sax连接数据库 Java Sax解析xml

Java Sax解析xml

https://blog.csdn.net/lp284558195/article/details/79136322

Article.java

DbHelper.java

MyHandler.java

SAXParserDemo.java

1.创建xml中元素对象

package com.sc;

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

public class Article {
	private List<String> authors;
	private String title;
	private String pages;
	private Integer year;
	private Integer volume;
	private String journal;
	private String number;
	private String ee;
	private String url;
	
	public Article() {
		authors = new ArrayList<>();
	}

	public Article(List<String> authors, String title, String pages, Integer year, Integer volume, String journal,
			String number, String ee, String url) {
		this.authors = authors;
		this.title = title;
		this.pages = pages;
		this.year = year;
		this.volume = volume;
		this.journal = journal;
		this.number = number;
		this.ee = ee;
		this.url = url;
	}

	public List<String> getAuthors() {
		return authors;
	}

	public void setAuthors(List<String> authors) {
		this.authors = authors;
	}
	
	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}

	public String getPages() {
		return pages;
	}

	public void setPages(String pages) {
		this.pages = pages;
	}

	public Integer getYear() {
		return year;
	}

	public void setYear(Integer year) {
		this.year = year;
	}

	public Integer getVolume() {
		return volume;
	}

	public void setVolume(Integer volume) {
		this.volume = volume;
	}

	public String getJournal() {
		return journal;
	}

	public void setJournal(String journal) {
		this.journal = journal;
	}

	public String getNumber() {
		return number;
	}

	public void setNumber(String number) {
		this.number = number;
	}

	public String getEe() {
		return ee;
	}

	public void setEe(String ee) {
		this.ee = ee;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}
}

2.开始编写SaxParserHandler，

sax处理xml文件常用到一下五个方法，也是sax解析xml文件的流程： 

startDocument —>文档读取开始 
startElement —>标签读取开始 
characters —>读取标签的内容 
endElement —>标签读取结束 

endDocument —>文档读取结束 

sax处理xml文档时，首先会读取该文档，调用startDocument 方法，标志着xml文件解析的开始，然后是逐标签读取，方式是读取开始标签调用startElement、读取标签内容调用characters、读取结束标签调用endElement。

package com.sc;

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

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class MyHandler extends DefaultHandler {
	private List<Article> articles = new ArrayList<>();
	private Article article = null;
	private int propertyOrder = 0;
	List<String> author = null;
	
	/*
	 * startDocument()：文档解析开始时调用，该方法只会调用一次 
	 * startElement(String uri, String localName, String qName, Attributes attributes):
	 * 标签（节点）解析开始时调用	 *
	 *  
	 * uri：xml文档的命名空间 
	 * localName：标签的名字
	 *  qName：带命名空间的标签的名字 
	 *  attributes：标签的属性集
	 *  
	 * 
	 * endElement(String uri, String localName, String qName)：标签（节点）解析结束后调用
	 * endDocument()：文档解析结束后调用，该方法只会调用一次
	 */
	
	@Override
	public void startDocument() throws SAXException {
		System.out.println("文档开始");
	}
	
	@Override
	public void endDocument() throws SAXException {
		System.out.println("文档结束");
	}
	
	@Override
	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
		if (qName.equals("article")) { 
			article = new Article();
			return;
		}
		switch (qName) {
		case "author":	
			propertyOrder = 1;
			break;
		case "title":	
			propertyOrder = 2;
			break;
		case "pages":	
			propertyOrder = 3;
			break;
		case "year":	
			propertyOrder = 4;
			break;
		case "volume":	
			propertyOrder = 5;
			break;
		case "journal":	
			propertyOrder = 6;
			break;
		case "number":	
			propertyOrder = 7;
			break;
		case "ee":	
			propertyOrder = 8;
			break;
		case "url":	
			propertyOrder = 9;
			break;
		}
	}
	
	@Override
	public void endElement(String uri, String localName, String qName) throws SAXException {
		if (qName.equals("article")) {
			articles.add(article);
			article = null;
		}
	}
	
	/*
	 * characters(char[] ch, int start, int length)：解析标签的内容的时候调用
	 * 
	 * ch：当前读取到的TextNode(文本节点)的字节数组 
	 * 
	 * start：字节开始的位置，为0则读取全部 
	 * 
	 * length：当前TextNode的长度*/
	@Override
	public void characters(char[] ch, int start, int length) throws SAXException {
		String content = new String(ch, start, length);
		switch (propertyOrder) {
		case 1:
			if (author == null) {
				author = new ArrayList<>();
			}
			author.add(content);
			break;
		case 2:
			if (author == null) {
				author = new ArrayList<>();
				author.add(0, "");
			}
			article.setAuthors(author);
			//System.out.println(author == null);
			article.setTitle(content);
			author = null;
			break;
		case 3:
			article.setPages(content);
			break;
		case 4:
			article.setYear(Integer.parseInt(content));
			break;
		case 5:
			article.setVolume(Integer.parseInt(content));
			break;
		case 6:
			article.setJournal(content);
			break;
		case 7:
			article.setNumber(content);
			break;
		case 8:
			article.setEe(content);
			break;
		case 9:
			article.setUrl(content);
			break;
		}
	}
	
