Question

我正在开发一个电子邮件数据库程序，当我尝试将电子邮件存储到数据库中时，我仍然遇到语法错误，而且我不确定它为什么会发生。我以完全相同的方式存储用户对象，虽然它确实将用户对象存储到数据库中，但它最终更新了我的数据库中的某些值，而不是在退出程序并再次测试程序时插入新值。语法错误可能来自我的一些列存储Blob的事实吗？

MYSQL：

 'CREATE TABLE `item` (\n  `Id` int(10) unsigned NOT NULL DEFAULT \'0\',\n  `To`               varchar(300) NOT NULL COMMENT \'To\',\n  `From` varchar(300) NOT NULL,\n  `Subject` varchar(45) NOT NULL COMMENT \'subject\',\n  `topic` varchar(45) NOT NULL COMMENT \'category\',\n  `Email_Content` blob NOT NULL COMMENT \'Email Content may change\',\n  `Comments` blob,\n  `Attachments` blob,\n  PRIMARY KEY (`Id`)\n) ENGINE=InnoDB DEFAULT    CHARSET=utf8'

数据库类：

public void storeItem() throws SQLException{
    String checkSql = "select count(*) as count from item where Id=?";
    PreparedStatement checkStatement = con.prepareStatement(checkSql);

    String storeSql = "insert into item(Id, To, From, Subject, topic, Email_Content, Comments, Attachments) values(?,?,?,?,?,?,?,?)";
    PreparedStatement insertStatement = con.prepareStatement(storeSql);

    String updateSql = "insert into set To=? From=?, Subject=?, topic=?, Email_Address=?, Comments=?, Attachments=? where Id=?";
    PreparedStatement updateStatement = con.prepareStatement(updateSql);

    for(Item items: Items){
        int ItemId = items.getId();
        String To = items.getTo();
        String From = items.getFrom();
        String Subject = items.getSubject();
        String Topic = items.getTopic();
        String Email = items.getMessageContent();
        String Comments = items.getComments();
        String attachments = items.getAttachments();

        checkStatement.setInt(1, ItemId);
        ResultSet checkResult = checkStatement.executeQuery();
        checkResult.next();
        int count = checkResult.getInt(1);

        if (count == 0) {
            System.out.println("Inserting person with ID " + ItemId);
            int col = 1;
            insertStatement.setInt(col++, ItemId);
            insertStatement.setString(col++, To);
            insertStatement.setString(col++, From);
            insertStatement.setString(col++, Subject);
            insertStatement.setString(col++, Topic);
            insertStatement.setString(col++, Email);
            insertStatement.setString(col++, Comments);
            insertStatement.setString(col++, attachments);
            insertStatement.executeUpdate();

        } else {
            System.out.println("Updating person with ID " + ItemId);
            int col = 1;
            updateStatement.setString(col++, To);
            updateStatement.setString(col++, From);
            updateStatement.setString(col++, Subject);
            updateStatement.setString(col++, Topic);
            updateStatement.setString(col++, Email);
            updateStatement.setString(col++, Comments);
            updateStatement.setString(col++, attachments);
            updateStatement.setInt(col++, ItemId);

            updateStatement.executeUpdate();
        }

         System.out.println("Count for person with ID " + ItemId + " is " + count);
    }
    updateStatement.close();
    insertStatement.close();
    checkStatement.close();


}

控制器类

    public void storeItem() throws SQLException{
    dc.storeItem();
}

MainFrame类

public void completeEventOccurred() {
            if (LoadEmailPanel.getComplete() == true) {
                String To = LoadEmailPanel.getText(1);
                String From = LoadEmailPanel.getText(2);
                String Subject = LoadEmailPanel.getText(3);
                String Topic = LoadEmailPanel.getText(4);
                String Email = LoadEmailPanel.getText(5);
                String Notes = LoadEmailPanel.getText(6);
                String Attach = LoadEmailPanel.getText(7);

                EmailEvent ev = new EmailEvent(this, To, From, Subject,
                        Topic, Email, Notes, Attach);
                controller.addEmail(ev);
                connect();
                try {
                    controller.storeItem();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }



                cards.show(MainFrame.this.getContentPane(), "Home");
            }
        }

    });

Answer 1

JOptionPane.showMessageDialog(null,query);

这将帮助您在查询中找到语法错误在查询中使用单引号和双引号组合

insertQuery =“Insert Into TableName（Name，EnrollmentNo，Country）值（”+“'”+ Mack“'，”+ 12103596“，”“+ India +”'）“;

在我的java代码中不断收到mysql语法错误？

1 个答案: