概述
XStream为java.io.ObjectInputStream和ObjectOutputStream提供了替代的实现,允许以对象流方式进行XML序列化或者反序列化操作。
这对于处理集合对象非常有用(List<User> users),在内存中只保留一个User对象流。很显然,我们应该使用基于流而非DOM的XML解析器读取XML,以提高性能。
创建一个输出流,我们不得不提到HierarchicalStreamWriter. 它是一个接口,字面意思就是层级关系的输出流。 XStream默认提供了几个常用的实现类用于输出,比如CompactWriter和PrettyPrintWriter。
示例
package com.xgj.oxm.xstream.quickDemo.streamObject;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.PrintWriter;
import java.util.Date;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;
import com.xgj.oxm.xstream.quickDemo.domain.LoginLog;
import com.xgj.oxm.xstream.quickDemo.domain.User;
public class ObjectStreamDemo {
private static XStream xstream;
static {
xstream = new XStream();
}
/**
*
*
* @Title: objectToXml
*
* @Description: JAVA对象转化为XML
*
* @throws Exception
*
* @return: void
*/
public void objectToXml() throws Exception {
// (1)实例化序列化对象
User user = getUser();
// (2)创建一个PrintWriter对象,用于输出。
PrintWriter pw = new PrintWriter("D:\\ObjectStreamSample.xml");
// (3)创建一个HierarchicalStreamWriter的实现类来创建输出
PrettyPrintWriter ppw = new PrettyPrintWriter(pw);
// (4)创建对象输出流
ObjectOutputStream out = xstream.createObjectOutputStream(ppw);
out.writeObject(user);
out.close();
}
/**
*
*
* @Title: xmlToObject
*
* @Description: XML转化为JAVA对象
*
* @return
* @throws Exception
*
* @return: User
*/
public User xmlToObject() throws Exception {
// (1)我们需要通过对象流进行输入操作,需要FileReader和BufferedReader
FileReader fr = new FileReader("D:\\ObjectStreamSample.xml");
BufferedReader br = new BufferedReader(fr);
//(2)创建对象输入流
ObjectInputStream input = xstream.createObjectInputStream(br);
// (3)创建对象,通过ObjectInputStream中的readObject()方法将对象从XML文件中读取出来。
User user = (User) input.readObject();
return user;
}
/**
*
*
* @Title: getUser
*
* @Description: 初始化转换对象
*
* @return
*
* @return: User
*/
public static User getUser() {
LoginLog log1 = new LoginLog();
LoginLog log2 = new LoginLog();
log1.setIp("192.168.1.91");
log1.setLoginDate(new Date());
log2.setIp("192.168.1.92");
log2.setLoginDate(new Date());
User user = new User();
user.setId(1);
user.setUserName("xstream");
user.addLoginLog(log1);
user.addLoginLog(log2);
return user;
}
public static void main(String[] args) throws Exception {
ObjectStreamDemo converter = new ObjectStreamDemo();
converter.objectToXml();
User u = converter.xmlToObject();
for (LoginLog log : u.getLogs()) {
if (log != null) {
System.out.println("访问IP: " + log.getIp());
System.out.println("访问时间: " + log.getLoginDate());
}
}
}
}
示例源码
代码已托管到Github—> github.com/yangshangwe…