XStream入门应用程序

　　在进入XStream库的细节之前，让我们来看看应用程序操作。在这个例子中，我们创建Student和Address类。还将创建一个Student对象，然后将其序列化到一个XML字符串。然后反序列化的同一个XML字符串，以重新获得学生对象。

　　创建一个名为XStreamTester的Java类文件在 C:\>XStream_WORKSPACE.

文件: XStreamTester.java

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.stream.StreamResult;

import org.xml.sax.InputSource;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.StaxDriver;

public class XStreamTester {
   public static void main(String args[]){
      XStreamTester tester = new XStreamTester();
      XStream xstream = new XStream(new StaxDriver());

      Student student = tester.getStudentDetails();
      
	  //Object to XML Conversion
      String xml = xstream.toXML(student);
      System.out.println(formatXml(xml));

      //XML to Object Conversion		
      Student student1 = (Student)xstream.fromXML(xml);
      System.out.println(student1);
   }	

   private Student getStudentDetails(){
      Student student = new Student();
      student.setFirstName("Mahesh");
      student.setLastName("Parashar");
      student.setRollNo(1);
      student.setClassName("1st");

      Address address = new Address();
      address.setArea("H.No. 16/3, Preet Vihar.");
      address.setCity("Delhi");
      address.setState("Delhi");
      address.setCountry("India");
      address.setPincode(110012);

      student.setAddress(address);
      return student;
   }

   public static String formatXml(String xml){
      try{
         Transformer serializer= SAXTransformerFactory.newInstance().newTransformer();
         serializer.setOutputProperty(OutputKeys.INDENT, "yes");
         serializer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
         Source xmlSource=new SAXSource(new InputSource(new ByteArrayInputStream(xml.getBytes())));
         StreamResult res =  new StreamResult(new ByteArrayOutputStream());            
         serializer.transform(xmlSource, res);
         return new String(((ByteArrayOutputStream)res.getOutputStream()).toByteArray());
      }catch(Exception e){         
         return xml;
      }
   }
}

class Student {
   private String firstName;
   private String lastName;
   private int rollNo;
   private String className;
   private Address address;

   public String getFirstName() {
      return firstName;
   }
   public void setFirstName(String firstName) {
      this.firstName = firstName;
   }
   public String getLastName() {
      return lastName;
   }
   public void setLastName(String lastName) {
      this.lastName = lastName;
   }
   public int getRollNo() {
      return rollNo;
   }
   public void setRollNo(int rollNo) {
      this.rollNo = rollNo;
   }
   public String getClassName() {
      return className;
   }
   public void setClassName(String className) {
      this.className = className;
   }
   public Address getAddress() {
      return address;
   }
   public void setAddress(Address address) {
      this.address = address;
   }

   public String toString(){
      StringBuilder stringBuilder = new StringBuilder();
      stringBuilder.append("Student [ ");
      stringBuilder.append("\nfirstName: ");
      stringBuilder.append(firstName);
      stringBuilder.append("\nlastName: ");
      stringBuilder.append(lastName);
      stringBuilder.append("\nrollNo: ");
      stringBuilder.append(rollNo);
      stringBuilder.append("\nclassName: ");
      stringBuilder.append(className);
      stringBuilder.append("\naddress: ");
      stringBuilder.append(address);
      stringBuilder.append(" ]");
      return stringBuilder.toString();
   }
}

class Address {
   private String area;
   private String city;
   private String state;
   private String country;
   private int pincode;

   public String getArea() {
      return area;
   }
   public void setArea(String area) {
      this.area = area;
   }
   public String getCity() {
      return city;
   }
   public void setCity(String city) {
      this.city = city;
   }
   public String getState() {
      return state;
   }
   public void setState(String state) {
      this.state = state;
   }
   public String getCountry() {
      return country;
   }
   public void setCountry(String country) {
      this.country = country;
   }
   public int getPincode() {
      return pincode;
   }
   public void setPincode(int pincode) {
      this.pincode = pincode;
   }
   public String toString(){
      StringBuilder stringBuilder = new StringBuilder();
      stringBuilder.append("\nAddress [ ");
      stringBuilder.append("\narea: ");
      stringBuilder.append(area);
      stringBuilder.append("\ncity: ");
      stringBuilder.append(city);
      stringBuilder.append("\nstate: ");
      stringBuilder.append(state);
      stringBuilder.append("\ncountry: ");
      stringBuilder.append(country);
      stringBuilder.append("\npincode: ");	
      stringBuilder.append(pincode);
      stringBuilder.append(" ]");
      return stringBuilder.toString();
   }
}

验证结果

使用javac编译器编译如下类：

C:\XStream_WORKSPACE>javac XStreamTester.java

现在运行XStreamTester看到结果：

C:\XStream_WORKSPACE>java XStreamTester

验证输出

<?xml version="1.0" encoding="UTF-8"?>
<Student>
  <firstName>Mahesh</firstName>
  <lastName>Parashar</lastName>
  <rollNo>1</rollNo>
  <className>1st</className>
  <address>
    <area>H.No. 16/3, Preet Vihar.</area>
    <city>Delhi</city>
    <state>Delhi</state>
    <country>India</country>
    <pincode>110012</pincode>
  </address>
</Student>

Student [ 
firstName: Mahesh
lastName: Parashar
rollNo: 1
className: 1st
address: 
Address [ 
area: H.No. 16/3, Preet Vihar.
city: Delhi
state: Delhi
country: India
pincode: 110012 ] ]

记住以下步骤

以下是这里要考虑的重要步骤。

第1步：创建XStream对象。

通过它传递一个StaxDriver创建XStream对象。StaxDriver使用SAX解析器(可从Java6)，一个快速的XML解析器。

XStream xstream = new XStream(new StaxDriver());

第2步：序列化对象到XML。

使用toXML() 方法来获取对象的XML字符串表示。

//Object to XML Conversion
String xml = xstream.toXML(student);

第3步：反序列化XML获得对象。

使用 fromXML()方法来从XML对象。

//XML to Object Conversion		
Student student1 = (Student)xstream.fromXML(xml);