java - 处理文件的小程序在本地工作但在网站上失败

Question

几天来我一直在为这个问题苦苦思索。我已经完成了谷歌搜索的全部工作，我希望我能在这里找到比我更有经验的人(不难找到哈哈)来破译我的问题。

场景:我开发了一个实现 Swing GUI 的 Java Applet。后台工作:Applet 从一个大的“电话簿”excel 文件 (.csv) 中收集记录，并将它们存储在 map 数据结构中。电话簿包含大约 106,000 条记录，在第 34,586 条记录上，我得到一个我无法理解的 ArrayIndexOutOfBoundsException。 只有在我的个人网站上运行小程序时才会出现异常。在我的 IDE (NetBeans) 中测试并在我的本地计算机上运行 .html 文件(包含小程序的文件)时，小程序运行完美无误。在我的网站上运行时抛出的输出和异常如下(为了节省篇幅我把大部分记录都删掉了):

Java 控制台

Kary,Webber,2826 East 12th Ave.,Memphis,TN,38168,901-749-1834
Erinn,Rocha,2132 East Main Ave.,Memphis,TN,38168,865-414-5105
Gina,Lane,71 South First St. Apt. 11,Memphis,TN,38168,731-485-1129
Patsy,Hart,661 East 11th St.
java.lang.ArrayIndexOutOfBoundsException: 3
at Implementation.PersonnelDatabase.addRecordFromFields(PersonnelDatabase.java:192)
at Implementation.PersonnelDatabase.initDBFromFile(PersonnelDatabase.java:215)
at Implementation.PersonnelDatabase.processData(PersonnelDatabase.java:239)
at Implementation.PersonnelDatabaseApplet$2.doInBackground(PersonnelDatabaseApplet.java:78)
at Implementation.PersonnelDatabaseApplet$2.doInBackground(PersonnelDatabaseApplet.java:69)
at javax.swing.SwingWorker$1.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at javax.swing.SwingWorker.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

如您所见，在第 34,586 条记录(从 Patsy,Hart 开始)中，它输出了她地址的中途。完整记录如下:Patsy,Hart,661 East 11th St. Apt. 195,Memphis,TN,38168,555-555-5555。

以下是逻辑上受异常影响最大的代码部分。

HTML 文件中的对象标签

<object type="application/x-java-applet" height="400" width="300">
  <param name="codebase" value="classes" />
  <param name="code" value="Implementation/PersonnelDatabaseApplet.class" />
  <param name="archive" value="PersonnelDatabase.jar" />
  Applet failed to run. No Java plug-in was found.
</object>

PersonnelDatabase类(处理后台数据):

/*
 * Create a new record using an appropriately ordered set of fields and add it to the data base
 */
public void addRecordFromFields(String[] fields)
{
    // Read record attributes in, one at a time
    Record thisRecord = new Record();
    thisRecord.setFirstName(fields[0]);
    thisRecord.setLastName(fields[1]);
    thisRecord.setAddress(fields[2]);
    thisRecord.setCity(fields[3]);
    thisRecord.setState(fields[4]);
    thisRecord.setZipCode(fields[5]);
    thisRecord.setPhoneNo(fields[6]);
    addRecord(thisRecord);
}

// O( n )
/**
 * Destroy the current data base and load new data from a file.
 * @param filename the file to use as a source
 * @throws IOException: Either file not found or IO error
 */
public void initDBFromFile(URL url) throws IOException
{
    // Open and read the file
    InputStream in = url.openStream();
    BufferedReader filein = new BufferedReader(new InputStreamReader(in));
    // Read record file, parse lines, and add records to data base
    String line = filein.readLine();
    while(line != null) {
        System.err.println(line);
        String[] fields = line.split(",");
        addRecordFromFields(fields);
        line = filein.readLine();
    }
    filein.close();
}

