今天我们来聊聊SAX方式解析、生成XML文档
SAX介绍：
1、SAX方式解析XML
1、具体流程
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<accounts>
<account age="25" bankNo="acc1003">
<id>610105200210102233</id>
<name>小王</name>
<money>6000.0</money>
</account>
</accounts>
复制代码4、与xml的实体类Account.java
package com.yueqian.xml;
/**
* 封装xml的实体类
* @author LinChi
*
*/
public class Account {
private String bankNo;
private int age;
private String id;
private String name;
private double money;
public Account() {
super();
}
public Account(String bankNo, int age, String id, String name, double money) {
super();
this.bankNo = bankNo;
this.age = age;
this.id = id;
this.name = name;
this.money = money;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = 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 double getMoney() {
return money;
}
public void setMoney(double money) {
this.money = money;
}
public String getBankNo() {
return bankNo;
}
public void setBankNo(String bankNo) {
this.bankNo = bankNo;
}
@Override
public String toString() {
return this.bankNo+"|"+this.age+"|"+this.id+"|"+this.name+"|"+this.money;
}
}
复制代码5、定义事件监听器
package com.yueqian.xml2;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import com.yueqian.xml.Account;
/**
* 事件监听器
* @author LinChi
*
*/
public class AccountHandler extends DefaultHandler {
//存放结果
private List<Account> list = new ArrayList<Account>();
//存放正在解析的Account对象
private Account acc = null;
//存放正在解析的子标签名称
private String tagName = "";
//创建线程池处理多个线程入库
private ExecutorService exexutorPool = Executors.newFixedThreadPool(20);
/**
* 开始处理标签
*/
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
//当一个Account标签开始
if("account".equals(qName)) {
//创建对象
acc = new Account();
//获取属性
Map<String,Object> map = getAttrsInfo(attributes);
int age = 0;
try {
age = Integer.parseInt(map.get("age").toString());
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
acc.setAge(age);
String bankNo = null;
if(map.get("bankNo") != null) {
bankNo = map.get("bankNo").toString();
}
acc.setBankNo(bankNo);
}
//记录处理标签的名称
this.tagName = qName;
}
/**
* 结束标签
*/
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
//判断结束标签是否为account
if("account".equals(qName) && qName != null) {
//将对象添加到集合中
this.list.add(acc);
//判断list数据是否到达100万行数据，如果到达，处理入库，入库成功后，清空list
//转移数据时使用同步代码块保证多个线程执行数据的一致性
if(this.list.size() >= 1000000) {
List<Account> dbList = null;
synchronized (list) {
dbList = new ArrayList<Account>();
dbList.addAll(list);
list.clear();
}
//让dbList多线程去入库，处理高并发大数据入库使用多线程去执行
// new Thread(()->{
// //入库dbList
// }).start();
//使用线程池让多个线程入库
exexutorPool.execute(()->{
//入库dbList
});
}
}
//清空标签的名称
this.tagName = "";
}
/**
* 内容处理
*/
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if(this.acc == null) {
return;
}
//获取id属性标签
if("id".equals(this.tagName)) {
String id = String.valueOf(ch,start,length);
acc.setId(id);
}
//获取id属性标签
if("name".equals(this.tagName)) {
String name = String.valueOf(ch,start,length);
acc.setName(name);
}
//获取id属性标签
if("money".equals(this.tagName)) {
String moneyStr = String.valueOf(ch,start,length);
double money = 0;
try {
money = Double.parseDouble(moneyStr);
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
acc.setMoney(money);
}
}
/**
* 获取属性信息
* @param attributes
* @param sb
*/
private Map<String,Object> getAttrsInfo(Attributes attributes) {
Map<String,Object> attrMap = new HashMap<String,Object>();
//过滤非法
if(attributes == null || attributes.getLength() == 0) {
return attrMap;
}
//循环获取属性
for(int i = 0;i<attributes.getLength();i++) {
String key = attributes.getQName(i);
