using system.out.print() in a texarea

问题

Am developing an application to query the table and print it out in the JTextarea but not responding instead flagging an error 'illegal start of expression' please am new with i need help and this is my code thanks

try{
  //get connection to the database
      Connection myconn=DriverManager.getConnection("jdbc:mysql://localhost:3306/cbt_for_java", "root","");
  //create a statement
      Statement mystmt=myconn.createStatement();
  //execute sql query
      ResultSet myrs = mystmt.executeQuery("select * from  jamb WHERE ID = '1'");
  //process the result set

     // System.out.println(myrs.getString("ID") + "." + myrs.getString("question"));


  }
  catch(Exception exc){
  exc.printStackTrace();
  }

  BorderLayout questionareaLayout = new BorderLayout();
  JPanel questionp = new JPanel();
  JTextArea question=new

//this is where the problem is
JTextArea(System.out.println(myrs.getString("ID") + "." + myrs.getString("question"));,22,111);
  question.setEditable(false);
  questionp.add(question);
  add(questionp);

回答1:

System.out.println() does have a return value, thus you cannot use it to set a value. What it does is write to the console.

To set a value in a textfield use the setText(), without the System.out.println

回答2:

Instead of the complex expression (that will not serve as a correct argument) passed as to the constructor of the JTextArea

System.out.println(myrs.getString("ID") + "." + myrs.getString("question"));,22,111

Try creating a String first, then passing that in as a parameter, like so:

String text = "id" + "text" + "stuff";
JTextArea question = new JTextArea(text);

回答3:

System.out.println will print out to the command line you cant use it to set the text in a JTextArea you need to do:

JTextArea question = new JTextArea(22,111);
question.setText(myrs.getString("ID") + "." + myrs.getString("question"));

回答4:

String s=myrs.getString("ID") + "." + myrs.getString("question");

here you will get your string in s now pass the string with along with other parameter.

JTextArea(s,22,111);

来源：https://stackoverflow.com/questions/31873037/using-system-out-print-in-a-texarea

标签

java

swing

jtextarea