Question

我知道有很多关于在stackoverflow上从Java写到XML的问题，但它太复杂了。我觉得我有一个非常简单的问题，我无法弄明白。

所以我有一个程序需要大量用户输入，我现在正在创建并附加带有结果的文本文档。我将在这里发布我的作家代码：

 PrintWriter out = null;
         try {
             out = new PrintWriter(new BufferedWriter(new FileWriter("C:/Documents and Settings/blank/My Documents/test/test.txt", true)));
             out.println("");
             out.println("<event title=\""+titleFieldUI+"\"");
             out.println("  start=\""+monthLongUI+" "+dayLongUI+" "+yearLongUI+" 00:00:00 EST"+"\"");            
             out.println("  isDuration=\"true\"");
             out.println("  color=\""+sValue+"\"");
             out.println("  end=\""+monthLong1UI+" "+dayLong1UI+" "+yearLong1UI+" 00:00:00 EST"+"\"");
             out.println("  "+descriptionUI);
             out.println("");
             out.println("</event>");
             out.println("  <!-- Above event added by: " +System.getProperty("user.name")+" " +
                        "on: "+month+"/"+day+"/"+year+" -->");       
         }catch (IOException e) {
             System.err.println(e);
         }finally{
             if(out != null){
                 out.close();
             }
         }

所以最后，我希望它写入一个已经存在的XML文件（我可以通过简单地改变我的编写器所在的位置来完成）。问题是，这个XML文件有一个称为<data>的根标记。我需要将我的程序的结果放在XML文件的底部，但是要</data>之前。这是唯一的要求。我发现的一切看起来都太复杂了，我无法理解......

非常感谢任何帮助！

Answer 1

你应该使用一个不错的XML API。例如，以下是使用JDOM的示例：

import java.io.*;

import org.jdom2.*;
import org.jdom2.input.*;
import org.jdom2.output.*;

public class Test {
    public static void main(String args[]) throws IOException, JDOMException {
        File input = new File("input.xml"); 
        Document document = new SAXBuilder().build(input);
        Element element = new Element("event");
        element.setAttribute("title", "foo");
        // etc...
        document.getRootElement().addContent(element);

        // Java 7 try-with-resources statement; use a try/finally
        // block to close the output stream if you're not using Java 7
        try(OutputStream out = new FileOutputStream("output.xml")) {
            new XMLOutputter().output(document, out);
        }
    }
}

它真的并不那么难......而且它比手动写出来要强大得多。（例如，如果您的事件标题包含“＆amp;”，这将做正确的事情 - 而您的代码会产生无效的XML。）

Answer 2

如果您喜欢fluent api，则可以使用JOOX：

File file = new File("projects.xml");

Document document = $(file).document();

Comment eventComment = document.createComment("Above event added by: "
        + System.getProperty("user.name") + "\n" +
        " on: " + month + "/" + day + "/" + year);

document = $(file)
        .xpath("//data")
        .append($("event",
                $("title", "titleFieldUI"),
                $("start", monthLongUI + " " + dayLongUI + " " + yearLongUI + " 00:00:00 EST"),
                $("isDuration", "true"),
                $("color", sValue),
                $("end", monthLong1UI + " " + dayLong1UI + " " + yearLong1UI + " 00:00:00 EST")))
        .append($(eventComment))
        .document();

Transformer transformer = TransformerFactory.newInstance().newTransformer();
Result output = new StreamResult(file);
Source input = new DOMSource(document);

transformer.transform(input, output);

或XMLBuilder

XMLBuilder builder = XMLBuilder.parse(
        new InputSource(new FileReader("C:/Documents and Settings/blank/My Documents/test/test.txt")))
        .xpathFind("//data")
        .e("event")
        .a("title", titleFieldUI)
        .a("start", monthLongUI + " " + dayLongUI + " " + yearLongUI + " 00:00:00 EST")
        .a("isDuration", "true")
        .a("color", sValue)
        .a("end", monthLong1UI + " " + dayLong1UI + " " + yearLong1UI + " 00:00:00 EST")
        .up()
        .comment("Above event added by: " + System.getProperty("user.name") + "\n" +
                " on: " + month + "/" + day + "/" + year);

PrintWriter writer = new PrintWriter(new FileOutputStream("C:/Documents and Settings/blank/My Documents/test/test.txt"));
builder.toWriter(writer, new Properties());

Answer 3

您可以使用JOOX。这就是你如何做追加：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder parser = factory.newDocumentBuilder();
Document doc = parser.parse("/pathToXML");

JOOX.$(doc).append("<newNode>data<newNode>");

默认情况下，$（doc）将加载根节点。如果需要内部节点，可以使用find（）方法。该库没有很好的文档记录，但是开源，您可以随时直接检查源。

从Java写入XML文档 - 简单

3 个答案: