common.jsp

用JAVA实现的一个网上商城系统

<%!
//
//   Filename: Common.jsp
//   定义之后可能使用到的函数


  static final String CRLF = "\r\n";

  static final int UNDEFINT=Integer.MIN_VALUE;

  static final int adText = 1;
  static final int adDate = 2;
  static final int adNumber = 3;
  static final int adSearch_ = 4;
  static final int ad_Search_ = 5;
  static final String appPath   ="/";

//Database connection string

  static final String DBDriver  ="sun.jdbc.odbc.JdbcOdbcDriver";
  static final String strConn   ="jdbc:odbc:driver={Microsoft Access Driver (*.mdb)};DBQ=D:/BookStore_MSAccess.mdb";
  static final String DBusername="";
  static final String DBpassword="";

//载入驱动
  public static String loadDriver ()	
  {
    String sErr = "";
    try {
      java.sql.DriverManager.registerDriver((java.sql.Driver)(Class.forName(DBDriver).newInstance()));
    }
    catch (Exception e) {
      sErr = e.toString();
    }
    return (sErr);
  }

//遍历数据库
  public static void absolute(java.sql.ResultSet rs, int row) throws java.sql.SQLException	
  {
    for(int x=1;x<row;x++) rs.next();
  }

//执行SQL语句,并返回ResultSet
  java.sql.ResultSet openrs(java.sql.Statement stat, String sql) throws java.sql.SQLException	
  {
    java.sql.ResultSet rs = stat.executeQuery(sql);
    return (rs);
  }

//功能? 查是否存在书籍
  String dLookUp(java.sql.Statement stat, String table, String fName, String where) 
  {
    java.sql.Connection conn1 = null;
    java.sql.Statement stat1 = null;
    try {
      conn1 = cn();
      stat1 = conn1.createStatement();
      java.sql.ResultSet rsLookUp = openrs( stat1, "SELECT " + fName + " FROM " + table + " WHERE " + where);
      if (! rsLookUp.next()) {
        rsLookUp.close();
        stat1.close();
        conn1.close();
        return "";
      }
      String res = rsLookUp.getString(1);	//res存储第一行的第一列值
      rsLookUp.close();
      stat1.close();
      conn1.close();
      return (res == null ? "" : res);
    }
    catch (Exception e) {
      return "";
    }
  }

//查询记录数
  long dCountRec(java.sql.Statement stat, String table, String sWhere) 
  {
    long lNumRecs = 0;
    try {
      java.sql.ResultSet rs = stat.executeQuery("select count(*) from " + table + " where " + sWhere);
      if ( rs != null && rs.next() ) {
        lNumRecs = rs.getLong(1);
      }
      rs.close();
    }
    catch (Exception e ) {};
    return lNumRecs;
  }

  String proceedError(javax.servlet.http.HttpServletResponse response, Exception e) 
  {
    return e.toString();
  }

//获取所有列名
  String[] getFieldsName ( java.sql.ResultSet rs ) throws java.sql.SQLException	
  {
    java.sql.ResultSetMetaData metaData = rs.getMetaData();
    int count = metaData.getColumnCount();
    String[] aFields = new String[count];
    for(int j = 0; j < count; j++) {
      aFields[j] = metaData.getColumnLabel(j+1);
    }
    return aFields;
  }

//获取列值,返回一个哈希表
  java.util.Hashtable getRecordToHash ( java.sql.ResultSet rs, java.util.Hashtable rsHash, String[] aFields ) throws java.sql.SQLException 
  {
    for ( int iF = 0; iF < aFields.length; iF++ ) {
      rsHash.put( aFields[iF], getValue(rs, aFields[iF]));
    }
    return rsHash;
  }

//连接数据库,返回Connection对象
  java.sql.Connection cn() throws java.sql.SQLException 
  {
    return java.sql.DriverManager.getConnection(strConn , DBusername, DBpassword);
  }

//转化成URL
  String toURL(String strValue)
  {
    if ( strValue == null ) return "";
    if ( strValue.compareTo("") == 0 ) return "";
    return java.net.URLEncoder.encode(strValue);
    //encode(String) 将一字符串转换成 x-www-form-urlencoded 格式。
  }

//转化成HTML语句
  String toHTML(String value) 
  {
    if ( value == null ) return "";
    value = replace(value, "&", "&amp;");
    value = replace(value, "<", "&lt;");
    value = replace(value, ">", "&gt;");
    value = replace(value, "\", "&" + "quot;");
    return value;
  }

