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Java 如何使用现有XML文档的属性创建新的XML文档？

java xml

Java 如何使用现有XML文档的属性创建新的XML文档？,java,xml,xml-parsing,Java,Xml,Xml Parsing,我有一个XML文档，如下所示： <?xml version="1.0" encoding="UTF-8"?> <model> <id>_1</id> <nodes> <id>_2</id> <stencil>TASK</stencil> </nodes> <nodes> <id>_3</id&

我有一个XML文档，如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<model>
    <id>_1</id>
    <nodes>
    <id>_2</id>
    <stencil>TASK</stencil>
    </nodes>
    <nodes>
    <id>_3</id>
    <stencil>TASK</stencil>
    </nodes>
</model>


_1
_2
任务
_3
任务
我必须使用第一个文档中的节点属性创建另一个xml文档。对于新文档，我必须创建一个父节点 称为“定义”。我必须在新文档中创建一个具有 属性“id”，其值与模型的“id”子节点的内容相同。对于第一个文档中的每个“节点”节点 如果他们的“模具”子节点内容等于“任务”，我将在新的xml文档中创建一个“任务”节点

<?xml version="1.0" encoding="UTF-8"?>
<definitions>
  <process id="_1">
    <task id="_2">
    </task>
    <task id="_3">
    </task>
  </process>
</definitions>
为此，我创建了三个类定义、过程和任务：

public class Definitions {
         public Process extractProcess(Document simpleXml_doc) throws XPathExpressionException{
            Process p = new Process();
            p.setProcess("process");
            XPath xPath = XPathFactory.newInstance().newXPath();
            XPathExpression xPathEx1 = xPath.compile("/model/id");
            Node n1 = (Node) xPathEx1.evaluate(simpleXml_doc, XPathConstants.NODE);
            p.setIdProcess(n1.getTextContent());
            return p;
        }
}

public class Process {

     private String process;
     public String getProcess(){
         return process;
     }
     public void setProcess(String process){
         this.process = process;
     }
         private String idProcess;
            public String getIdProcess(){
                return idProcess;
            }
            public void setIdProcess(String idProcess){
                this.idProcess = idProcess;
            }


    public ArrayList<Task> extractTasks(Document firstXml_doc) throws XPathExpressionException{
        ArrayList<Task> taskList = new ArrayList<>();
        XPath xPath = XPathFactory.newInstance().newXPath();
        XPathExpression xPathEx1 = xPath.compile("/model/nodes/stencil");
        NodeList nl1 = (NodeList) xPathEx1.evaluate(simpleXml_doc, XPathConstants.NODESET);
        for(int index=0; index<nl1.getLength(); index++){
            if(nl1.item(index).getTextContent().equals("TASK")){
                Task t = new Task();
                t.setTask("task");
                XPathExpression xPathEx2 = xPath.compile("/model/nodes/id");
                NodeList nl2 = (NodeList) xPathEx2.evaluate(simpleXml_doc, XPathConstants.NODESET);
                t.setIdTask("_" + nl2.item(index).getTextContent());
                taskList.add(t);
            }
        }
        return taskList;
    }
}

public class Task {
    private String task; 
    public String getTask(){
        return task;
    }
    public void setTask(String task){
        this.task = task;
    }
    //do krijoj properties per atributet e elementit task
    private String idTask;
    private String nameTask;
    public String getIdTask(){
        return idTask;
    }
    public void setIdTask(String idTask){
        this.idTask = idTask;
    }
}

公共类定义{
公共进程extractProcess（文档simpleXml_doc）抛出XPathExpressionException{
过程p=新过程（）；
p、 设定过程（“过程”）；
XPath=XPathFactory.newInstance（）.newXPath（）；
XPathExpression xPathEx1=xPath.compile（“/model/id”）；
Node n1=（Node）xpathx1.evaluate（simpleXml_doc，XPathConstants.Node）；
p、 setIdProcess（n1.getTextContent（））；
返回p；
}
}
公共类过程{
私有字符串处理；
公共字符串getProcess（）{
返回过程；
}
公共void setProcess（字符串进程）{
这个过程=过程；
}
私有字符串进程；
公共字符串getIdProcess（）{
返回idProcess；
}
公共void setIdProcess（字符串idProcess）{
this.idProcess=idProcess；
}
公共ArrayList extractTasks（Document firstXml_doc）抛出XPathExpressionException{
ArrayList taskList=新建ArrayList（）；
XPath=XPathFactory.newInstance（）.newXPath（）；
XPathExpression xPathEx1=xPath.compile（“/model/nodes/stencil”）；
NodeList nl1=（NodeList）xpathx1.evaluate（simpleXml_doc，XPathConstants.NODESET）；

