数据查询中文出现错误

Question

错误：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 'and COMMAND='查询'' at line 1protected void doGet(HttpServletRequest req,HttpServletResponse rsp) throws ServletException, IOException{      try {          //数据库连接        Class.forName("com.mysql.jdbc.Driver");        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mybatis_demo?"                + "useUnicode=true&characterEncoding=utf-8&user=root&password=mysql");                //页面查询参数的获取        //解决中文乱码问题        req.setCharacterEncoding("UTF-8");        rsp.setCharacterEncoding("uft-8");        String command = req.getParameter("command");        String description =req.getParameter("description");                //String sql = "select ID,COMMAND,DESCRIPTION,CONTENT from MESSAGE";        StringBuilder sql = new StringBuilder("select ID,COMMAND,DESCRIPTION,CONTENT from MESSAGE");        List<String> paramList = new ArrayList<String>();        if (command!=null && !"".equals(command.trim())) {            sql.append(" and COMMAND=? ");            paramList.add(command);        }                if (description!=null&&!"".equals(description.trim())) {            sql.append(" and DESCRIPTION like '%'?'%' ");            paramList.add(description);        }                PreparedStatement pStatement= conn.prepareStatement(sql.toString());        for (int i = 0; i < paramList.size(); i++) {            pStatement.setString(i+1, paramList.get(i));        }        ResultSet rs = pStatement.executeQuery();        List<Message> messagelist = new ArrayList<Message>();        while(rs.next()){            Message message = new Message();            message.setId(rs.getInt("ID"));            message.setCommand(rs.getString("COMMAND"));            message.setDescription(rs.getString("DESCRIPTION"));            message.setContent(rs.getString("CONTENT"));            messagelist.add(message);        }        req.setAttribute("messageList", messagelist);    } catch (ClassNotFoundException e) {        // TODO: handle exception        e.printStackTrace();    }catch (SQLException e) {        // TODO: handle exception        e.printStackTrace();    }    req.getRequestDispatcher("/WEB-INF/jsp/back/list.jsp").forward(req, rsp);          }

Answer 1

你在查询之前打印一下是不是在进入servlet之后就乱码了，