//获取fieldName列值,返回HTML格式
  String getValueHTML(java.sql.ResultSet rs, String fieldName) 
  {
    try {
      String value = rs.getString(fieldName);
      if (value != null) {
        return toHTML(value);
      }
    }
    catch (java.sql.SQLException sqle) {}
    return "";
  }

//获取strFieldName列值,返回String型
  String getValue(java.sql.ResultSet rs, String strFieldName) 
  {
    if ((rs==null) ||(isEmpty(strFieldName)) || ("".equals(strFieldName))) return "";
    try {
      String sValue = rs.getString(strFieldName);
      if ( sValue == null ) sValue = "";
      return sValue;
    }
    catch (Exception e) {
      return "";
    }
  }

//获取请求中paramName参数值
  String getParam(javax.servlet.http.HttpServletRequest req, String paramName) 
  {
    String param = req.getParameter(paramName);
    if ( param == null || param.equals("") ) return "";
    param = replace(param,"&amp;","&");
    param = replace(param,"&lt;","<");
    param = replace(param,"&gt;",">");
    param = replace(param,"&amp;lt;","<");
    param = replace(param,"&amp;gt;",">");
    return param;
  }

//判断param是否数字
  boolean isNumber (String param) 
  {
    boolean result;
    if ( param == null || param.equals("")) return true;
    param=(param.replace('d','_')).replace('f','_');
    try {
      Double dbl = new Double(param);
      result = true;
    }
    catch (NumberFormatException nfe) {
      result = false;
    }
    return result;
  }

//判断val是否为空
  boolean isEmpty (int val)
  {
    return val==UNDEFINT;
  }

//判断val是否为空
  boolean isEmpty (String val)
  {
    return (val==null || val.equals("")||val.equals(Integer.toString(UNDEFINT))); 
  }

//获取复选框的值
  String getCheckBoxValue (String val, String checkVal, String uncheckVal, int ctype) 
  {
    if (val==null || val.equals("") ) return toSQL(uncheckVal, ctype);
    else return toSQL(checkVal, ctype);
  }

//将fieldName,fieldVal根据type类型合并成Where子句
  String toWhereSQL(String fieldName, String fieldVal, int type) 
  {
    String res = "";
    switch(type) {
      case adText: 
        if (! "".equals(fieldVal)) {
          res = " " + fieldName + " like '%" + fieldVal + "%'";
        }
      case adNumber:
        res = " " + fieldName + " = " + fieldVal + " ";
      case adDate:
        res = " " + fieldName + " = '" + fieldVal + "' ";
      default:
        res = " " + fieldName + " = '" + fieldVal + "' ";
    }
    return res;
  }

//把value根据type类型转化成SQL语句
  String toSQL(String value, int type) 
  {
    if ( value == null ) return "Null";
    String param = value;
    if ("".equals(param) && (type == adText || type == adDate) ) {
      return "Null";
    } 
    switch (type) {
      case adText: {
        param = replace(param, "'", "''");
        param = replace(param, "&amp;", "&");
        param = "'" + param + "'";
        break;
      }
      case adSearch_:
      case ad_Search_: {
        param = replace(param, "'", "''");
        break;
      }
      case adNumber: {
        try {
          if (! isNumber(value) || "".equals(param)) param="null";
          else param = value;
        }
        catch (NumberFormatException nfe) {
          param = "null";
        }
        break;
      }
      case adDate: {
        param = "'" + param + "'";
        break;      
      }
    }
    return param;
  }

//把str中pattern全部替换成replace
  private String replace(String str, String pattern, String replace) 
  {
    if (replace == null) {
      replace = "";
    }
    int s = 0, e = 0;
    StringBuffer result = new StringBuffer((int) str.length()*2);
    while ((e = str.indexOf(pattern, s)) >= 0) {
      result.append(str.substring(s, e));
      result.append(replace);
      s = e + pattern.length();
    }
    result.append(str.substring(s));
    return result.toString();
  }

