请问怎么设定让一个JTextArea只能输入200个字节，谢谢

Question

写事件，getText，转换成byte，判断是否超过200
应该可以实现吧没用过DocumentListener

Answer 1

用documentListener 监听JTextArea component 记录打击key的次数,来约束 
 
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
public class TextArea {
        static int length=0;
        JTextArea ta;
        TextArea()
          {
             JFrame frame=new JFrame();
             ta=new JTextArea();
             frame.getContentPane().add(ta);
             ta.setLineWrap(true);
             ta.getDocument().addDocumentListener(new DocumentListener() {
                                public void insertUpdate(DocumentEvent e) {
                                  if (length==200)
                                      ta.setEditable(false);
                                  length++;
                                }                                public void removeUpdate(DocumentEvent e) {
                                }                                public void changedUpdate(DocumentEvent e) {
                                }
                              });             frame.setSize(100,200);
             frame.setVisible(true);          }
  public static void main(String[] args) {
  new TextArea();  }
}