/**
 * Loads the default library and provides for interaction with the data
 * via the JPanel GUI inputs.
 * @param args
 * @throws IOException 
 */
public String processData(String input, int selection, URL url)
{
    //Create the main library object
    PersonnelDatabase dbiLib = new PersonnelDatabase();
    System.err.println(url);
    // Try to read the default library
    try
    {
        dbiLib.initDBFromFile(url);
    }
    catch (IOException e)
    {
        System.err.println("File IO Error");
        e.printStackTrace();
        System.exit(1);
    }
    // Queries can be simulated by typing into the console in Eclipse, and using Ctrl-d (Ctrl-z in Windows) when finished.
    // For example: "searchLastName,Smith" would print a list of all people with the last name of Smith.
    Iterable<Record> result = null;
    String[] fields = new String[2];
    if (input.contains(",")) {
        fields = input.split(",");
    }

    switch(selection) {
        case 0: result = dbiLib.searchByFirstName(input); break;
        case 1: result = dbiLib.searchByLastName(input); break;
        case 2: result = dbiLib.searchByFullName(fields[0].trim(), fields[1].trim()); break;
        case 3: result = dbiLib.searchByCity(input); break;
        case 4: result = dbiLib.searchByState(input); break;
        case 5: result = dbiLib.searchByCityState(fields[0].trim(), fields[1].trim()); break;
        case 6: result = dbiLib.searchByZip(input); break;
        case 7: result = dbiLib.searchByPhoneNumber(input); break;
        case 8: String[] newFields = new String[fields.length-1];
                System.arraycopy(fields, 1, newFields, 0, fields.length-1);
                dbiLib.addRecordFromFields(newFields);
                return "Record added successfully!\nEnter a query or add another record.";
        default: return "Invalid query.\nEnter another query or add a record.";
    }

PersonnelDatabaseApplet 类(初始化 GUI、收集输入并显示输出):

public void init() {
    /* Create and display the applet */
    try {
        java.awt.EventQueue.invokeAndWait(new Runnable() {

            @Override
            public void run() {
                initComponents();
            }
        });
    } catch (Exception e) {
        System.err.println("Creation of GUI did not successfully complete.");
    }
}

// Process inputs in the background.
SwingWorker worker = new SwingWorker<String, Void>() {
    @Override
    public String doInBackground() {
        URL url = null;
        try {
            url = new URL(getCodeBase(), fileToRead);
        }
        catch(MalformedURLException e){}
        personnelDatabase = new PersonnelDatabase();
        final String output = personnelDatabase.processData(input, selection, url);
        return output;
    }

    @Override
    public void done() {
        processingLabel.setVisible(true);
        try {
            textToDisplay = get(15, TimeUnit.SECONDS);
        } catch (InterruptedException ignore) {
            ignore.printStackTrace();
        } catch (TimeoutException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            String why = null;
            Throwable cause = e.getCause();
            if(cause != null) {
                why = cause.getMessage();
                cause.printStackTrace();
            } else {
                why = e.getMessage();
                e.printStackTrace();
            }
            System.err.println("Error retrieving request: " + why);
            }
        if(worker.isDone() && textToDisplay != null) {
            processingLabel.setVisible(false);
            outputTextArea.setText(textToDisplay);
        }
    }
};

private void searchButtonActionPerformed(java.awt.event.ActionEvent evt) {                                             
selection = searchComboBox.getSelectedIndex();
input = valueTextField.getText();
processingLabel.setVisible(true);

worker.execute();

}

链接到我个人网站上的小程序: http://www.ryan-taylor.me/Applied%20Maps/build/PersonnelDatabaseApplet.html

我相当确定该错误与 excel 数据本身无关，因为该程序在 NetBeans 中以及在我的本地计算机上运行 html 时运行良好。我猜它与 Swing(线程)有关，但我不确定。我通过使用 SwingWorker 进行了更改以帮助在 Swing 线程之间传输数据，但我没有运气。我想我在实现它时总是有可能错过一些东西。

我也考虑过对 jar 进行签名，但是我正在处理的文件是在线存储的——而不是本地机器——所以我没有看到真正的需要。

如果有人有任何建议，我将不胜感激!

Answer 1

看起来越界的数组索引是3 ，因为输入行仅包含三个字段，而您试图访问第四个字段(索引 3)而不检查以验证它是否确实存在。错误在

thisRecord.setCity(fields[3]);

因为数组fields只有三个元素。在

    String[] fields = line.split(",");
    addRecordFromFields(fields);

当你到达

Patsy,Hart,661 East 11th St.

数组 fields将只创建 3 个条目。

如果希望字段数保持不变，那么您应该拒绝没有正确字段数的输入行。如果字段的数量可以变化，那么您必须检查返回的实际数量并仅提取那些实际存在的元素。