SAX解析xml

1.创建事件处理程序（编写ContentHandler的实现类，一般集成自DefaultHandler类，采用 adapter 模式）
2.创建SAX解析器
3.将事件处理程序分配到解析器
4.对文档进行解析，将每个事件发送给事件处理程序

XMl文档

 1 <?xml version = "1.0" encoding = "UTF-8"?>
 2 <books>
 3     <book bookno="001">
 4         <title> java 编程</title>
 5         <author> me </author>
 6         <price> 80 </price>
 7     </book>
 8     <book bookno="002">
 9         <title> android 编程</title>
10         <author> me </author>
11         <price> 70 </price>
12     </book>
13 </books>

Book基类

 1 public class Book {
 2     private String no;
 3     private String title;
 4     private String author;
 5     private Double price;
 6 
 7     public String getNo() {
 8         return no;
 9     }
10 
11     public void setNo(String no) {
12         this.no = no;
13     }
14 
15     public String getTitle() {
16         return title;
17     }
18 
19     public void setTitle(String title) {
20         this.title = title;
21     }
22 
23     public String getAuthor() {
24         return author;
25     }
26 
27     public void setAuthor(String author) {
28         this.author = author;
29     }
30 
31     public Double getPrice() {
32         return price;
33     }
34 
35     public void setPrice(double d) {
36         this.price = d;
37     }
38 
39     @Override
40     public String toString() {
41         return "book [no=" + no + ", title=" + title + ", author=" + author + ", price=" + price + "]";
42     }
43 
44     public Book() {
45         super();
46         // TODO Auto-generated constructor stub
47     }
48 
49     public Book(String no, String title, String author, Double price) {
50         super();
51         this.no = no;
52         this.title = title;
53         this.author = author;
54         this.price = price;
55     }
56 
57 }

XMLParser接口

1 import java.util.List;
2 
3 public interface XMLParser {
4 public List<Book> parseXML(String filename);
5 
6 }

SaxHandler处理程序

 1 /*
 2  * 
 3  * 提供事件回调方法
 4  * */
 5 import java.util.ArrayList;
 6 import java.util.List;
 7 
 8 import org.xml.sax.Attributes;
 9 import org.xml.sax.SAXException;
10 import org.xml.sax.helpers.DefaultHandler;
11 
12 public class MySaxHandler extends DefaultHandler {
13     private String tag;
14     private Book book;
15     private List<Book> list;
16 
17     public List<Book> getList() {
18         return list;
19     }
20 
21     @Override
22     public void characters(char[] ch, int start, int length) throws SAXException {
23         super.characters(ch, start, length);
24         if (tag != null) {
25             String str = new String(ch, start, length).trim();
26             if (tag.equals("title")) {
27                 book.setTitle(str);
28             }
29             if (tag.equals("author")) {
30                 book.setAuthor(str);
31             }
32             if (tag.equals("price")) {
33                 book.setPrice(Double.parseDouble(str));
34             }
35 
36         }
37     }
38 
39     @Override
40     public void endDocument() throws SAXException {
41         super.endDocument();
42     }
43 
44     @Override
45     public void endElement(String uri, String localName, String qName) throws SAXException {
46         super.endElement(uri, localName, qName);
47         if (qName.equals("book")) {
48             list.add(book);
49             book = null;
50         }
51         tag = null;
52     }
53 
54     @Override
55     public void startDocument() throws SAXException {
56         super.startDocument();
57         list = new ArrayList<Book>();
58     }
59 
60     @Override
61     public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
62 
63         super.startElement(uri, localName, qName, attributes);
64         if (qName.equals("book")) {
65             book = new Book();
66             String no = attributes.getValue("bookno");
67             book.setNo(no);
68 
69         }
70         tag = qName;
71     }
72 
73 }

SaxParser 解析器

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.SAXException;

public class SaxParser implements XMLParser {

@Override
public List<Book> parseXML(String filename) {
List<Book> list = new ArrayList<Book>();
MySaxHandler handler = null;
//XML解析器
SAXParserFactory factory = SAXParserFactory.newInstance();
try {
// xml解析器
SAXParser parser = factory.newSAXParser();
//文件输入流
InputStream is = new FileInputStream(filename);
//处理程序
handler = new MySaxHandler();
//分配处理程序到解析器
parser.parse(is, handler);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//提取在处理程序中得到的容器
list = handler.getList();
return list;
}

public static void main(String[] args) {
XMLParser parser = new SaxParser();
List<Book> list = parser.parseXML("src\book.xml");
System.out.println("SAX解析结果：");
for (Book book : list) {
System.out.println(book.toString());
}

}