【XML】Java创建XML文档

package example01;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.nio.charset.StandardCharsets;

public class doit {
    public static void main(String[] args) {
        Document doc =  createDocument();
        Element root = doc.createElement("students");
        doc.appendChild(root);
        addStudentInfo(doc,root,"王宏","20100101","96","88","90");
        addStudentInfo(doc,root,"李娜","20100102","75","56","70");
        addStudentInfo(doc,root,"孙武","20100103","77","70","20");
        outputXMLFile(doc,"student.xml");
    }
    /* 通过DOM解析器创建一个空的Document对象 */
    public static Document createDocument() {
        // 通过newInstance方法创建DocumentBuilderFactory对象
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        Document doc = null;
        try {
            // 创建解析器对象
            DocumentBuilder db = dbf.newDocumentBuilder();
            // 创建一个空的Document对象
            doc = db.newDocument();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        }
        return doc;
    }
    public static void addStudentInfo(Document doc,Element root,String studentName,String studentId,String javaContent,String OracleContent,String umlContent){
        Element student = doc.createElement("student");
        student.setAttribute("id",studentId);
        root.appendChild(student);
        Element name = doc.createElement("name");
        name.setTextContent(studentName);
        student.appendChild(name);
        Element java = doc.createElement("java");
        java.setTextContent(javaContent);
        student.appendChild(java);
        Element oracle = doc.createElement("oracle");
        oracle.setTextContent(OracleContent);
        student.appendChild(oracle);
        Element uml = doc.createElement("uml");
        uml.setTextContent(umlContent);
        student.appendChild(uml);
    }
    /* 将内存中的DOM树输出为一个xml文档 */
    public static void outputXMLFile(Document doc,String filename) {
        try {
            TransformerFactory tff = TransformerFactory.newInstance();
            Transformer tf = tff.newTransformer();
            //设置输出XML文件的换行
            tf.setOutputProperty(OutputKeys.INDENT, "yes");
            //设置输出XML文件的缩进
            tf.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
            //把DOM对象转换为XML对象
            DOMSource source = new DOMSource(doc);
            //创建一个输出XML文件对象
            //StreamResult result = new StreamResult(new File(filename));
            StreamResult result = new StreamResult(new PrintStream(new FileOutputStream(filename),true, StandardCharsets.UTF_8));
            //把XML源代码输出为XML文件
            tf.transform(source, result);
        } catch (TransformerException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e);
        }

    }
}

关于编码问题

保存的XML是UTF-8格式

整个java项目也是UTF-8格式

我在写的过程中遇到了保存出来的XML文件有中文乱码的问题。

事情是这样的，老师发的Java文件是Eclipse写的，我用的Idea打开，然后打开中文乱码

于是我就把Java文件项目编码调成了GBK，结果写出来的文件就中文乱码了。

所以我在输出文件的函数那，把StreamResult result = new StreamResult(new File(filename));改成了StreamResult result = new StreamResult(new PrintStream(new FileOutputStream(filename),true, StandardCharsets.UTF_8));

你可以试一试这样，但是我这样并没有生效。

萌狼蓝天的解决方法是：

把项目编码，Java文件编码都设置成UTF-8，清除缓存重新启动即可。

萌狼-图1-修改项目编码

萌狼-图2-清除缓存