System.out.println("删除成功! ");    }        private void WriteFile() throws Exception{        BufferedWriter writer = new BufferedWriter(new FileWriter("./bin/config.txt"));        //向配置文件中写数据放入对象中        System.out.println("请输入编号：");        String str = cin.nextLine();        writer.write("id=" + str);        BeanUtils.setProperty(contact, "id", str);        writer.newLine();                System.out.println("请输入姓名：");        str = cin.nextLine();        BeanUtils.setProperty(contact, "name", str);        writer.write("name=" + str);        writer.newLine();                System.out.println("请输入性别：");        str = cin.nextLine();        BeanUtils.setProperty(contact, "sex", str);        writer.write("sex=" + str);        writer.newLine();                System.out.println("请输入年龄：");        str = cin.nextLine();        BeanUtils.setProperty(contact, "age", str);        writer.write("age=" + str);        writer.newLine();                System.out.println("请输入电话号码：");        str = cin.nextLine();        BeanUtils.setProperty(contact, "phone", str);        writer.write("phone=" + str);        writer.newLine();                System.out.println("请输入qq：");        str = cin.nextLine();        BeanUtils.setProperty(contact, "qq", str);        writer.write("qq=" + str);        writer.newLine();                System.out.println("请输入email：");        str = cin.nextLine();        BeanUtils.setProperty(contact, "email", str);        writer.write("email=" + str);        writer.newLine();        writer.close();    }}
       
      

queryContact.java:

package com.dom4j.contacts;import java.io.File;import java.util.ArrayList;import javax.xml.parsers.ParserConfigurationException;import javax.xml.parsers.SAXParser;import javax.xml.parsers.SAXParserFactory;import org.dom4j.io.SAXReader;import org.xml.sax.SAXException;import com.dom4j.SAM.MyDefalutHandler;public class QueryContact {    private ArrayList
      
       list;        public void display() throws Exception, SAXException{        SAXParser parser = SAXParserFactory.newInstance().newSAXParser();        MyQueryHandler dh = new MyQueryHandler();        parser.parse(new File("./src/contact.xml"), dh);        list = dh.getList();        System.out.println("id\tname\tage\tsex\tphone\t\tqq\t\temail\t\t");        for(int i = 0; i < list.size(); i++){            System.out.println(list.get(i));        }    }    }
      

MyQueryContact.java:

package com.dom4j.contacts;import java.util.ArrayList;import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;import com.sun.org.apache.xalan.internal.xsltc.compiler.Parser;public class MyQueryHandler extends DefaultHandler {    private ArrayList
      
       list = new ArrayList
       
        ();    private String tag;    private Contact contact;    public ArrayList
        
          getList(){        return list;    }    @Override    public void startElement(String uri, String localName, String qName,            Attributes attributes) throws SAXException {        tag = qName;        if("contact".equals(qName)){            contact = new Contact();            contact.setId(attributes.getValue("id"));        }    }        @Override    public void characters(char[] ch, int start, int length)            throws SAXException {        String content = new String(ch, start, length);        if("id".equals(tag)){            contact.setId(content);        }        if("name".equals(tag)){            contact.setName(content);        }        if("age".equals(tag)){            contact.setAge(content);        }        if("sex".equals(tag)){            contact.setSex(content);        }        if("qq".equals(tag)){            contact.setQq(content);        }        if("phone".equals(tag)){            contact.setPhone(content);        }        if("email".equals(tag)){            contact.setEmail(content);        }    }        @Override    public void endElement(String uri, String localName, String qName)            throws SAXException {        tag = null;        if("contact".equals(qName)){            list.add(contact);        }    }}