String.charAt 的 StringIndexOutOfBoundsException 错误 [重复]

Question

我创建了一个关于从网页获取元素的 java 应用程序，这是代码。

public class rpms {

    public rpms() {

    }

    private static final String USER_AGENT = "Mozilla/5.0";
    private static final String URL ="https://url.com";

    public static void main(String[] args) {
        URLget labaccess = new URLget();

        try {
            getElementTd(sendGetRequest(URL).toString());
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static String sendGetRequest(String urlString) throws IOException {

        URL obj = new URL(urlString);
        HttpURLConnection httpConnection = (HttpURLConnection) obj
                .openConnection();

        httpConnection.setRequestMethod("GET");

        httpConnection.setRequestProperty("User-Agent", USER_AGENT);

        int responseCode = httpConnection.getResponseCode();
        if (responseCode == 200) {

            BufferedReader responseReader = new BufferedReader(
                    new InputStreamReader(httpConnection.getInputStream()));

            String responseLine;
            StringBuffer response = new StringBuffer();

            while ((responseLine = responseReader.readLine()) != null) {
                response.append(responseLine + "\n");
            }
            responseReader.close();

            // print result
            return response.toString();
        }
        return null;
    }

    public static void getElementTd(String sourceCode)
            throws FileNotFoundException, UnsupportedEncodingException {
        String fragment = sourceCode;
        ArrayList<String> ip = new ArrayList<String>();
        Document doc = Jsoup.parseBodyFragment(fragment);

        Elements elements = doc.select("td p");

        for (int i = 0; i < elements.size(); i++) {
            // System.out.println(i+1+" ) "+elements.eq(i).text().toString());

            if (fileExplode(elements.eq(i).text().toString())) {
                System.out.println(elements.eq(i).text().toString());

            }
        }
    }

    public static boolean fileExplode(String str1) {
        boolean hasRPM = false;
        String[] split1 = str1.replace(".", " ").split(" ");

        for (int i = 0; i < split1.length; i++) {
            if ((i + 1) == split1.length) {
                if (split1[i].equalsIgnoreCase("rpm")
                        || (split1[i].charAt(0) == 'r'
                                && split1[i].charAt(1) == 'p' && split1[i]
                                .charAt(2) == 'm')) {
                    hasRPM = true;

                }break;
            }

        }
        return hasRPM;
    }   
}

但是当我执行上面的代码时。发生错误：线程“main”中的异常我不知道这是什么意思。 charAt 出错。

 Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 0
 at java.lang.String.charAt(Unknown Source)
 at rpms.fileExplode(rpms.java:98)
 at rpms.getElementTd(rpms.java:82)
 at rpms.main(rpms.java:32)

为了获得更多指导，这是发生错误的数字。

/*97*/ if (split1[split1.length - 1].equalsIgnoreCase("rpm")
/*98*/|| (split1[i].charAt(0) == 'r'
/*99*/ && split1[i].charAt(1) == 'p' && split1[i]
/*100*/ .charAt(2) == 'm')) {

/*82*/ if (fileExplode(elements.eq(i).text().toString())) {
/*83*/ System.out.println(elements.eq(i).text().toString());
/*84*/ }

/*32*/ getElementTd(sendGetRequest(URL).toString());

请帮我解决发生的错误。

Answer 1

这个错误意味着你试图从一个大于或等于字符串长度的索引处的字符串中获取一个字符。具体来说，是当您尝试在第 98 行获取 split[i] 中的第一个字符时。您永远不会检查 split1[i] 的大小是否大于 0。我建议添加它。

for (int i = 0; i < split1.length; i++) {
    if ((i + 1) == split1.length) {
        if (split1[i].equalsIgnoreCase("rpm")
                || (split1[i].length > 2 && split1[i].charAt(0) == 'r'
                        && split1[i].charAt(1) == 'p' && split1[i]
                        .charAt(2) == 'm')) {
            hasRPM = true;
        }

        break;
    }
}