在executeUpdate的Prepared语句中引发异常

Question

MySQLdb mySQLdb =new MySQLdb();
    query="INSERT  INTO user(username,password,firstname,email) VALUES (?,?,?,?)";
    System.out.println(user.getUsername()+"  "+user.getPassword()+" "+user.getName()+" "+user.getEmail());
    connection= mySQLdb.getConnection();
    try {

        preparedStatement=connection.prepareStatement(query);

        preparedStatement.setString(1, user.getUsername());
        preparedStatement.setString(2, user.getPassword());
        preparedStatement.setString(3, user.getName());
        preparedStatement.setString(4, user.getEmail());
        preparedStatement.executeUpdate(query);//--->throws exception here
        //System.out.println("101");
        return true;
    } catch (Exception e) {
        System.out.println(e.getMessage());
        //System.out.println("102");
        e.printStackTrace();
    }

Errormessage:

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 '?,?,?,?)' at line 1
java.sql.SQLException: 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 '?,?,?,?)' at line 1
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2928)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)

help me to solve this issue

Answer 1

不带参数调用executeUpdate ：

preparedStatement.executeUpdate();

Answer 2

Already you have set a query parameter at

preparedStatement=connection.prepareStatement(query);
                                                ^Here

So instead calling this

preparedStatement.executeUpdate(query);

Remove the query parameter in executeUpdate();

And make it as

preparedStatement.executeUpdate();

Answer 3

do not pass the query string in executeUpdate() It will solve your issue because when you pass the parameter it calls the Statement's executeUpdate() function (ie) statement.excuteUpdate(Query);

For PreparedStatement---> preparedStatement.executeUpdate();