Android CSV 解析器问题

Question

我在解析 CSV 文件时遇到问题。它只有 2 行数据，用逗号分隔。第一行是日期，第二行是值。日期字段将始终包含日期，但有时该值为空白（或 null？）。当它达到空值时，我得到一个 StringIndexOutOfBoundsException 并且应用程序崩溃。我正在记录每个循环并且可以看到数据，但是一旦我达到空值，它就会停止循环并给出错误。如果没有空值，那么它就完美了。这是我的代码：

        BufferedReader buf = new BufferedReader(new StringReader(file));
        String line = null;
        while ((line = buf.readLine()) != null) {
            try {
                String date = null, value = null;
                String[] RowData = line.split(",");
                date = RowData[0];
                value = RowData[1]; (this is the row it crashes on)

这是 CSV 的样子：

2011-08-28 09:16,8.23

2011-08-28 09:15,8.24

2011-08-28 09:14,8.26

2011-08-28 09:13,8.34

2011-08-28 09:12,

2011-08-28 09:11,10.72

2011-08-28 09:10,

2011-08-28 09:09,

09:13 的值是我收到错误之前 logcat 中的最后一件事。

这解决了它：

                if(RowData.length == 2) {
                    date = RowData[0];
                    value = RowData[1];
                } else {
                    date = RowData[0];
                    value = "0";
                }

我在 value 字段中写了一个 0，这样以后的进程就不会被 null 值阻塞。感谢大家的帮助！

Answer 1

你想做这个或类似的事情：

String date = null, value = null;
String[] RowData = line.split(",");
date = RowData[0];

if(RowData.length ==2)value = RowData[1]; (this is the row it crashes on)

或者它的一些变体，例如if(RowData.length

Answer 2

既然您可以使用已经编写好的库来为您完成解析，为什么还要编写自己的 CSV 解析？或许OpenCSV 会帮助您实现 CSV 解析目标。

Answer 3

在尝试访问之前检查 RowData 的长度。看起来 split() 正在返回一个包含单个对象的数组，但您正在尝试访问第二个对象，这确实超出了范围。

Answer 4

public class CityParser {
    DocumentBuilderFactory factory;
    DocumentBuilder builder;
    Document doc;

    Element ele;

    int mediaThumbnailCount;`enter code here`
    boolean urlflag;
    CityListBean objBean = null;

    Vector<CityListBean> vecCityList;

    public CityParser() {

    }

    public Vector<CityListBean> getCityData() {

        vecCityList = new Vector<CityListBean>();
        try {
            HttpClient httpClient = new DefaultHttpClient();
            HttpContext localContext = new BasicHttpContext();
            HttpGet httpGet = new HttpGet(
                    "http://heresmyparty.com/cms/index.php?option=com_chronocontact&chronoformname=add_event_form_download");
            HttpResponse response = httpClient.execute(httpGet, localContext);
            // String result = "";

            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    response.getEntity().getContent()));

            CSVReader csvreader = new CSVReader(reader);
            String[] nextLine;
            while ((nextLine = csvreader.readNext()) != null) {

                CityListBean objcitylist = new CityListBean();
                // nextLine[] is an array of values from the line
                objcitylist.setText_title(nextLine[5]);
                objcitylist.setText_host(nextLine[6]);
                objcitylist.setText_price(nextLine[7]);
                objcitylist.setDate(nextLine[8]);
                objcitylist.setText_venue(nextLine[11]);
                objcitylist.setAddress(nextLine[12]);
                objcitylist.setLatitude(nextLine[13]);
                objcitylist.setLongitude(nextLine[14]);
                objcitylist.setFile(nextLine[15]);
                objcitylist.setText_description(nextLine[16]);
                objcitylist.setCity(nextLine[17]);
                vecCityList.addElement(objcitylist);

            }


              /*for (int i = 0; i < vecCityList.size(); i++) { CityListBean
              objcity = (CityListBean) vecCityList.get(i);

              System.out.println("Cf_id : " + objcity.getCityName());
              System.out.println("-----------------------------------"); }*/


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

        return vecCityList;
    }
}

==========================================================================================

public class CSVReader {

    private BufferedReader br;

    private boolean hasNext = true;

    private char separator;

    private char quotechar;

    private int skipLines;

    private boolean linesSkiped;


    public static final char DEFAULT_SEPARATOR = ',';

    public static final char DEFAULT_QUOTE_CHARACTER = '"';

    public static final int DEFAULT_SKIP_LINES = 0;

    public CSVReader(Reader reader) {
        this(reader, DEFAULT_SEPARATOR, DEFAULT_QUOTE_CHARACTER,
            DEFAULT_SKIP_LINES);
    }

    public CSVReader(Reader reader, char separator, char quotechar, int line) {
        this.br = new BufferedReader(reader);
        this.separator = separator;
        this.quotechar = quotechar;
        this.skipLines = line;
    }

    public String[] readNext() throws IOException {

        String nextLine = getNextLine();
        return hasNext ? parseLine(nextLine) : null;
    }

    private String getNextLine() throws IOException {
        if (!this.linesSkiped) {
            for (int i = 0; i < skipLines; i++) {
                br.readLine();
            }
            this.linesSkiped = true;
        }
        String nextLine = br.readLine();
        if (nextLine == null) {
            hasNext = false;
        }
        return hasNext ? nextLine : null;
    }

    private String[] parseLine(String nextLine) throws IOException {

        if (nextLine == null) {
            return null;
        }

        List<String> tokensOnThisLine = new ArrayList<String>();
        StringBuffer sb = new StringBuffer();
        boolean inQuotes = false;
        do {
                if (inQuotes) {
                // continuing a quoted section, reappend newline
                sb.append("\n");
                nextLine = getNextLine();
                if (nextLine == null)
                    break;
            }
            for (int i = 0; i < nextLine.length(); i++) {

                char c = nextLine.charAt(i);
                if (c == quotechar) {
                        // this gets complex... the quote may end a quoted block, or escape another quote.
                        // do a 1-char lookahead:
                        if( inQuotes  // we are in quotes, therefore there can be escaped quotes in here.
                            && nextLine.length() > (i+1)  // there is indeed another character to check.
                            && nextLine.charAt(i+1) == quotechar ){ // ..and that char. is a quote also.
                                // we have two quote chars in a row == one quote char, so consume them both and
                                // put one on the token. we do *not* exit the quoted text.
                                sb.append(nextLine.charAt(i+1));
                                i++;
                        }else{
                                inQuotes = !inQuotes;
                                // the tricky case of an embedded quote in the middle: a,bc"d"ef,g
                                if(i>2 //not on the begining of the line
                                                && nextLine.charAt(i-1) != this.separator //not at the begining of an escape sequence
                                                && nextLine.length()>(i+1) &&
                                                nextLine.charAt(i+1) != this.separator //not at the     end of an escape sequence
                                ){
                                        sb.append(c);
                                }
                        }
                } else if (c == separator && !inQuotes) {
                    tokensOnThisLine.add(sb.toString());
                    sb = new StringBuffer(); // start work on next token
                } else {
                    sb.append(c);
                }
            }
        } while (inQuotes);
        tokensOnThisLine.add(sb.toString());
        return (String[]) tokensOnThisLine.toArray(new String[0]);

    }

    public void close() throws IOException{
        br.close();
    }

}

Answer 5

你有没有试过先检查

if (RowData[1]!=null) or possibly if (RowData[1]!="") 

我不明白为什么这会导致您的应用崩溃， 它应该将值设置为 null 或 ""