java.sql.SQLException:没有为参数5指定值,但字符串长度为4,而不是5

Question

我计划使用雅虎财务csv api生成网址,以获得股票实时价格和时间.该网址如下http://download.finance.yahoo.com/d/quotes.csvs=%40%5YHOO,GOOG,MSFT,BAC&f=nsl1o&e=.csv,它返回一个包含4列的表格.

我使用jdbc将数据存储到Mysql,但始终存在错误:"没有为参数5指定值".代码如下:public class Quote_Saver {private void connection(){try {Class.forName("com.mysql.jdbc.Driver"); } catch(ClassNotFoundException e){e.printStackTrace(); }}

private String retrieveQuote() {
    StringBuffer buf = new StringBuffer();
    try {
        URL page = new URL("http://download.finance.yahoo.com/d/quotes.csv?s=%40%5YHOO,GOOG,MSFT,BAC&f=nsl1o&e=.csv");
        String line;
        URLConnection conn = page.openConnection();
        conn.connect();
        InputStreamReader in = new InputStreamReader(conn.getInputStream());
        BufferedReader data = new BufferedReader(in);
        while ((line = data.readLine()) != null) {
            buf.append(line + "\n");
        }
    } catch (MalformedURLException mue) {
        System.out.println("Bad URL: " + mue.getMessage());
    } catch (IOException ioe) {
        System.out.println("IO Error:" + ioe.getMessage());
    }
    return buf.toString();
}

//use the retrieveQuote class , pass it to data in ConnectionToMysql
private void ConnectionToMysql(String data){
    StringTokenizer tokens = new StringTokenizer(data, ",");
    String[] fields = new String[4];
    for (int i = 0; i < fields.length; i++) {
        fields[i] = stripQuotes(tokens.nextToken());
    }

    connection();
    String host ="jdbc:mysql://localhost/yahoo";
    String username = "root";
    String password = ".....";
    try {
        Connection connection = DriverManager.getConnection(host, username, password);
        String query = "insert into `stocks`(?,?,?,?) values (?,?,?,?);";
        PreparedStatement statement = (PreparedStatement) connection.prepareStatement(query);
        statement.setString(1, fields[0]);
        statement.setString(2, fields[1]);
        statement.setString(3, fields[2]);
        statement.setString(4, fields[3]);
        statement.executeUpdate();
        connection.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

private String stripQuotes(String input) {
    StringBuffer output = new StringBuffer();
    for (int i = 0; i < input.length(); i++) {
        if (input.charAt(i) != '\"') {
            output.append(input.charAt(i));
        }
    }
    return output.toString();
}

public static void main (String args[])
{
    Quote_Saver qd= new Quote_Saver();
    String data = qd.retrieveQuote();
    qd.ConnectionToMysql(data);
}

}

错误是

java.sql.SQLException: No value specified for parameter 5
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1086)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)
at com.mysql.jdbc.PreparedStatement.checkAllParametersSet(PreparedStatement.java:2594)
at com.mysql.jdbc.PreparedStatement.fillSendPacket(PreparedStatement.java:2569)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2415)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2366)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2350)
at Quote_Saver.ConnectionToMysql(Quote_Saver.java:68)
at Quote_Saver.main(Quote_Saver.java:89)

但显然,字符串字段的大小只有4,我的表列也是如此,所以我的问题是参数5在哪里？以及如何解决这个问题？我是java的新手,请帮助我.非常感谢!

Answer 1

实际上,你只是犯了一个小错误 - 可能是一个复制粘贴错误.

以下行需要8个参数而不是4个,因为您将问号放在应该放置列名的位置.

insert into `stocks`(?,?,?,?) values (?,?,?,?);";

如果您按如下方式修改它(用库表中的真实名称替换列名称),那么它应该按照您的预期运行.

insert into stocks(ColumnNameOne, ColumnNameTwo, ColumnNameThree, ColumnNameFour)
values (?, ?, ?, ?);