JBuilder 9 开发一个文本编辑器

Open menu item.
　　if (!okToAbandon()) {
　　return;
　　}
　　// Use the OPEN version of the dialog, test return for Approve/Cancel
　　if (JFileChooser.APPROVE_OPTION == jFileChooser1.showOpenDialog(this)) {
　　// Call openFile to attempt to load the text from file into
　　TextArea
　　openFile(jFileChooser1.getSelectedFile().getPath());
　　}
　　this.repaint();
　　}

　　 添加从文件中读出文字的代码

　　添加从选定的文件中将文字实际读到文本区JTextArea的代码。

　　首先需要在用户类中增加一个新的方法执行实际打开文件的操作，这个方法叫作openFile()。

　　// Open named file; read text from file into jTextArea1; report to statusBar.
　　void openFile(String fileName)
　　{
　　try
　　{
　　// Open a file of the given name.
　　File file = new File(fileName);
　　// Get the size of the opened file.
　　int size = (int)file.length();
　　// Set to zero a counter for counting the number of
　　// characters that have been read from the file.
　　int chars_read = 0;
　　// Create an input reader based on the file, so we can read its data.
　　// FileReader handles international character encoding conversions.
　　FileReader in = new FileReader(file);
　　// Create a character array of the size of the file,
　　// to use as a data buffer, into which we will read
　　// the text data.
　　char[] data = new char[size];
　　// Read all available characters into the buffer.
　　while(in.ready()) {
　　　// Increment the count for each character read,
　　　// and accumulate them in the data buffer.
　　　chars_read += in.read(data, chars_read, size - chars_read);
　　}
　　in.close();
　　// Create a temporary string containing the data,
　　// and set the string into the JTextArea.
　　jTextArea1.setText(new String(data, 0, chars_read));
　　// Display the name of the opened directory+file in the statusBar.
　　statusBar.setText("Opened "+fileName);
　　}
　　catch (IOException e)
　　{
　　statusBar.setText("Error opening "+fileName);
　　}
　　}

　　替换先前所说的File

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