java中实现xml schema 验证文件
XML 是可扩展标记语言，也就是说其中的标记我们可以按照我们的意愿生成，只要符合语法规则就认为是合法的。
但是很多情况下我们需要根据一定的验证规则对xml 文档实施限制。当我们书写一个xml 文档的时候，通过验证文档对其进行验证，可以保证所书写的文档是合法合理的。这样我们的程序才可以对其进行适当的操作。不然随意写一个符合语法的xml 文档，我们的程序显然不能总是能对其进行操作。
验证文档对所书写的xml 文档进行合理合法的验证，验证文档有两种格式，一种为dtd ，一种为xsd （schema 形式）。
Xsd 文档主要起一个验证作用!
我们可以在操作一个传输过来的，或者新生成的xml 文档先进行验证，然后再进行解析，这样可以保证操作成功。
在此，我们使用schema 格式的文档对xml 进行验证。
<? xml version = "1.0" encoding = "UTF-8" ?>
<!--W3C Schema generated by XMLSpy v2008 (http://www.altova.com)-->
< xs:schema xmlns = "http://www.frank.com"
xmlns:xs = "http://www.w3.org/2001/XMLSchema" targetNamespace = "http://www.frank.com" elementFormDefault = "qualified" >
< xs:element name = "students" >
< xs:complexType >
< xs:sequence >
< xs:element ref = "student" maxOccurs = "unbounded" />
</ xs:sequence >
</ xs:complexType >
</ xs:element >
< xs:element name = "student" >
< xs:complexType >
< xs:sequence >
< xs:element ref = "name" />
< xs:element ref = "age" />
</ xs:sequence >
</ xs:complexType >
</ xs:element >
< xs:element name = "name" type = "xs:string" />
< xs:element name = "age" type = "xs:byte" />
</ xs:schema >
<? xml version = "1.0" encoding = "UTF-8" ?>
< my:students xmlns:my = "http://www.frank.com" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" >
< my:student >
< my:name > tom </ my:name >
< my:age > 23 </ my:age >
</ my:student >
< my:student >
< my:name > mike </ my:name >
< my:age > 23 </ my:age >
</ my:student >
</ my:students >
package test;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import org.xml.sax.SAXException;
public class TestXML {
/**
* @param args
*/
public static void main(String[] args) throws SAXException, IOException {
// 建立 schema 工厂
SchemaFactory schemaFactory = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");
// 建立验证文档文件对象，利用此文件对象所封装的文件进行 schema 验证
File schemaFile = new File("C:/Documents and Settings/pengch/workspace/xmlschema/test/students.xsd");
// 利用 schema 工厂，接收验证文档文件对象生成 Schema 对象
Schema schema = schemaFactory.newSchema(schemaFile);
// 通过 Schema 产生针对于此 Schema 的验证器，利用 students.xsd 进行验证
Validator validator = schema.newValidator();
// 得到验证的数据源，就是 students.xml
Source source = new StreamSource("C:/Documents and Settings/pengch/workspace/xmlschema/test/students.xml");
// 开始验证，成功输出 success!!! ，失败输出 fail
try {
validator.validate(source);
System.out.println("success!!!");
} catch (Exception ex) {
System.out.println("fail");
}
}
}
抽象一下：
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
public class DefaultErrorHandler implements ErrorHandler {
protected static Log logger = LogFactory.getLog(DefaultErrorHandler.class);
public void error(SAXParseException exception) throws SAXException {
if(logger.isErrorEnabled()) {
logger.error("XML file is invalid", exception);
}
throw new SAXException(exception);
}
public void fatalError(SAXParseException exception) throws SAXException {
if(logger.isErrorEnabled()) {
logger.error("XML file is invalid", exception);
}
throw new SAXException(exception);
}
public void warning(SAXParseException exception) throws SAXException {
if(logger.isWarnEnabled()) {
logger.warn("Warning", exception);
}
exception.printStackTrace();
}
}
import java.io.IOException;
import java.io.InputStream;
import javax.xml.XMLConstants;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
public class DefaultSchemaValidator extends SchemaValidator {
private InputStream schemaStream;
/**
* 构造函数
* @param schemaStream schema 文件输入流
*/
public DefaultSchemaValidator(InputStream schemaStream) {
this.schemaStream = schemaStream;
}
/**
* 构造函数
* @param clz
* @param schemaFile schema 文件
*/
public DefaultSchemaValidator(Class clz, String schemaFile) {
this.schemaStream = clz.getResourceAsStream(schemaFile);
}
public DefaultSchemaValidator(ClassLoader classLoader, String schemaFile) {
this.schemaStream = classLoader.getResourceAsStream(schemaFile);
}
public void validate(InputStream xmlStream, ErrorHandler errorHandler) throws SAXException, IOException {
Schema schema = createSchema(schemaStream);
Validator validator = schema.newValidator();
validator.setErrorHandler(errorHandler);
validator.validate(new StreamSource(xmlStream));
}
/**
* 验证给定的 xml 是否合法
*
* @return
* @throws SAXException
*/
protected Schema createSchema(InputStream schemaStream) throws SAXException {
SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
return schemaFactory.newSchema(new StreamSource(schemaStream));
}
}
import java.io.IOException;
import java.io.InputStream;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
public abstract class SchemaValidator {
public abstract void validate(InputStream xmlStream, ErrorHandler errorHandler) throws SAXException, IOException;
public void validate(InputStream xmlStream) throws SAXException, IOException {
validate(xmlStream, new DefaultErrorHandler());
}
}
import java.io.IOException;
import org.xml.sax.SAXException;
import com.DefaultSchemaValidator;
import com.SchemaValidator;
public class TestXML2 {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
SchemaValidator schemaValidator= new DefaultSchemaValidator(TestXML2.class,"Students.xsd");
try {
schemaValidator.validate(TestXML2.class.getResourceAsStream("students.xml"));
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
fon