The technical principles and examples of the technical principles of Jackson DataFormat XML framework in the Java class library
Jackson DataFormat XML is a class library for processing XML in Java.It is an extension of the Jackson JSON processing framework that allows developers to read and write XML data.
The analysis of technical principles is as follows:
1. Data binding: Jackson DataFormat XML uses data binding to map XML data to the Java object.It uses Java annotations to specify the mapping relationship between XML elements and Java object attributes.Through the powerful characteristics of the JSON processing framework, we can bind XML data to the Java object without manual operation, and vice versa.
2. XML parser: Jackson DataFormat XML uses STAX as the default XML parser.STAX provides an event -based API that allows developers to analyze the XML data stream as needed.This analysis method avoids the problem of loading the entire XML document to the memory at one time, thereby improving performance and resource utilization.
3. Java object serialization and derivativeization: Jackson DataFormat XML uses Java reflection to achieve the serialization and derivatives of Java objects to XML.It can determine the name and structure of the generated XML element by reading the attributes and fields of the object.Similarly, it can match the attributes of the XML element with the attributes of the Java object and automatically bind the XML data to the Java object.
Below is an example code that uses Jackson DataFormat XML:
First of all, we need to add dependence on Jackson DataFormat XML:
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.13.0</version>
</dependency>
Suppose we have the following XML data:
<user>
<name>John</name>
<age>25</age>
</user>
Then, we can define a Java class to represent this XML data:
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
@JacksonXmlRootElement(localName = "user")
public class User {
@JacksonXmlProperty(localName = "name")
private String name;
@JacksonXmlProperty(localName = "age")
private int age;
// getters and setters
}
Next, we can use Jackson DataFormat XML to bind XML data to the Java object:
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
public class Main {
public static void main(String[] args) throws Exception {
String xml = "<user><name>John</name><age>25</age></user>";
ObjectMapper xmlMapper = new XmlMapper();
User user = xmlMapper.readValue(xml, User.class);
System.out.println (user.getName ()); // Output: John
System.out.println (user.getage ()); // Output: 25
}
}
The above code outputs "John" and "25", proving that we have successfully bound XML data to the Java object.
In short, Jackson DataFormat XML is a powerful Java class library that makes processing XML data in Java simple and efficient.It uses data binding principles and STAX parsers to achieve the serialization and derivativeization of XML, and also supports the mapping relationship between XML elements and Java objects of the annotation method.It is hoped that this article can help readers understand the technical principles of Jackson DataFormat XML and apply it in actual project development.
