java gui 使用 split 函数在文本区域中显示

Question

嗨，我尝试在文本区域中使用分割功能，这样它只会向用户显示某些信息，目前我尝试使用一般编程中使用的典型方法进入 GUI 界面，但我相信我错误地实现了它。

    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) {

当前您打开BufferedReader，用它读取一些内容并直接关闭它。然后，您又想使用刚刚关闭的同一个阅读器再次阅读 br.readLine()。

br.close(); 应该在 finally block 中完成

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);
}