java - JDBC MySQL 查询错误？

Question

我试图将一些数据插入到 mysql 数据库中，但出现错误，而且我无法通过代码找到错误。我不擅长mysql。

String insertQuery = "insert into books(title, author, description, prize)values("
            + title
            + ","
            + author
            + ","
            + desc
            + ", "
            + prize
            +  ");";

mysql> describe books;
+-------------+--------------+------+-----+---------+-------+
| Field       | Type         | Null | Key | Default | Extra |
+-------------+--------------+------+-----+---------+-------+
| book_id     | int(11)      | NO   | PRI | NULL    |       |
| title       | varchar(64)  | YES  |     | NULL    |       |
| author      | varchar(64)  | YES  |     | NULL    |       |
| description | varchar(500) | YES  |     | NULL    |       |
| prize       | float        | YES  |     | NULL    |       |
| added       | datetime     | YES  |     | NULL    |       |
+-------------+--------------+------+-----+---------+-------+
6 rows in set (0.01 sec)

我得到的错误是，

Query: insert into books(title, author, description, prize)values(sfdfdf,fdfdf,Please    limiasasaat your response to 500 characters., 78.9);
com.mysql.jdbc.exceptions.jdbc4.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 'limiasasaat your response to 500 characters., 78.9)' at line 1

Answer 1

您的字符串值没有用单引号引起来。试试这个:

String insertQuery = "insert into books(title, author, description, prize)values('"
            + title
            + "','"
            + author
            + "','"
            + desc
            + "', "
            + prize
            +  ");";

Example of Prepared Statement at RoseIndia

更新 1

PreparedStatement 示例:

//other codes here
String iSQL = "Insert into books(title, author, description, prize) values (?,?,?,?)";
// con is your active connection object
PreparedStatement pstmt = con.prepareStatement(iSQL);
pstmt.setString(1, title);
pstmt.setString(2, author);
pstmt.setString(3, desc);
pstmt.setFloat(4, prize);
pstmt.executeUpdate();
//other codes here

但不要忘记在您的类(class)顶部添加以下声明:import java.sql.*;