How to import CSV files into JTable for display using Java

Overview

Main knowledge points

a.SwingNode class: Encapsulates the Java swing component into a JavaFX Node, so that Java Swing can be nested with JavaFX. JavaSwing is ugly. , but the operation is simple. The table components of JavaFX (TableView, etc.) are a bit complicated, so choose nested JavaSwing to use it. Just be ugly

b.javacsv-2.0.jar: Used to read csv through file address file and can perform a series of operations. Although it will no longer be updated after 2008, it is enough to operate a csv file.

c.FileChoose class: A file selector for JavaFX that can open the local resource manager. Whether the UI is beautiful or not depends on your system version.

d.CsvReader class: A tool class under the javacsv-2.0.jar package, mainly used to operate csv files

e.JTable class: Create a JTable instance to make csv files After opening the display, you need to pay attention to the order of parameters. The table content is a two-dimensional array, and the header is a one-dimensional array

JTable table = new JTable(表格内容,表头);

f. Store the one-digit array into the one-dimensional array:

String[][] arr = new String[10][];//开辟一个10行的二维数组
String[] row1 = {"id","name","sex","age"};
 
arr[0] = row1;//存进二维数组

g. JTable does not display the header: you need to put the JTable object into a Pane

JTable table = new JTable(表内容,表头);
JScrollPane jScrollPane = new JScrollPane(table);
 
SwingNode swingNode = new SwingNode();
swingNode.setContent(jScrollPane);//使用swingNode封装swing组件，就可以在Javafx中用了

The main method of CsvReader

• new CsvReader(String filePath) initialization construction When you need to pass in a local csv file address

• boolean readHeaders() read the header and skip

• String[] getHeaders() Get the csv file header (very strange, you need to call the readHeaders() method before you can get it, otherwise a null pointer exception will be reported)

That's it:

CsvReader reader = new CsvReader("xxx.csv");
reader.readHeaders(); //没有这句话，执行下面会报错
String[] head = reader.getHeaders();

• boolean readRecord() reads a line of csv content. As long as you call it, the next time you call it, it will switch to the next line of csv. Usually we use a while loop to operate all the content line by line in time

• String getRawRecord() Read a row of data

while (reader.readRecord()){
    System.out.println(reader.getRawRecord());//输出一行内容
}

Example - Read a csv file on the local desktop

@Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("文件选择器");
        primaryStage.setHeight(600);
        primaryStage.setWidth(800);
 
        final FileChooser fileChooser = new FileChooser();
 
        //设置打开资源管理器后的文件过滤
        fileChooser.getExtensionFilters().addAll(
                new FileChooser.ExtensionFilter("All Images","*.*"),
                new FileChooser.ExtensionFilter("PNG","*.png"),
                new FileChooser.ExtensionFilter("MP4","*.mp4"),
                new FileChooser.ExtensionFilter("CSV","*.csv")
        );
 
        final Button open = new Button("打开文件");
 
        final GridPane inputGridPane = new GridPane();//创建格子布局面板
        GridPane.setConstraints(open,0,0);//第0行0列
 
        inputGridPane.setHgap(6.0);//设置水平间距
        inputGridPane.setVgap(6.0);//设置垂直间距
        inputGridPane.getChildren().addAll(open);//添加按钮
 
        final Pane rootGroup = new VBox(12);//创建一个垂直盒子布局器
        rootGroup.getChildren().addAll(inputGridPane);//把格子面板放进来
        rootGroup.setPadding(new Insets(12,12,12,12));
 
        primaryStage.setScene(new Scene(rootGroup));
        primaryStage.show();
 
//设置点击-打开文件-的动作事件
open.setOnAction(event -> {
            File file = fileChooser.showOpenDialog(primaryStage);//在当前窗口打开文件选择器
            if (file != null){
                try {
                    FileInputStream inputStream = new FileInputStream(file);
                    BufferedInputStream stream = new BufferedInputStream(inputStream);
                    String fileName = file.getName();
                    String filePath = file.getAbsolutePath();
                    System.out.println("文件路径 = "+filePath);
                    try {
                        CSVDemo.read(filePath);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }    
                    //封装JTable，使得JTable和Javafx嵌套在一起    
                    SwingNode swingNode = new SwingNode();
                    try {
                        JTable table = read(filePath);
                        JScrollPane jScrollPane = new JScrollPane(table);
                        swingNode.setContent(jScrollPane);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                //设置JTable打开后表格的相对位置
                GridPane.setConstraints(swingNode,0,1);
                    inputGridPane.getChildren().add(swingNode);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }
            }
        });
}
//读取csv文件并把它读取到JTable中返回
public static JTable read(String filePath) throws IOException {
 
            CsvReader reader = new CsvReader(filePath);
            reader.readHeaders();//跳过表头
            String[] head = reader.getHeaders();
 
            List<String []> list = new ArrayList<>();
            String s = reader.getRawRecord();
            System.out.println("表头 "+s);
            String[] r1 = dataToArray(s);
//            list.add(r1);
 
            while (reader.readRecord()) {
                System.out.println(reader.getRawRecord());
                list.add(dataToArray(reader.getRawRecord()));
            }
        String[][] data = new String[list.size()][];
        System.out.println("一共"+list.size()+"行数据");
        for (int i = 0; i < data.length; i++) {
            data[i] = list.get(i);
        }
            JTable table = new JTable(data,head);
            return table;
 
    }
//将每一行的数据从String转为String数组
    public static String[] dataToArray(String row){
        String[] res = row.split(",");
        return res;
    }

Effect Display

JScrollPane encapsulates JTable, SwingNode encapsulates JScrollPane

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