📅  最后修改于: 2020-11-10 05:18:19             🧑  作者: Mango
XStream支持注释,类似于自动配置而不是编码。在上一章中,我们已经在代码中看到了以下配置。
xstream.alias("student", Student.class);
xstream.alias("note", Note.class);
xstream.useAttributeFor(Student.class, "studentName");
xstream.aliasField("name", Student.class, "studentName");
xstream.addImplicitCollection(Student.class, "notes");
以下代码段说明了使用注释以更简单的方式完成相同工作的方法。
@XStreamAlias("student") //define class level alias
class Student {
@XStreamAlias("name") //define field level alias
@XStreamAsAttribute //define field as attribute
private String studentName;
@XStreamImplicit //define list as an implicit collection
private List notes = new ArrayList();
@XStreamOmitField //omit a field to not to be a part of XML
private int type;
}
让我们使用XStream测试上面的注释。
在C:\> XStream_WORKSPACE \ com \ tutorialspoint \ xstream中创建一个名为XStreamTester的Java类文件。
package com.tutorialspoint.xstream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.ArrayList;
import java.util.List;
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.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamAsAttribute;
import com.thoughtworks.xstream.annotations.XStreamImplicit;
import com.thoughtworks.xstream.annotations.XStreamOmitField;
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();
xstream.processAnnotations(Student.class);
//Object to XML Conversion
String xml = xstream.toXML(student);
System.out.println(formatXml(xml));
}
private Student getStudentDetails() {
Student student = new Student("Mahesh");
student.addNote(new Note("first","My first assignment."));
student.addNote(new Note("second","My Second assignment."));
student.setType(1);
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;
}
}
}
@XStreamAlias("student")
class Student {
@XStreamAlias("name")
@XStreamAsAttribute
private String studentName;
@XStreamImplicit
private List notes = new ArrayList();
public Student(String name) {
this.studentName = name;
}
public void addNote(Note note) {
notes.add(note);
}
public String getName() {
return studentName;
}
public List getNotes() {
return notes;
}
@XStreamOmitField
private int type;
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
}
@XStreamAlias("note")
class Note {
private String title;
private String description;
public Note(String title, String description) {
this.title = title;
this.description = description;
}
public String getTitle() {
return title;
}
public String getDescription() {
return description;
}
}
使用javac编译器编译类,如下所示:
C:\XStream_WORKSPACE\com\tutorialspoint\xstream>javac XStreamTester.java
现在运行XStreamTester以查看结果-
C:\XStream_WORKSPACE\com\tutorialspoint\xstream>java XStreamTester
验证输出如下-
first
My first assignment.
second
My Second assignment.
为了指示XStream框架处理注释,需要在序列化xml之前添加以下命令。
xstream.processAnnotations(Student.class);
要么
xstream.autodetectAnnotations(true);