Can't insert byte[] into MySQL using java

问题:

Following is the code I have used:

byte[] bkey = key.getEncoded();
String query = "INSERT INTO keytable (name, key) VALUES (?,?)";
PreparedStatement pstmt = (PreparedStatement) connection.prepareStatement(query);
pstmt.setString(1, "test");
pstmt.setBytes(2, bkey);
pstmt.execute();

And following is an error I got:

com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'key) VALUES ('test',_binary'?ʾ??s??u\'?}p?u')' at line 1

I have MySQL 5.0.41 and mysql-connector-java-5.1.7-bin.jar as JDBC library. Is anyone can help me out here? Thanks in advance!

回答1:

The problem is that your column called "key" is a reserve word in SQL. Surround it with backticks and things should work. Better yet, consider renaming the column to something that is not a SQL reserve word. I've proven this out using the code below:

MySQL table:

create table keytable (name varchar(255) not null, `key` blob not null);

Java code:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class MySQLBlobInsert {

    public static void main(String[] args) {
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        Connection conn = null;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
            byte[] bkey = "This is some binary stuff".getBytes();
            String query = "INSERT INTO keytable (name, `key`) VALUES (?,?)";
            PreparedStatement pstmt = conn.prepareStatement(query);
            pstmt.setString(1, "test");
            pstmt.setBytes(2, bkey);
            pstmt.execute();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            if (conn != null) {
                try { conn.close(); } catch (SQLException e) {}
            }
        }
        System.out.println("done :)");
    }
}

回答2:

Try using "setBinaryStream()" instead of "setBytes()", and pass it a ByteArrayInputStream constructed on your byte array. This, of course, assumes that the data type assigned to the column can store bytes... Make sure it is a BLOB, BINARY, or VARBINARY.

Also, use backticks to enclose your objects. "key" is a SQL keyword, and other than that it is just a good habit:

String query = "INSERT INTO `keytable` (`name`, `key`) VALUES (?,?)";

回答3:

You should add a binary stream. Do you have access to the inputstream ?? like this..

FileInputStream input = new FileInputStream("myfile.gif");
String query = "INSERT INTO `keytable` (`name`, `key`) VALUES (?,?)";
PreparedStatement pstmt = (PreparedStatement) connection.prepareStatement(query);
pstmt.setString(1, "test");
pstmt.setBinaryStream(2, input, input.available());