xStream - 第一个应用程序

简述

在深入了解 XStream 库的细节之前，让我们先看看一个正在运行的应用程序。在这个例子中，我们创建了 Student 和 Address 类。我们将创建一个学生对象，然后将其序列化为 XML 字符串。然后反序列化相同的 XML 字符串以获取回学生对象。

在其中创建一个名为 XStreamTester 的 java 类文件 C:\>XStream_WORKSPACE.

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

使用编译类 javac 编译器如下 -


C:\XStream_WORKSPACE>javac XStreamTester.java

现在运行 XStreamTester 以查看结果 -


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

以下是此处要考虑的重要步骤。

步骤 1：创建 XStream 对象

通过将 StaxDriver 传递给 XStream 对象来创建它。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());
```
步骤 2：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);
```
步骤 3：反序列化 XML 以获取对象

使用 fromXML() 方法从 XML 中获取对象。
```
//XML to Object Conversion    
Student student1 = (Student)xstream.fromXML(xml);
```

xStream - 第一个应用程序

简述

要记住的步骤

步骤 1：创建 XStream 对象

步骤 2：将对象序列化为 XML

步骤 3：反序列化 XML 以获取对象