MySQL 插入查询中提到的 Java Array 元素未插入到表中。而是抛出错误

Posted 2023-02-25

【中文标题】MySQL 插入查询中提到的 Java Array 元素未插入到表中。而是抛出错误

【英文标题】：Java Array element mentioned in MySQL insertion query not getting inserted into table .Instead an error is being thrown

【发布时间】：2019-03-23 11:29:21

【问题描述】：

我从用户那里获取值，例如：姓名、地址、电话号码、城市、目的地、日期

这些值中的每一个都存储在它们各自的数组中。在进入数组的下一次迭代之前，我想将数组元素插入到 mysql 表中 .我为此使用 JDBC。但是，我看到了 SQL 查询不正确的错误：

这是我的 SQL 查询：

String sql = "INSERT INTO `registration`(`phone`, `name`, `address`, `city`, `destination`, `date`) VALUES (100,name[i],address[i],city[i],destination[i],date[i])";

这是我正在执行 SQL 查询的相关代码部分

 case 1: 
                        System.out.println("Enter your Phone number:");
                        phone[i] = sc.nextInt();
                        sc.nextLine();

                        System.out.println("Enter your name:");
                        name[i] = sc.nextLine();


                        System.out.println("Enter your address:");
                        address[i] = sc.nextLine();

                        System.out.println("Enter your Pick up city:");
                        city[i] = sc.nextLine();


                        System.out.println("Enter your Destination:");
                        destination[i] = sc.nextLine();


                        System.out.println("Enter your Date:");
                        date[i] = sc.nextLine();
                        ++i;
                        Connection conn = null;
                        Statement stmt = null;
                        try
                            //STEP 2: Register JDBC driver
                            Class.forName("com.mysql.jdbc.Driver");

                            //STEP 3: Open a connection
                            System.out.println("Connecting to a selected database...");
                            conn = DriverManager.getConnection(DB_URL, USER, PASS);
                            System.out.println("Connected database successfully...");

                            //STEP 4: Execute a query
                            System.out.println("Inserting records into the table...");
                            stmt = conn.createStatement();
                            String sql = "INSERT INTO `registration`(`phone`, `name`, `address`, `city`, `destination`, `date`) VALUES (100,name[i],address[i],city[i],destination[i],date[i])";
                            stmt.executeUpdate(sql);

                        catch(SQLException se)
                            //Handle errors for JDBC
                            se.printStackTrace();
                        catch(Exception e)
                            //Handle errors for Class.forName
                            e.printStackTrace();
                        finally
                            //finally block used to close resources
                            try
                                if(stmt!=null)
                                    conn.close();
                            catch(SQLException se)
                            // do nothing
                            try
                                if(conn!=null)
                                    conn.close();
                            catch(SQLException se)
                                se.printStackTrace();
                            //end finally try
                        //end try
                        System.out.println("Goodbye!");
                        break;
                    

这是显示的错误：

这是我在上面代码中的 SQL 查询

 com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '[i],address[i],city[i],destination[i],date[i])' at line 1
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
        at com.mysql.jdbc.Util.getInstance(Util.java:387)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:942)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3966)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3902)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2545)
        at com.mysql.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1540)
        at com.mysql.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2595)
        at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1468)
        at Airplane.main(Airplane.java:74)

我做错了什么？

【问题讨论】：

大错特错。 1）不要将表名和列名放在引号中。 2）查找如何在准备好的语句中添加参数。

【参考方案1】：

首先，您最好使用PreparedStatement 来实现某种程度的类型安全和对SQL 注入的保护。 PreparedStatement 还允许以批处理模式插入多行，从而提高性能。

您只需在循环之外创建一次PreparedStatement 对象。

PreparedStatement stmt = conn.prepareStatement("INSERT INTO `registration`(`phone`, `name`, `address`, `city`, `destination`, `date`) VALUES (100,?,?,?,?,?)");
stmt.setString(1, name[i]);
stmt.setString(2, address[i]);
stmt.setString(3, city[i]);
stmt.setString(4, destination[i]);
stmt.setString(5, date[i]);