SWT从文件中读取并在FormData

Question

你好我是一名初级java开发人员并且正在尝试学习SWT并制作一个程序但是我无法通过一个程序。程序打开一个文件，读取它并应该在FromData中显示内容但是我得到了一个例外，如果我尝试在控制台中打印它，它工作正常。 任何人都可以帮助我吗？

代码：

public abstract class CommonUtils {

protected Text text1, text2;
protected Font font;
protected StringBuffer sb;
protected Boolean opened;
protected Display display;

public String mptsvnFileDialog(Shell shell, String type) {
    FileDialog dialog;
    if (type == "OPEN") {
        dialog = new FileDialog(shell, SWT.OPEN);
    } else {
        dialog = new FileDialog(shell, SWT.SAVE);
    }

    String[] filterNames = new String[] { "MPT_PRODUCT File",
            "All Files (*)" };
    String[] filterExtensions = new String[] { "*.mpt_product", "*" };

    dialog.setFilterNames(filterNames);
    dialog.setFilterExtensions(filterExtensions);

    String patch = dialog.open();

    if (patch != null) {
        return patch;
    } else {
        return "";
    }

}

public void mptOpenFile(Shell shell, String fileOpen) {

    FileReader openFile = null;
    try {
        openFile = new FileReader(fileOpen);
    } catch (FileNotFoundException e) {
        MessageBox messageBox = new MessageBox(shell, SWT.ICON_ERROR
                | SWT.OK);
        messageBox.setMessage("Could not open file!");
        messageBox.setText("Error");
        messageBox.open();
        return;
    }
    BufferedReader fileInput = new BufferedReader(openFile);
    String text = null;
    sb = new StringBuffer();
    int count = 0;
    try {
        do {
            if (text != null)
                sb.append(new String(text.getBytes(), "UTF-8"));
            if (count != 0)
                sb.append('\n');
            count++;
        } while ((text = fileInput.readLine()) != null);
        fileInput.close();
    } catch (IOException e1) {
        MessageBox messageBox = new MessageBox(shell, SWT.ICON_ERROR
                | SWT.OK);
        messageBox.setMessage("Could not write to file!");
        messageBox.setText("Error");
        messageBox.open();
        return;
    }
       text1.setText(sb.toString());
    // opened = true;
    // System.out.println(sb);

}



public class MptSvnText extends CommonUtils {

public MptSvnText() {

}

public void mptSvnText(Display display, Shell shell) {
    text1 = new Text(shell, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL
            | SWT.BORDER);
    FormData data1 = new FormData();
    data1.top = new FormAttachment(0, 25);
    data1.left = new FormAttachment(0, 5);
    data1.right = new FormAttachment(50, -5);
    data1.bottom = new FormAttachment(100, -50);
    text1.setLayoutData(data1);

    text2 = new Text(shell, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL
            | SWT.BORDER);
    FormData data2 = new FormData();
    data2.top = new FormAttachment(0, 25);
    data2.left = new FormAttachment(50, 5);
    data2.right = new FormAttachment(100, -5);
    data2.bottom = new FormAttachment(100, -50);
    text2.setLayoutData(data2);

    text1.addListener(SWT.Activate, event -> {
        Point temp = text2.getSelection();
        text2.setSelection(temp.x);
    });

    text2.addListener(SWT.Activate, event -> {
        Point temp = text1.getSelection();
        text1.setSelection(temp.x);
    });

}

public class MptSvnShell {

public MptSvnShell() {

    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new FormLayout());

    shell.setText("MPT_SVN_Compatibility_Converter");
    shell.setSize(820, 600);

    MptSvnText text = new MptSvnText();
    text.mptSvnText(display, shell);
    MptSvnButtons buttons = new MptSvnButtons(shell);
    MptSvnToolbar toolbar = new MptSvnToolbar(shell);
    MptSvnMenu menu = new MptSvnMenu(display, shell);

    shell.open();

    while (!shell.isDisposed()) {
        if (!display.readAndDispatch()) {
            display.sleep();
        }
    }
}

}

我得到的例外：

Exception in thread "main" java.lang.NullPointerException
at com.mptsvn.abstractclasses.CommonUtils.mptOpenFile(CommonUtils.java:92)
at com.mptsvn.menu.MptSvnMenu.lambda$0(MptSvnMenu.java:50)
at com.mptsvn.menu.MptSvnMenu$$Lambda$8/1232367853.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4172)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
at com.mptsvn.menu.MptSvnMenu.<init>(MptSvnMenu.java:121)
at com.mptsvn.shell.MptSvnShell.<init>(MptSvnShell.java:27)
at com.mptsvn.test.Test.main(Test.java:9)