对于（int index=0；index，我认为您在这里的想法是正确的，但是您可能想考虑使用JAXB来实现这一点。它更简洁、更容易理解。使用JAXB，您将把给定的输入XML文件解组为Java对象。然后，创建新的Java对象并将其封送回XML字符串/文件

以下是如何

让我们假设您具备以下条件：-

输入XML结构

这是您拥有的XML结构，并将其放入一个文件中

input.xml


<?xml version="1.0" encoding="UTF-8"?>
<model>
    <id>_1</id>
    <nodes>
        <id>_2</id>
        <stencil>TASK</stencil>
    </nodes>
    <nodes>
        <id>_3</id>
        <stencil>TASK</stencil>
    </nodes>
</model>


为输出XML创建JAVA对象

定义类


import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import java.util.List;

@XmlRootElement
public class Model {
    @XmlElement
    private String id;

    @XmlElement
    private List<Node> nodes;

    public Model() {
    }

    public Model(String id, List<Node> nodes) {
        this.id = id;
        this.nodes = nodes;
    }

    public String getId() {
        return id;
    }

    public List<Node> getNodes() {
        return nodes;
    }
}



import javax.xml.bind.annotation.XmlElement;

public class Node {

    @XmlElement
    private String id;

    @XmlElement
    private String stencil;

    public Node() {
    }

    public Node(String id, String stencil) {
        this.id = id;
        this.stencil = stencil;
    }

    public String getId() {
        return id;
    }

    public String getStencil() {
        return stencil;
    }
}



import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Definitions {

    @XmlElement
    private Process process;

    public Definitions() {
    }

    public Definitions(Process process) {
        this.process = process;
    }

    public Process getProcess() {
        return process;
    }
}



import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import java.util.List;

public class Process {

    @XmlAttribute
    private String id;

    @XmlElement
    private List<Task> task;

    public Process() {
    }

    public Process(String id, List<Task> task) {
        this.id = id;
        this.task = task;
    }

    public String getId() {
        return id;
    }

    public List<Task> getTask() {
        return task;
    }
}



import javax.xml.bind.annotation.XmlAttribute;

public class Task {

    @XmlAttribute
    private String id;

    public Task() {
    }

    public Task(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }
}



public class Main {
    public static void main(String[] args) throws JAXBException {

        // initialize JAXB
        JAXBContext context = JAXBContext.newInstance(Model.class, Definitions.class);

        // Unmarshal input XML into Java object
        Unmarshaller unmarshaller = context.createUnmarshaller();
        Model model = (Model) unmarshaller.unmarshal(Main.class.getClassLoader().getResourceAsStream("input.xml"));

        // Map old Java object to new Java object
        List<Task> tasks = new ArrayList<Task>();
        for (Node node : model.getNodes()) {
            tasks.add(new Task(node.getId()));
        }

        // Marshal new Java object into XML
        Definitions definitions = new Definitions(new Process(model.getId(), tasks));

        StringWriter sw = new StringWriter();

        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.setProperty(Marshaller.JAXB_ENCODING, "UTF-8");
        marshaller.marshal(definitions, sw);

        System.out.println(sw.toString());
    }
}


过程类


import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import java.util.List;

@XmlRootElement
public class Model {
    @XmlElement
    private String id;

    @XmlElement
    private List<Node> nodes;

    public Model() {
    }

    public Model(String id, List<Node> nodes) {
        this.id = id;
        this.nodes = nodes;
    }

    public String getId() {
        return id;
    }

    public List<Node> getNodes() {
        return nodes;
    }
}



import javax.xml.bind.annotation.XmlElement;

public class Node {

    @XmlElement
    private String id;

    @XmlElement
    private String stencil;

    public Node() {
    }

    public Node(String id, String stencil) {
        this.id = id;
        this.stencil = stencil;
    }

    public String getId() {
        return id;
    }

    public String getStencil() {
        return stencil;
    }
}



import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Definitions {

    @XmlElement
    private Process process;

    public Definitions() {
    }

    public Definitions(Process process) {
        this.process = process;
    }

    public Process getProcess() {
        return process;
    }
}



import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import java.util.List;

public class Process {

    @XmlAttribute
    private String id;

    @XmlElement
    private List<Task> task;

    public Process() {
    }

    public Process(String id, List<Task> task) {
        this.id = id;
        this.task = task;
    }

    public String getId() {
        return id;
    }

    public List<Task> getTask() {
        return task;
    }
}



import javax.xml.bind.annotation.XmlAttribute;

public class Task {

    @XmlAttribute
    private String id;

    public Task() {
    }

    public Task(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }
}



public class Main {
    public static void main(String[] args) throws JAXBException {

        // initialize JAXB
        JAXBContext context = JAXBContext.newInstance(Model.class, Definitions.class);

