java - 将 GUI 功能添加到编写 XML 文件的 Java 程序中

Question

我在这里有两个类。第一个是将数据写入 XML 文件，第二个是使用 JFrame，并使用按钮上的操作处理程序从三个文本字段收集数据。

我的两个问题:

1) GUI 是空白的 - 我已经有一段时间没有使用 JFrame 了，所以请耐心等待。

2) 我需要从文本框中提取 3 个字符串，并将它们插入到我的 insertNewEntry() 函数中。该属性只是一个我将递增的整数，元素和文档将分别是“rootElement”和“doc”。

非常感谢您的帮助!

import java.io.File;
import java.util.*;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
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 javax.swing.*;

import java.awt.*;

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

@SuppressWarnings("unused")
public class createXML extends JFrame {

    private static final long serialVersionUID = 1L;

    public static void main(String [] args) throws ParserConfigurationException, TransformerException{

        String address = "/home/leo/workspace/Test/Files/src/xmlOutput";
        Scanner s = new Scanner(System.in);
        int ID = 0;

        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.newDocument();

        Element rootElement = doc.createElement("Company");
        doc.appendChild(rootElement);

        GUI gui = new GUI();

        gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        gui.setSize(500, 300);
        gui.setVisible(true);


    //  insertNewEntry(rootElement, doc, ID, firstName, lastName, salary);


        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer t = tf.newTransformer();

        DOMSource source = new DOMSource(doc);
        StreamResult sr = new StreamResult(new File(address));

        t.transform(source, sr);

        System.out.println("File created.");

    }

    private static void insertNewEntry(Element rootElement, Document doc, String attr, String fName, String lName, String sal){


        Element employee = doc.createElement("Employee");
        employee.setAttribute("ID", attr);
        rootElement.appendChild(employee);

        Element firstName = doc.createElement("First_Name");
        firstName.setTextContent(fName);
        employee.appendChild(firstName);

        Element lastName = doc.createElement("Last_Name");
        lastName.setTextContent(lName);
        employee.appendChild(lastName);

        Element salary = doc.createElement("Salary");
        salary.setTextContent(sal);
        employee.appendChild(salary);

    }

}

下一个类...

import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

@SuppressWarnings("unused")
public class GUI extends JFrame {

    private static final long serialVersionUID = 1L;

    private JLabel item;
    private JTextField firstName;
    private JTextField lastName;
    private JTextField salary;
    private JButton button1;

    GUI(){

    super("XML Writer");

    JPanel panel = new JPanel();
    panel.setLayout(new GridLayout(0,2));

    JLabel fn = new JLabel("First Name");
    firstName = new JTextField();
    panel.add(fn);
    panel.add(firstName);

    JLabel ln = new JLabel("Last Name");
    lastName = new JTextField();
    panel.add(ln);
    panel.add(lastName);

    JLabel s = new JLabel("Salary");
    salary = new JTextField();
    panel.add(s);
    panel.add(salary);

    button1 = new JButton("Click Me!");
    button1.setSize(20, 10);
    panel.add(button1);

    Handler handler = new Handler();
    button1.addActionListener(handler);

    }

    private class Handler implements ActionListener{

        public void actionPerformed(ActionEvent event){

            String fn = ""; String ln = ""; String sal = "";

            fn = firstName.getText();
            ln = lastName.getText();
            sal = salary.getText();

            JOptionPane.showMessageDialog(null, "Information stored in XML file");

        }


    }

}

Answer 1

让我们从明显的问题开始......

您创建一个JPanel，添加您的组件，但永远不要将该面板添加到任何东西......

GUI() {

    super("XML Writer");

    JPanel panel = new JPanel();
    panel.setLayout(new GridLayout(0, 2));

    JLabel fn = new JLabel("First Name");
    firstName = new JTextField();
    panel.add(fn);
    panel.add(firstName);

    JLabel ln = new JLabel("Last Name");
    lastName = new JTextField();
    panel.add(ln);
    panel.add(lastName);

    JLabel s = new JLabel("Salary");
    salary = new JTextField();
    panel.add(s);
    panel.add(salary);

    button1 = new JButton("Click Me!");
    button1.setSize(20, 10);
    panel.add(button1);

    Handler handler = new Handler();
    button1.addActionListener(handler);

    //...???
}

尝试将面板添加到GUI...

    add(panel);
}

此外，您的 CreateXML 类不需要从 JFrame 扩展，它甚至没有使用它的任何功能...

你的第二个问题是一个意见问题......

基本的解决方案是调用 static createXML.insertNewEntry(...) 方法，但您的 GUI 缺少一些信息为了使这项工作成功，它需要......

就个人而言，我会创建一个“模型”接口(interface)，其中包含文档和一个简化的插入方法，该方法仅从图形用户界面...

更新了模型示例

基本模型结构...

public interface EmployeeModel {

    public void insert(String fName, String lName, String sal);

}

public interface XMLEmployeeModel extends EmployeeModel {

    public void save(File file) throws IOException;

}

public abstract class AbstractXMLEmployeeModel implements XMLEmployeeModel {

    private Document doc;

    public AbstractXMLEmployeeModel(Document doc) {
        this.doc = doc;
    }

    public Document getDoc() {
        return doc;
    }

    @Override
    public void save(File file) throws IOException {
        try {
            TransformerFactory tf = TransformerFactory.newInstance();
            Transformer t = tf.newTransformer();

            DOMSource source = new DOMSource(doc);
            StreamResult sr = new StreamResult(file);

            t.transform(source, sr);
        } catch (TransformerFactoryConfigurationError | TransformerException exp) {
            exp.printStackTrace();
            throw new IOException("Failed to save Employee model", exp);
        }
    }

}

public class DefaultXMLEmployeeModel extends AbstractXMLEmployeeModel {

    private int count = 0;

    public DefaultXMLEmployeeModel(Document doc) {
        super(doc);
    }

    @Override
    public void insert(String fName, String lName, String sal) {
        Document doc = getDoc();
        Element root = doc.getDocumentElement();

        Element employee = doc.createElement("Employee");
        employee.setAttribute("ID", Integer.toString(count++));
        root.appendChild(employee);

        Element firstName = doc.createElement("First_Name");
        firstName.setTextContent(fName);
        employee.appendChild(firstName);

        Element lastName = doc.createElement("Last_Name");
        lastName.setTextContent(lName);
        employee.appendChild(lastName);

        Element salary = doc.createElement("Salary");
        salary.setTextContent(sal);
        employee.appendChild(salary);
    }

}

以及使用它的 GUI 示例...

public static class GUI extends JFrame {
    //...
    private XMLEmployeeModel model;

    GUI(XMLEmployeeModel model) {

        super("XML Writer");

        this.model = model;
        //...
    }

    private class Handler implements ActionListener {

        public void actionPerformed(ActionEvent event) {

            String fn = "";
            String ln = "";
            String sal = "";

            fn = firstName.getText();
            ln = lastName.getText();
            sal = salary.getText();

            model.insert(fn, ln, sal, sal);

            JOptionPane.showMessageDialog(null, "Information stored in XML file");

        }

    }

}