//从数据库中获取下拉框的选项
  String getOptions( java.sql.Connection conn, String sql, boolean isSearch, boolean isRequired, String selectedValue ) 
  {
    String sOptions = "";
    String sSel = "";
    if ( isSearch ) {
     sOptions += "<option value=\"\">All</option>";
    }
    else {
      if ( ! isRequired ) {
       sOptions += "<option value=\"\"></option>";
      }
    }
    try {
      java.sql.Statement stat = conn.createStatement();
      java.sql.ResultSet rs = null;
      rs = openrs (stat, sql);
      while (rs.next() ) {
        String id = toHTML( rs.getString(1) );
        String val = toHTML( rs.getString(2) );
        if ( id.compareTo(selectedValue) == 0 ) {
          sSel = "SELECTED";
        }
        else  {
          sSel = "";
        }
        sOptions += "<option value=\""+id+"\" "+sSel+">"+val+"</option>";
      }
      rs.close();
      stat.close();
    }
    catch (Exception e) {}
    return sOptions;
  }

//从数据库中获取下拉框的选项
  String getOptionsLOV( String sLOV, boolean isSearch, boolean isRequired, String selectedValue ) 
  {
    String sSel = "";
    String slOptions = "";
    String sOptions = "";
    String id = "";
    String val = "";
    java.util.StringTokenizer LOV = new java.util.StringTokenizer( sLOV, ";", true);
    int i = 0;
    String old = ";";
    while ( LOV.hasMoreTokens() ) {
      id = LOV.nextToken();
      if ( ! old.equals(";") && ( id.equals(";") ) ) {
        id = LOV.nextToken();
      }
      else {
        if ( old.equals(";") && ( id.equals(";") ) ) {
          id = "";
        }
      }
      if ( ! id.equals("") )  { old = id; }

      i++;

      if (LOV.hasMoreTokens()) {
        val = LOV.nextToken();
        if ( ! old.equals(";") && (val.equals(";") ) ) {
          val = LOV.nextToken();
        }
        else {
          if (old.equals(";") && (val.equals(";"))) {
            val = "";
          }
        }
        if ( val.equals(";") ) { val = ""; }
        if ( ! val.equals("")) { old = val; }
        i++;
      }

      if ( id.compareTo( selectedValue ) == 0 ) {
        sSel = "SELECTED";
      }
      else {
        sSel = "";
      }
      slOptions += "<option value=\""+id+"\" "+sSel+">"+val+"</option>";
    }
    if (  ( i % 2 ) == 0 ) sOptions += slOptions;
    return sOptions;
  }

//
  String getValFromLOV( String selectedValue , String sLOV) 
  {
    String sRes = "";
    String id = "";
    String val = "";
    java.util.StringTokenizer LOV = new java.util.StringTokenizer( sLOV, ";", true);
    int i = 0;
    String old = ";";
    while ( LOV.hasMoreTokens() ) {
      id = LOV.nextToken();
      if ( ! old.equals(";") && ( id.equals(";") ) ) {
        id = LOV.nextToken();
      }
      else {
        if ( old.equals(";") && ( id.equals(";") ) ) {
          id = "";
        }
      }
      if ( ! id.equals("") )  { old = id; }

      i++;

      if (LOV.hasMoreTokens()) {
        val = LOV.nextToken();
        if ( ! old.equals(";") && (val.equals(";") ) ) {
          val = LOV.nextToken();
        }
        else {
          if (old.equals(";") && (val.equals(";"))) {
            val = "";
          }
        }
        if ( val.equals(";") ) { val = ""; }
        if ( ! val.equals("")) { old = val; }
        i++;
      }

      if ( id.compareTo( selectedValue ) == 0 ) {
        sRes = val;
      }
    }
    return sRes;
  }

//验证用户权限
  String checkSecurity(int iLevel, javax.servlet.http.HttpSession session, javax.servlet.http.HttpServletResponse response, javax.servlet.http.HttpServletRequest request)
  {
    try {
      Object o1 = session.getAttribute("UserID");
      Object o2 = session.getAttribute("UserRights");
      boolean bRedirect = false;
      if ( o1 == null || o2 == null ) { bRedirect = true; }
      if ( ! bRedirect ) {
        if ( (o1.toString()).equals("")) { bRedirect = true; }
        else if ( (new Integer(o2.toString())).intValue() < iLevel) { bRedirect = true; }
      }

      if ( bRedirect ) {
        response.sendRedirect("Login.jsp?querystring=" + toURL(request.getQueryString()) + "&ret_page=" + toURL(request.getRequestURI()));
        return "sendRedirect";
      }
    }
    catch(Exception e){};
    return "";
  }

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