	List<Article> getArticles() {
		return articles;
	}
}

3.saxparserdemo

package com.sc;

import java.io.IOException;
import java.util.List;

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

import org.xml.sax.SAXException;
//import org.xml.sax.helpers.DefaultHandler;

public class SAXParserDemo {

	public static void main(String[] args) {
		SAXParserFactory factory = SAXParserFactory.newInstance();
		try {
			SAXParser parser = factory.newSAXParser();
			MyHandler handler = new MyHandler(); // 使用自定义Handler
			parser.parse("dblp/dblp.xml", handler);
			System.out.println("Done.");
			
			List<Article> articles = handler.getArticles();
			DbHelper dbHelper = DbHelper.getDbHelper();
			int len = articles.size();
			for (int i = 0;i < len;++i) {
				Article article = articles.get(i);
				StringBuffer authorsName = new StringBuffer();
				
				for (int j = 0;j < article.getAuthors().size();++j) {
					if (j > 0) {
						authorsName.append(",");
					}
					authorsName.append(article.getAuthors().get(j));
				}
				
				String authorName = authorsName.toString();
				
				dbHelper.executeUpdate("insert into data(authors, title, pages, year, volume, journal, number, ee, url) values(?, ?, ?, ?, ?, ?, ?, ?, ?)", 
						authorName, article.getTitle(), article.getPages(), article.getYear(), article.getVolume(), article.getJournal(), article.getNumber(), article.getEe(), article.getUrl());
			}
			dbHelper.close();
			
		} catch (ParserConfigurationException | SAXException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

4.dbhelper.java

package com.sc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

/**
 * 数据库辅助工具类
 * @author Administrator
 *
 */
public class DbHelper {
	private static final String DRIVER = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
	private static final String URL = "jdbc:sqlserver://127.0.0.1:1433;Database=information";
	private static final String USER = "sc";
	private static final String PASSWORD = "sc";
	
	private static DbHelper dbHelper = null; 
	
	private Connection connection = null;
	
	static {
		try {
			Class.forName(DRIVER);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * 获取DbHelper实例
	 * @return
	 * @throws Exception
	 */
	public static DbHelper getDbHelper() throws Exception {
		if (dbHelper == null) {
			dbHelper = new DbHelper();
		}
		return dbHelper;
	}
	
	/**
	 * 私有构造方法
	 * @throws Exception
	 */
	private DbHelper() throws Exception {
		connection = DriverManager.getConnection(URL, USER, PASSWORD);
	}
	
	/**
	 * 执行查询
	 * @param sql
	 * @return
	 * @throws Exception
	 */
	public ResultSet executeQuery(String sql) throws Exception {
		Statement stmt = connection.createStatement();
		return stmt.executeQuery(sql);
	}
	
	/**
	 * 执行更新
	 * @param sql
	 * @return
	 * @throws Exception
	 */
	public int executeUpdate(String sql) throws Exception {
		Statement stmt = connection.createStatement();
		return stmt.executeUpdate(sql);
	}
	
	/**
	 * 执行条件查询
	 * @param sql
	 * @param objects 参数
	 * @return
	 * @throws Exception
	 */
	public ResultSet executeQuery(String sql, Object...objects) throws Exception {
		PreparedStatement stmt = connection.prepareStatement(sql);
		if (objects != null) {
			for (int i = 0; i < objects.length; i++) {
				Object param = objects[i];
				stmt.setObject(i+1, param);
			}
		}
		ResultSet result = stmt.executeQuery();
		return result;
	}
	
	/**
	 * 根据参数执行跟新操作
	 * @param sql SQL语句
	 * @param objects 参数值
	 * @return
	 * @throws Exception
	 */
	public int executeUpdate(String sql, Object...objects) throws Exception {
		PreparedStatement stmt = connection.prepareStatement(sql);
		if (objects != null) {
			for (int i = 0; i < objects.length; i++) {
				Object param = objects[i];
				stmt.setObject(i+1, param);
			}
		}
		int result = stmt.executeUpdate();
		return result;
	}
	
	/**
	 * 关闭操作
	 */
	public void close() {
		try {
			if (connection != null && !connection.isClosed()) {
				connection.close();
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			connection = null;
			dbHelper = null;
		}
	}
}

***dblp.xml***

<?xml version="1.0"  encoding="utf-8" ?>
<!DOCTYPE dblp SYSTEM "dblp.dtd">
<dblp><article mdate="2017-05-11" key="journals/ijtm/LuMW10">
<author>Iuan-Yuan Lu</author>
<author>Chih-Jen Mao</author>
<author>Chun-Hsien Wang</author>
<title>Intrafirm technology and knowledge transfer: a best practice perspective.</title>
<pages>338-356</pages>
<year>2010</year>
<volume>49</volume>
<journal>IJTM</journal>
<number>4</number>
<ee>https://doi.org/10.1504/IJTM.2010.030162</ee>
<url>db/journals/ijtm/ijtm49.html#LuMW10</url>
</article>
</dbcp>