问题描述
在验证我选择的选择组合框后，我无法将其插入到我的数据库中.Tomcat 出现以下错误:
After validation of select combo box which I have selected and I am not able to insert it in my database. Tomcat gives following error:
java.sql.SQLException: 参数索引超出范围(1 > 参数数量，为 0).
这是怎么引起的，我该如何解决?
How is this caused and how can I solve it?
推荐答案
当您调用 PreparedStatement 上的任何 setXxx() 方法时，您将收到此错误，而SQL 查询字符串没有任何占位符 ? 用于此.
You will get this error when you call any of the setXxx() methods on PreparedStatement, while the SQL query string does not have any placeholders ? for this.
例如这是错误:
String sql = "INSERT INTO tablename (col1, col2, col3) VALUES (val1, val2, val3)";
// ...
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, val1); // Fail.
preparedStatement.setString(2, val2);
preparedStatement.setString(3, val3);
您需要相应地修复 SQL 查询字符串以指定占位符.
You need to fix the SQL query string accordingly to specify the placeholders.
String sql = "INSERT INTO tablename (col1, col2, col3) VALUES (?, ?, ?)";
// ...
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, val1);
preparedStatement.setString(2, val2);
preparedStatement.setString(3, val3);
注意参数索引以 1 开头，并且您不需要像这样引用这些占位符:
Note the parameter index starts with 1 and that you do not need to quote those placeholders like so:
String sql = "INSERT INTO tablename (col1, col2, col3) VALUES ('?', '?', '?')";
否则你仍然会得到同样的异常，因为 SQL 解析器会将它们解释为实际的字符串值，因此无法再找到占位符.
Otherwise you will still get the same exception, because the SQL parser will then interpret them as the actual string values and thus can't find the placeholders anymore.
这篇关于java.sql.SQLException 参数索引超出范围(1 > 参数个数，为0)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！