smmessage.java

计算机技术的快速发展

/*
 * 创建日期 2005-5-8
 */
package com.suninformation.schoolmate;

import java.sql.*;

import com.suninformation.database.*;
import com.suninformation.user.*;

/**
 * @author 刘镇
 *
 * 班级留言类
 */
public class SMMessage {

  private static final String LOAD_MESSAGE_BY_MSGID = "SELECT username,messagecontent,messagetype,classid,sendtime,modifytime FROM sm_message WHERE msgid=?";

  private static final String INSERT_MESSAGE = "INSERT INTO sm_message(username,classid,messagecontent,messagetype,modifytime,sendtime) VALUES(?,?,?,?,?,?)";

  private static final String SAVE_MESSAGE = "UPDATE sm_message SET messagecontent=?,messagetype=?,modifytime=? WHERE msgid=?";

  private int msgId = -1; //留言ID

  private String userName = null; //用户名

  private String messageContent = null; //留言内容

  private int messageType = -1; //留言类型：0-普通文本;1-多彩文本;2-系统信息;3-...

  private int classId = -1; //所属班级ID

  private Date sendTime = null; //发表时间

  private Date modifyTime = null; //修改时间

  private boolean isChanged = false; //已修改标记

  /**
   * @return 返回 messageContent。
   */
  public String getMessageContent() {
    return messageContent;
  }

  /**
   * @param messageContent
   *            要设置的 messageContent。
   */
  public void setMessageContent(String messageContent) {
    this.messageContent = messageContent;
    this.isChanged = true;
  }

  /**
   * @return 返回 messageType。
   */
  public int getMessageType() {
    return messageType;
  }

  /**
   * @param messageType
   *            要设置的 messageType。
   */
  public void setMessageType(int messageType) {
    this.messageType = messageType;
    this.isChanged = true;
  }

  /**
   * @return 返回 modifyTime。
   */
  public Date getModifyTime() {
    return modifyTime;
  }

  /**
   * @param modifyTime
   *            要设置的 modifyTime。
   */
  public void setModifyTime(Date modifyTime) {
    this.modifyTime = modifyTime;
    this.isChanged = true;
  }

  /**
   * @return 返回 userName。
   */
  public String getUserName() {
    return userName;
  }

  /**
   * @return 返回 classId。
   */
  public int getClassId() {
    return classId;
  }

  /**
   * @return 返回 sendTime。
   */
  public Date getSendTime() {
    return sendTime;
  }


  public int getMsgId() {
    return msgId;
  }

  ///////////////////////////////////////////////////////////////////
  ///////////////////////////////////////////////////////////////////

  public SMMessage(int msgid) throws SMMessageNotFoundException,
      UnacceptableException {
    this.msgId = msgid;
    loadFromDB();
  }

  public SMMessage(String msgcontent, int msgtype, String username,
                   int classid) throws SMMessageAlreadyExistsException,
      UnacceptableException {
    this.messageContent = msgcontent;
    this.messageType = msgtype;
    this.userName = username;
    this.classId = classid;
    this.sendTime = new Date(System.currentTimeMillis());
    this.modifyTime = this.sendTime;
    insertIntoDB();
  }

  /**
   * 读取班级留言信息
   *
   * @throws SMMessageNotFoundException
   * @throws UnacceptableException
   */
  private void loadFromDB() throws SMMessageNotFoundException,
      UnacceptableException {
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = DBManager.getConnection();
      pstmt = conn.prepareStatement(LOAD_MESSAGE_BY_MSGID);
      pstmt.setInt(1, this.msgId);
      rs = pstmt.executeQuery();
      if (!rs.next()) {
        throw new SMMessageNotFoundException("班级" + this.classId
                                             + "留言“" + this.msgId + "”不存在。");
      }
      this.userName = rs.getString(1);
      this.messageContent = rs.getString(2);
      this.messageType = rs.getInt(3);
      this.classId = rs.getInt(4);
      this.sendTime = rs.getDate(5);
      this.modifyTime = rs.getDate(6);
    }
    catch (SQLException sqle) {
      throw new UnacceptableException("读取成员数据失败。", sqle);
    }
    finally {
      DBManager.closeObject(conn, pstmt, rs);
    }
  }

  /**
   * 添加新成员操作
   *
   * @throws SMMessageAlreadyExistsException
   * @throws UnacceptableException
   */
  private void insertIntoDB() throws SMMessageAlreadyExistsException,
      UnacceptableException {
/*    try {
      SMMessage[] smm = (new SMClass(this.classId)).getSMMeaages();
      if (smm != null) {
        for (int i = 0; i < smm.length; i++) {
          if (this.messageContent.equals(smm[i].getMessageContent()) && this.userName.equals(smm[i].getUserName())) {
            throw new SMMessageAlreadyExistsException(
                "留言已存在!");
          }
        }
      }
    }
    catch (SMClassNotFoundException smce) {
      throw new UnacceptableException("没有找到参数所指定的班级ID", smce);
    }*/
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = DBManager.getConnection();
      pstmt = conn.prepareStatement(INSERT_MESSAGE);
      pstmt.setString(1, this.userName);
      pstmt.setInt(2, this.classId);
      pstmt.setString(3, this.messageContent);
      pstmt.setInt(4, this.messageType);
      pstmt.setDate(5, this.modifyTime);
      pstmt.setDate(6, this.sendTime);
      pstmt.executeUpdate();
    }
    catch (SQLException e) {
      throw new UnacceptableException("写入留言数据失败.", e);
    }
    finally {
      DBManager.closeObject(conn, pstmt, rs);
    }
  }

  /**
   * 保存数据到DB
   *
   */
  private void saveToDB() throws UnacceptableException {
    Connection conn = null;
    try {
      conn = DBManager.getConnection();
      saveToDB(conn);
    }
    catch (SQLException sqle) {
      throw new UnacceptableException("保存数据出错", sqle);
    }
    finally {
      try {
        conn.close();
      }
      catch (Exception e) {
        e.printStackTrace();
      }
    }
  }

  /**
   * 保存数据库到DB
   *
   * @param con
   * @throws SQLException
   */
  private void saveToDB(Connection con) throws SQLException {
    PreparedStatement pstmt = null;
    try {
      pstmt = con.prepareStatement(SAVE_MESSAGE);
      pstmt.setString(1, this.messageContent);
      pstmt.setInt(2, this.messageType);
      pstmt.setDate(3, this.modifyTime);
      pstmt.setInt(4, this.msgId);
      pstmt.executeUpdate();
    }
    finally {
      try {
        pstmt.close();
      }
      catch (Exception e) {
        e.printStackTrace();
      }
    }
  }

  /**
   * 保存信息修改；当对该类的属性进行更改后，可以使用该方法进行写入数据库操作。
   *
   */
  public void save() {
    if (this.isChanged) {
      try {
        this.modifyTime = new Date(System.currentTimeMillis());
        saveToDB();
      }
      catch (UnacceptableException ue) {
      }

    }
  }
}