        // Unmarshal input XML into Java object
        Unmarshaller unmarshaller = context.createUnmarshaller();
        Model model = (Model) unmarshaller.unmarshal(Main.class.getClassLoader().getResourceAsStream("input.xml"));

        // Map old Java object to new Java object
        List<Task> tasks = new ArrayList<Task>();
        for (Node node : model.getNodes()) {
            tasks.add(new Task(node.getId()));
        }

        // Marshal new Java object into XML
        Definitions definitions = new Definitions(new Process(model.getId(), tasks));

        StringWriter sw = new StringWriter();

        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.setProperty(Marshaller.JAXB_ENCODING, "UTF-8");
        marshaller.marshal(definitions, sw);

        System.out.println(sw.toString());
    }
}


读取和写入XML

主类


import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import java.util.List;

@XmlRootElement
public class Model {
    @XmlElement
    private String id;

    @XmlElement
    private List<Node> nodes;

    public Model() {
    }

    public Model(String id, List<Node> nodes) {
        this.id = id;
        this.nodes = nodes;
    }

    public String getId() {
        return id;
    }

    public List<Node> getNodes() {
        return nodes;
    }
}



import javax.xml.bind.annotation.XmlElement;

public class Node {

    @XmlElement
    private String id;

    @XmlElement
    private String stencil;

    public Node() {
    }

    public Node(String id, String stencil) {
        this.id = id;
        this.stencil = stencil;
    }

    public String getId() {
        return id;
    }

    public String getStencil() {
        return stencil;
    }
}



import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Definitions {

    @XmlElement
    private Process process;

    public Definitions() {
    }

    public Definitions(Process process) {
        this.process = process;
    }

    public Process getProcess() {
        return process;
    }
}



import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import java.util.List;

public class Process {

    @XmlAttribute
    private String id;

    @XmlElement
    private List<Task> task;

    public Process() {
    }

    public Process(String id, List<Task> task) {
        this.id = id;
        this.task = task;
    }

    public String getId() {
        return id;
    }

    public List<Task> getTask() {
        return task;
    }
}



import javax.xml.bind.annotation.XmlAttribute;

public class Task {

    @XmlAttribute
    private String id;

    public Task() {
    }

    public Task(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }
}



public class Main {
    public static void main(String[] args) throws JAXBException {

        // initialize JAXB
        JAXBContext context = JAXBContext.newInstance(Model.class, Definitions.class);

        // Unmarshal input XML into Java object
        Unmarshaller unmarshaller = context.createUnmarshaller();
        Model model = (Model) unmarshaller.unmarshal(Main.class.getClassLoader().getResourceAsStream("input.xml"));

        // Map old Java object to new Java object
        List<Task> tasks = new ArrayList<Task>();
        for (Node node : model.getNodes()) {
            tasks.add(new Task(node.getId()));
        }

        // Marshal new Java object into XML
        Definitions definitions = new Definitions(new Process(model.getId(), tasks));

        StringWriter sw = new StringWriter();

        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.setProperty(Marshaller.JAXB_ENCODING, "UTF-8");
        marshaller.marshal(definitions, sw);

        System.out.println(sw.toString());
    }
}



公共类主{
公共静态void main（字符串[]args）抛出JAXBEException{
//初始化JAXB
JAXBContext context=JAXBContext.newInstance（Model.class，Definitions.class）；
//将XML输入到Java对象中
Unmarshaller Unmarshaller=context.createUnmarshaller（）；
Model Model=（Model）unmarshaller.unmarshal（Main.class.getClassLoader（）.getResourceAsStream（“input.xml”）；
//将旧Java对象映射到新Java对象
列表任务=新建ArrayList（）；
对于（节点：model.getNodes（））{
添加（新任务（node.getId（））；
}
//将新Java对象封送到XML中
定义=新定义（新流程（model.getId（），tasks））；
StringWriter sw=新的StringWriter（）；
Marshaller=context.createMarshaller（）；
setProperty（marshaller.JAXB_格式化的_输出，true）；
setProperty（marshaller.JAXB_编码，“UTF-8”）；
封送员。封送员（定义，sw）；
System.out.println（sw.toString（））；
}
}


结果

执行上述代码时，将获得以下XML字符串：-


<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<definitions>
    <process id="_1">
        <task id="_2"/>
        <task id="_3"/>
    </process>
</definitions>





根据您对问题的定义，我将把它作为纯粹的过程代码来处理：编写一些内容来遍历输入文档，提取所需的信息，并将结果值作为新的XML文档输出，而不是像开始那样构建完整的特定于应用程序的数据模型。或者只编写XSLT样式表这表达了你想要的转变。真的很有帮助，解释得很好。谢谢