Question

我想显示数据库中的所有图像。我编写了代码但是显示错误java.sql.SQLException：列索引超出范围，0＆lt; 1.下面是我的数据库表

| application_name | varchar(45)  | 
| application_id   | varchar(10)  | 
| application_path | varchar(500) | 
| application_icon | blob         |

我想只显示images.below是我的servlet代码

IconDownload.java

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
            response.setContentType("image/jpeg");
            PrintWriter out=response.getWriter();
            try {
                Connection connection= DBUtil.getConnection();
                PreparedStatement preparedStatement=connection.prepareStatement("select application_icon  from application_master");
                ResultSet resultSet=preparedStatement.executeQuery();
                System.out.println("resultSet"+resultSet);
                out.print("<h1>photo</h1>");
                while (resultSet.next()) {
                    out.print("<img width='200' height='200' src="+resultSet.getBlob(0)+ ">  </img>" );
}
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

Answer 1

列索引应从1开始而不是0

http://docs.oracle.com/javase/7/docs/api/java/sql/ResultSet.html#getBlob(int)

参数：columnIndex - 第一列为1，第二列为2，...

应该是

resultSet.getBlob(1) //first column

Answer 2

声明应该是这样的

while（resultSet.next（））

resultSet.getBlob（1）;

col index从1到...

Answer 3

Blob getBlob(int columnIndex)
             throws SQLException
Retrieves the value of the designated column in the current row of this ResultSet object as a Blob object in the Java programming language.
Parameters:
columnIndex - the first column is 1, the second is 2, ...
Returns:
a Blob object representing the SQL BLOB value in the specified column

您尝试按索引0访问列，而枚举以1

开头

java.sql.SQLException：列索引超出范围，0＆lt; 1

IconDownload.java

3 个答案: