In -depth understanding of the principle of XSTREAM framework and the bottom layer

The XSTREAM framework is a popular Java object serialization library that can convert the Java object to XML format, or convert XML back to the Java object.This article will explore the principles and underlying implementation of XSTREAM. Introduction to XSTREAM framework XSTREAM is an open source Java framework developed by Joe Walnes. It provides a simple and powerful way to serialize and derived Java objects.The design goal of XSTREAM is to make XML serialization simple, fast and flexible, and the mapping relationship with the Java class should also be configured. Second, the principle of xstream The core principle of XSTREAM is to use annotated object-XML mapping technology.It recognizes the attributes of the Java class by using the annotation and reflection mechanism, and converts the Java object to XML format according to the configuration of the annotation, or converts XML back to the Java object. 1. Define XML alias Before using the Xstream framework, we must first define aliases for the Java class.This is achieved by using @xstreamalias annotations.In this way, XSTREAM knows how to convert the Java object into the label name of the XML node. Example code: @XStreamAlias("person") public class Person { private String name; private int age; // Getter and setter methods } 2. Object serialization For object serialization, we need to create a XSTREAM object and use the toxml method to convert the Java object into a XML format string. Example code: XStream xstream = new XStream(); Person Person = New Person ("Zhang San", 20); String xml = xstream.toXML(person); System.out.println(xml); Output results: <person> <name> Zhang San </name> <age>20</age> </person> 3. XML counter -serialization For XML's derivatives, we also need to create an Xstream object and use the FROMXML method to convert the XML string into a Java object. Example code: XStream xstream = new XStream(); String xml = "<person><name>张三</name><age>20</age></person>"; Person person = (Person) xstream.fromXML(xml); System.out.println (Person.getName ()); // Output: Zhang San System.out.println(person.getAge()); // Output: 20 Third, the underlying implementation of XSTREAM XSTREAM's underlying implementation mainly depends on Java's reflection mechanism and XML parser.It uses a reflection mechanism to dynamically obtain the attribute information of the Java object, and maps the attribute name to the label name of the XML node through the annotation configuration. XSTREAM supports a variety of XML parsers, such as DOM, SAX and STAX.By default, it uses the lightweight XML Pull parser of the XPP3 library to resolve XML.However, it can also be used to define the XML parser by calling XSTREAM's SetxmlReader and Setxmlwriter method. Fourth, summary The XSTREAM framework provides a simple and powerful way to serve the serialization and derivatives of the Java object.Its core principle is based on the annotation object-XML mapping technology. It recognizes the attributes of the Java class through the reflection mechanism, and converts the Java object to XML format according to the configuration of the annotation, or converts XML back to the Java object.At the same time, XSTREAM's underlying implementation depends on Java's reflection mechanism and XML parser. The above is a in -depth understanding of the principle of the XSTREAM framework and the bottom layer. By using XSTREAM, we can easily perform the conversion operation between Java objects and XML.