第一个应用程序（First Application）

在进入XStream库的详细信息之前，让我们看一下应用程序的运行情况。 在这个例子中，我们创建了Student和Address类。 我们将创建一个student对象，然后将其序列化为XML String。 然后反序列化相同的XML字符串以获取学生对象。

在C:\》XStream_WORKSPACE创建名为XStreamTester的java类文件。

File: 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 int rollNo;
   private String firstName;
   private String lastName;
   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();
   }
}

Verify the Result

使用javac编译器编译类如下 -

C:\XStream_WORKSPACE>javac XStreamTester.java

现在运行XStreamTester来查看结果 -

C:\XStream_WORKSPACE>java XStreamTester

Verify the output as follows

<?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
   ] 
]

要记住的步骤

以下是需要考虑的重要步骤。

第1步:创建一个XStream对象

通过传递一个StaxDriver来创建一个XStream对象。 StaxDriver使用Stax pull解析器（可从java 6获得）并且是一个快速的xml解析器。

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

第2步:将对象序列化为XML

使用toXML（）方法获取对象的XML字符串表示形式。

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

第3步:反序列化XML以获取对象

使用fromXML（）方法从XML获取对象。

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