网站开发营销网站多少钱,营销型网站建设策划书,wordpress和wamp,软文代写代发jaxb入门注意#xff1a;请查看我们的Java XML绑定JAXB教程– ULTIMATE指南 什么是JAXB#xff1f; JAXB代表用于XML绑定的Java体系结构。它用于将XML转换为java对象#xff0c;并将java对象转换为XML。JAXB定义了一个用于在XML文档中读写Java对象的API。与SAX和DOM不同请查看我们的Java XML绑定JAXB教程– ULTIMATE指南 什么是JAXB JAXB代表用于XML绑定的Java体系结构。它用于将XML转换为java对象并将java对象转换为XML。JAXB定义了一个用于在XML文档中读写Java对象的API。与SAX和DOM不同我们不需要了解XML解析技术。 您可以使用JAXB执行两种操作 编组 将Java对象转换为XML 编组 将XML转换为Java对象 JAXB教程 我们将创建一个封送和封送的Java程序。 对于编组 对于解组 Java程序 借助JAXB提供的注释和API将Java对象转换为XML反之亦然变得非常容易。 1.国家/地区 一个Java对象用于在XML之间进行转换 在src- org.arpit.javapostsforlearning.jaxb中创建Country.java package org.arpit.javapostsforlearning.jaxb;import java.util.ArrayList;import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;//Below annotation defines root element of XML file
XmlRootElement
//You can define order in which elements will be created in XML file
//Optional
XmlType(propOrder { countryName, countryPopulation, listOfStates})
public class Country {private String countryName;private double countryPopulation;private ArrayListstate listOfStates;public Country() {}public String getCountryName() {return countryName;}XmlElementpublic void setCountryName(String countryName) {this.countryName countryName;}public double getCountryPopulation() {return countryPopulation;}XmlElementpublic void setCountryPopulation(double countryPopulation) {this.countryPopulation countryPopulation;}public ArrayListstate getListOfStates() {return listOfStates;}// XmLElementWrapper generates a wrapper element around XML representationXmlElementWrapper(name stateList)// XmlElement sets the name of the entities in collectionXmlElement(name state)public void setListOfStates(ArrayListstate listOfStates) {this.listOfStates listOfStates;}} XmlRootElement此批注定义XML文件的根元素。 XmlTypepropOrder {属性列表顺序} 用于定义XML文件中元素的顺序。这是可选的。 XmlElement用于定义XML文件中的元素它设置实体名称。 XmlElementWrappername 要赋予该包装器的名称它围绕XML表示生成一个包装器元素。例如在上面的示例中它将生成stateList 每个state元素周围 2.状态库 package org.arpit.javapostsforlearning.jaxb;import javax.xml.bind.annotation.XmlRootElement;//Below statement means that class Country.java is the root-element of our example
XmlRootElement(namespace org.arpit.javapostsforlearning.jaxb.Country)
public class State {private String stateName;long statePopulation;public State(){}public State(String stateName, long statePopulation) {super();this.stateName stateName;this.statePopulation statePopulation;}public String getStateName() {return stateName;}public void setStateName(String stateName) {this.stateName stateName;}public long getStatePopulation() {return statePopulation;}public void setStatePopulation(long statePopulation) {this.statePopulation statePopulation;}
}3.JAXBJavaToXml.java package org.arpit.javapostsforlearning.jaxb;import java.io.File;
import java.util.ArrayList;import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;public class JAXBJavaToXml {public static void main(String[] args) {// creating country objectCountry countryIndianew Country(); countryIndia.setCountryName(India);countryIndia.setCountryPopulation(5000000);// Creating listOfStatesArrayListstate stateListnew ArrayListstate();State mpStatenew State(Madhya Pradesh,1000000);stateList.add(mpState);State maharastraStatenew State(Maharastra,2000000);stateList.add(maharastraState);countryIndia.setListOfStates(stateList);try {// create JAXB context and initializing MarshallerJAXBContext jaxbContext JAXBContext.newInstance(Country.class);Marshaller jaxbMarshaller jaxbContext.createMarshaller();// for getting nice formatted outputjaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);//specify the location and name of xml file to be createdFile XMLfile new File(C:\\arpit\\CountryRecord.xml);// Writing to XML filejaxbMarshaller.marshal(countryIndia, XMLfile); // Writing to consolejaxbMarshaller.marshal(countryIndia, System.out); } catch (JAXBException e) {// some exception occurede.printStackTrace();}}
} 运行以上程序后将得到以下输出 控制台输出 ?xml version1.0 encodingUTF-8 standaloneyes?
country xmlns:ns2org.arpit.javapostsforlearning.jaxb.CountrycountryNameIndia/countryNamecountryPopulation5000000.0/countryPopulationstateListstatestateNameMadhya Pradesh/stateNamestatePopulation1000000/statePopulation/statestatestateNameMaharastra/stateNamestatePopulation2000000/statePopulation/state/stateList
/country 现在我们将阅读上面生成的XML并从中获取国家对象。 4JAXBXMLToJava.java package org.arpit.javapostsforlearning.jaxb;import java.io.File;
import java.util.ArrayList;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;public class JAXBXMLToJava {public static void main(String[] args) {try {// create JAXB context and initializing MarshallerJAXBContext jaxbContext JAXBContext.newInstance(Country.class);Unmarshaller jaxbUnmarshaller jaxbContext.createUnmarshaller();// specify the location and name of xml file to be readFile XMLfile new File(C:\\arpit\\CountryRecord.xml);// this will create Java object - country from the XML fileCountry countryIndia (Country) jaxbUnmarshaller.unmarshal(XMLfile);System.out.println(Country Name: countryIndia.getCountryName());System.out.println(Country Population: countryIndia.getCountryPopulation());ArrayListstate listOfStatescountryIndia.getListOfStates();int i0; for(State state:listOfStates){i;System.out.println(State:i state.getStateName());}} catch (JAXBException e) {// some exception occurede.printStackTrace();}}
} 运行以上程序后将得到以下输出 控制台输出 Country Name: India
Country Population: 5000000.0
State:1 Madhya Pradesh
State:2 Maharastra JAXB的优点 它比DOM或SAX解析器简单易用 我们可以将XML文件编组到其他数据目标例如inputStreamURLDOM节点。 我们可以从其他数据目标中解组XML文件。 我们不需要了解XML解析技术。 我们不需要总是访问树结构中的XML。 JAXB的缺点 JAXB是高层API因此与SAX或DOM相比它对解析的控制更少。 它有一些开销的任务因此它比SAX慢。 源代码 下载 参考 JAXB教程–从我们的JCG合作伙伴 Arpit Mandliya 开始 有关初学者博客的Java框架和设计模式 。 翻译自: https://www.javacodegeeks.com/2013/02/jaxb-tutorial-getting-started.htmljaxb入门
