delete.jsp

采用JSP + Ajax + 文本来演示多选、全选

<%@ page language="java" contentType="text/html; charset=GBK" pageEncoding="GBK" %>
<%@ page import="java.util.*"%>
<%@ page import="java.lang.*" %>
<%@ page import="javax.servlet.*" %>
<%@ page import="javax.servlet.jsp.*" %>
<%@ page import="javax.servlet.http.* "%>
<%@ page import="java.io.*" %>
<%@ page import="java.nio.*" %>
<% 
/***********/
/* Author : JarryLi 
/* Blog:http://jiarry.blogchina.com
/* 为了便于理解,特留一份经详细注释的代码;
/***********/
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("GBK");
response.setContentType("text/html; charset=GBK");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Cache-Control", "must-revalidate");
response.setDateHeader("Expires",0);
%>

<%@ include file="../inc/data.jsp"  %>

<%
if (lineCount(filename) <= 0){
  out.print("没有数据:(");
  return;	
}

 String del="no",no = "",desc="";int id = 0;
 if(request.getParameter("del") != null) del = request.getParameter("del").trim();
 
 if( !del.equals("yes") ){
   out.print("参数不对:(");
   return;
}

Enumeration paramsNames = request.getParameterNames();
//先判断传入的参数是否正确,含有yes,以及其它数字行号
int valueLen=0; 
while( paramsNames.hasMoreElements()){
	//列举所有得到的参数
  String name = (String)paramsNames.nextElement();
  String value = request.getParameter(name);
  //out.print( name +" | "+ value + "<br>" );
  
 	if( !isNum(value) && !value.equals("yes") ){out.print("参数不对:(");return;}
	//如果value不是数字,或者参数少于2个则退出;
	
  if( !value.equals("yes") )
   valueLen++;//除del=yes外,递加行号数组长度;
}	

Enumeration paramsNames2 = request.getParameterNames();
String[] valuelist = new String[valueLen];//用来存储value值的数组,长度在上个列举中得到;
int i=0;
//再次列举所有参数,并且把参数赋值给valuelist数组;
while( paramsNames2.hasMoreElements() ){		
  String name = (String)paramsNames2.nextElement();
  String value = request.getParameter(name);
  
   if( !value.equals("yes") ) {
   	valuelist[i] = value;     
    i++;//除del=yes外，将列举的参数传入valuelist数组;
   }
}


String remainContents=""; String inLine=null;int rowCount=0;	
//delete the selected;  
  
try{	
	//声明读取文件,读取文件里行号与列举得到的行号 不相同的行;
  BufferedReader readfile = new BufferedReader( new FileReader( filename ) );
  while ( (inLine = readfile.readLine())  != null) {
	   rowCount ++;	   
     //out.print(  isDeleteRow( valuelist , rowCount) + "<br>" );
    
    if( !isDeleteRow( valuelist , rowCount) ){
      remainContents += (inLine + "\r\n");
      //如果当前行与数组里的列举得到的行号不相同,则说明是不删除的;
      //读取该这些行的内容,以便再写入文件中;	 
     }
	}
	
}catch (IOException e){
    //out.print("读取数据错误.");
}


//out.print(remainContents);
  
/*-----------------------------*/	
	//write data in;
/*-----------------------------*/	

/*单行删除,只传一个no参数即可,然后读取除no行号之外的其它所有数据，再重新写入文本;
 if(request.getParameter("no") != null)no = request.getParameter("no").trim();
 if( isNum(no) ) id = Integer.parseInt(no);
 if(!del.equals("yes") || no.equals("") || !isNum(no) || id<=0 ){
   out.print("参数不对:(");
   return;
 }
//out.print(readContenLine( filename , id ) );
//out.print("<hr>");
//out.print(readContentNoTheLine( filename , id ) );
*/

try{
	//单行删除;
	//String checkboxlist = readContentNoTheLine( filename , id );

	//多行删除;	
	String checkboxlist = remainContents;
	String Writestr =  GBKtoUTF(checkboxlist) ;
	
		if( writeContent( checkboxlist , filename  ).equals("success") )
	    out.print("\"$deleteOK$\"");
	    //output ok status
      //去掉指定行的数据,重新存储一便数据.输出ok
    }catch(Exception e) {
      out.print(e.getMessage());
    }

%>