使用上述路径读取文件的Java GUI

JButton btnStart = new JButton("Start");
        btnStart.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {


                try{                
                    String filename =  fileName.getText();
                    FileReader fr = new FileReader(filename);
                    BufferedReader br = new BufferedReader(fr); 
                    Scanner scan = new Scanner(br);
                     filename = br.readLine();

                    if (filename != null){

                  String text = txtKeyword.getText();  
                  String line;
                  boolean hasError = true;

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

                if(line.contains(text)){
                    String newline = "\n";
                    jTextArea1.append(line + newline);
                    hasError = false;
                }   
                }
                if (hasError) {

                    JOptionPane.showMessageDialog(null, "Text Not Found");
                       br.close();
                       fr.close();
                    } 
                }}catch(IOException e){
                    JOptionPane.showMessageDialog(null, "File Not Found");
            }   }   
        });
JButton btnStart = new JButton("Start");