String var = attributes.getValue(i);
attrMap.put(key, var);
}
return attrMap;
}
public List<Account> getList() {
return list;
}
public void setList(List<Account> list) {
this.list = list;
}
}
复制代码6、创建解析器
package com.yueqian.xml2;
import java.io.File;
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 com.yueqian.xml.Account;
/**
* sax解析器
* @author LinChi
*
*/
public class TestSax {
public static void main(String[] args) {
//定义解析器工厂类对象，通过该工厂对象获取解析器
SAXParser parser;
try {
parser = SAXParserFactory.newInstance().newSAXParser();
//解析文件
// parser.parse(new File("I:/accs.xml"),new AccHandler());
//创建事件驱动对象
AccountHandler accHandler = new AccountHandler();
parser.parse(new File("I:/accs.xml"),accHandler);
List<Account> accList = accHandler.getList();
System.out.println(accList);
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
复制代码7、项目成果截图
2、SAX生成XML
1、实现思路
package com.yueqian.xml2;
import java.io.File;
import javax.swing.TransferHandler;
import javax.xml.crypto.dsig.Transform;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;
import org.xml.sax.Attributes;
import org.xml.sax.helpers.AttributesImpl;
/**
* Sax方式生成xml
* @author LinChi
*
*/
public class WriterSax {
public static void main(String[] args) throws Exception {
//创建保存xml的结果流对象
Result resultXml = new StreamResult(new File("I:/computer.xml"));
//获取Sax生成工厂实例
SAXTransformerFactory stf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
//获取SAX生成处理者对象实例
TransformerHandler transformerHandler = stf.newTransformerHandler();
//设置对象输入流
transformerHandler.setResult(resultXml);
//获取SAX生成器
Transformer transformer = transformerHandler.getTransformer();
//设置SAX生成文档 OutputKeys.INDENT表示文档可以有空格
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
//生成文档的开始
transformerHandler.startDocument();
//创建属性对象
AttributesImpl attrImpl = new AttributesImpl();
//添加属性
// attrImpl.addAttribute(uri, localName, qName, type, value);
//设置标签元素
transformerHandler.startElement("","","书籍列表",attrImpl);
transformerHandler.startElement("","","计算机书籍",attrImpl);
transformerHandler.startElement("","","书名",attrImpl);
//设置文本内容
transformerHandler.characters("java思想".toCharArray(), 0, "java思想".length());
//设置结尾标签
transformerHandler.endElement("", "", "书名");
transformerHandler.startElement("","","作者",attrImpl);
//设置文本内容
transformerHandler.characters("小王".toCharArray(), 0, "小王".length());
//设置结尾标签
transformerHandler.endElement("", "", "作者");
transformerHandler.startElement("","","价格",attrImpl);
//设置文本内容
transformerHandler.characters("79.00".toCharArray(), 0, "79.00".length());
//设置结尾标签
transformerHandler.endElement("", "", "价格");
//设置结尾标签
transformerHandler.endElement("","","计算机书籍");
//第二本书
transformerHandler.startElement("","","计算机书籍",attrImpl);
transformerHandler.startElement("","","书名",attrImpl);
//设置文本内容
transformerHandler.characters("Spring指南".toCharArray(), 0, "Spring指南".length());
//设置结尾标签
transformerHandler.endElement("", "", "书名");
transformerHandler.startElement("","","作者",attrImpl);
//设置文本内容
transformerHandler.characters("小李".toCharArray(), 0, "小李".length());
//设置结尾标签
transformerHandler.endElement("", "", "作者");
transformerHandler.startElement("","","价格",attrImpl);
//设置文本内容
transformerHandler.characters("89.00".toCharArray(), 0, "89.00".length());
//设置结尾标签
transformerHandler.endElement("", "", "价格");
//设置结尾标签
transformerHandler.endElement("","","计算机书籍");
transformerHandler.endElement("","","书籍列表");
//告诉Handle文档生成已经结束
transformerHandler.endDocument();
System.out.println("XML生成成功！");
}
}
复制代码3、成果截图