java gui使用split函数在文本区域中显示

Question

Hi im trying to use the split function within a textarea so it will only display certain information to the user, currently I tried to use the typical method used in general programming into the GUI interface however I believe I implemented it incorrectly.

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
    JFileChooser chooser = new JFileChooser();
        chooser.showOpenDialog(null);
        File f = chooser.getSelectedFile();
        String filename = f.getAbsolutePath();
    String st;
    String[] setdate = null;
    String[] submission = null;
    String[] title = null;
    String[] value = null;
    try 
    {
        FileReader reader = new FileReader (filename);
        BufferedReader br = new BufferedReader(reader);
        jTextArea1.read(br, null);
        br.close();
        jTextArea1.requestFocus();

    while ((st = br.readLine()) != null) {
        System.out.println(st); 
        if(st.contains("TITLE")) 
            title = st.split(":");
        if(st.contains("DATE SET"))
            setdate = st.split(":");                
        if(st.contains("SUBMISSION"))
            submission = st.split(":");
        if(st.contains("VALUE:"))
            value = st.split(":");
    }                  
    }
    catch (Exception e ) {
        JOptionPane.showMessageDialog( null, e);
    }
} 

cuurent display

Answer 1

FileReader reader = new FileReader (filename);
BufferedReader br = new BufferedReader(reader);
jTextArea1.read(br, null);
br.close();
jTextArea1.requestFocus();

while ((st = br.readLine()) != null) {

Currently you open the BufferedReader , read something with it and close it directly. Then again you want to read again using the same reader you just closed br.readLine() .

br.close(); should be done in a finally block

try (FileReader reader = new FileReader(filename); BufferedReader br = new BufferedReader(reader)) {
    jTextArea1.read(br, null);
    jTextArea1.requestFocus();

    while ((st = br.readLine()) != null) {
        System.out.println(st);
        if (st.contains("TITLE"))
            title = st.split(":");
        if (st.contains("DATE SET"))
            setdate = st.split(":");
        if (st.contains("SUBMISSION"))
            submission = st.split(":");
        if (st.contains("VALUE:"))
            value = st.split(":");
    }
} catch (Exception e) {
    JOptionPane.showMessageDialog(null, e);
}

Answer 2

jTextArea1.read(br, null);

The point of using the read(...) method of the JTextArea is to read data from a file and add the data to the text area.

So after invoking that method all the data in the file has already been read.

If you want to parse the data BEFORE adding the data to the text area, then you should NOT be using the read(...) method. Instead you just read each line of data from the file and then you use the append(...) method of the JTextArea to add the data.

if (st.contains("TITLE"))
    title = st.split(":");

Also, I don't know what the format of your file is but what do you expect that code to do. Every time you read a line containing TITLE you create a new array. I suspect instead you should create the array to get the data and then use the append(...) method to add the data to the text area.

But without a clear requirement we are only guessing.