[Java知识库]XML使用总结（一）

前言：日常开发过程中，经常会遇到需要将Java对象转XML或者将XML转Java对象，本篇是作者总结日常研发过程中Java与XML相互转换的方法，仅供参考。

一、Java封装的XML API

JAXB（Java Architecture for XML Binding简称JAXB）：允许Java开发人员将Java类映射为XML表示方式。JAXB提供两种主要特性：将一个Java对象序列化为XML，以及反向操作，将XML解析成Java对象。换句话说，JAXB允许以XML格式存储和读取数据，而不需要程序的类结构实现特定的读取XML和保存XML的代码。——摘自 OSChina《JAXB Java 的 XML 开发包》

1. 编写XML工具类

   import javax.xml.bind.JAXBContext;
   import javax.xml.bind.JAXBException;
   import javax.xml.bind.Marshaller;
   import javax.xml.bind.Unmarshaller;
   import java.io.StringReader;
   import java.io.StringWriter;
   
   public class XMLUtils {
   
       public static <T> String beanToXmlStr(T bean, String charset) throws JAXBException {
           JAXBContext jaxbContext = JAXBContext.newInstance(bean.getClass());
           Marshaller marshaller = jaxbContext.createMarshaller();
           marshaller.setProperty(Marshaller.JAXB_ENCODING, charset);
           StringWriter writer = new StringWriter();
           marshaller.marshal(bean, writer);
           return writer.toString();
       }
   
       public static <T> T xmlStrToBean(String xml, Class<T> clazz) throws JAXBException {
           JAXBContext jaxbContextResp = JAXBContext.newInstance(clazz);
           Unmarshaller unmarshaller = jaxbContextResp.createUnmarshaller();
           StringReader reader = new StringReader(xml);
           return (T) unmarshaller.unmarshal(reader);
       }
   
   }
   

2. 编写Java Bean

   import lombok.Data;
   
   import javax.xml.bind.annotation.XmlAccessType;
   import javax.xml.bind.annotation.XmlAccessorType;
   import javax.xml.bind.annotation.XmlElement;
   import javax.xml.bind.annotation.XmlRootElement;
   
   @Data
   @XmlRootElement(name = "Person")
   @XmlAccessorType(XmlAccessType.FIELD)
   public class Person {
       @XmlElement(name = "Name")
       private String name;
       @XmlElement(name = "Age")
       private Integer age;
   }
   

3. 测试

   import com.test.bean.Person;
   import org.junit.Test;
   
   import javax.xml.bind.JAXBException;
   
   public class TestXml {
       @Test
       public void test() throws JAXBException {
           // bean转xml字符串
           Person person = new Person();
           person.setName("Tom");
           person.setAge(20);
           String xmlStr = XMLUtils.beanToXmlStr(person, "UTF-8");
           System.out.println(xmlStr);
   
           // xml转bean
           Person person2 = XMLUtils.xmlStrToBean(xmlStr, Person.class);
           System.out.println(person2);
       }
   }
   

4. 运行结果截图
   

5. 详细资料请查阅：
   JAXB教程–入门
   JAXB Java 的 XML 开发包

二、XStream

XStream是一个Java对象和XML相互转换的工具，很好很强大。提供了所有的基础类型、数组、集合等类型直接转换的支持。因此XML常用于数据交换、对象序列化。——摘自 OSChina《XStream XML 操作类库》

1. 导入依赖

   <dependency>
     <groupId>com.thoughtworks.xstream</groupId>
     <artifactId>xstream</artifactId>
     <version>1.4.9</version>
   </dependency>
   <!-- lombok -->
   <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
     <version>1.18.2</version>
   </dependency>
   

2. 编写XStream工具类

   import com.thoughtworks.xstream.XStream;
   import com.thoughtworks.xstream.io.naming.NoNameCoder;
   import com.thoughtworks.xstream.io.xml.DomDriver;
   
   public class XStreamUtil {
   
       public static <T> T xmlStrToBean(String xml, Class<T> clazz) {
           XStream stream = new XStream(new DomDriver("UTF-8", new NoNameCoder()));
           stream.processAnnotations(clazz);
           stream.autodetectAnnotations(true);
           return (T) stream.fromXML(xml);
       }
   
       public static <T> String beanToXmlStr(T bean) {
           XStream stream = new XStream(new DomDriver("UTF-8", new NoNameCoder()));
           stream.autodetectAnnotations(true);
           return stream.toXML(bean);
       }
   
   }
   

3. 编写Java Bean

   import com.thoughtworks.xstream.annotations.XStreamAlias;
   import lombok.Getter;
   import lombok.Setter;
   import lombok.ToString;
   
   import java.util.Date;
   
   @Getter
   @Setter
   @ToString
   @XStreamAlias("Student")
   public class Student {
       @XStreamAlias("Name")
       private String name;
   
       @XStreamAlias("Sex")
       private String sex;
   
       @XStreamAlias("Age")
       private String age;
   
       @XStreamAlias("NickName")
       private String nickName;
   
       @XStreamAlias("IsSuccess")
       private Boolean isSuccess;
   
       @XStreamAlias("BirthDay")
       private Date birthDay;
   }
   

4. 编写测试方法

   
   public class TestXStream {
   	@Test
   	public void test() {
   		String xmlStr = "<Student>\n" +
               "    <Name>mingo</Name>\n" +
               "    <Sex>男</Sex>\n" +
               "    <NickName>luffy</NickName>\n" +
               "    <IsSuccess>true</IsSuccess>\n" +
               "    <BirthDay>1991-12-01 00:00:00</BirthDay>\n" +
               "</Student>";
           Student student = XStreamUtil.xmlStrToBean(xmlStr, Student.class);
           System.out.println(student);
   
   		String str = XStreamUtil.beanToXmlStr(student);
   		System.out.println(str);
   	}
   
   }
   

5. 运行结果截图
   
6. 详细资料请查阅：XStream XML 操作类库