//根据查询条件查询消息列表 public List<Message> queryMessageList(String command,String description){ List<Message> messageList = new ArrayList<Message>(); try { Class.forName("com.mysql.jdbc.Driver");//1.加载数据库驱动 Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/micro_message", "root", "root");//2.获取连接对象 StringBuilder sql = new StringBuilder("select ID,COMMAND,DESCRIPTION,CONTENT from message where 1=1"); List<String> paramList = new ArrayList<String>(); //拼接sql语句 if(command!=null&&!"".equals(command.trim())){ sql.append(" and COMMAND=?"); paramList.add(command); } if(description!=null&&!"".equals(description.trim())){ sql.append(" and DESCRIPTION like ‘%‘ ? ‘%‘");//mysql字符串拼接用空格拼,传进占位符处的参数和%拼接到一块 paramList.add(description); } //3.预编译SQL语句 PreparedStatement statement = conn.prepareStatement(sql.toString()); //4.填充占位符 for(int i = 0;i < paramList.size(); i++){ statement.setString(i+1,paramList.get(i)); } //5.查询数据库 ResultSet rs = statement.executeQuery(); //6.遍历出所有数据 while(rs.next()){ Message message = new Message(); messageList.add(message); message.setId(rs.getString("ID")); message.setCommand(rs.getString("COMMAND")); message.setDescription(rs.getString("DESCRIPTION")); message.setContent(rs.getString("CONTENT")); } } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); }catch (SQLException e){ e.printStackTrace(); } return messageList; }
原文地址:https://www.cnblogs.com/wangxiaochao/p/9314108.html
时间: 2024-10-04 16:20:41