我有两种方法可以解决,但两种方法的效率都很低,无法使用10 8或更高的数值.
方法1
select 100 + rownum - 1 from dual connect by level <= (200 - 100 + 1)
方法2
select rownum + 100 - 1
from (select 1 from dual group by cube(1, 2, 3, 4, 5, 6, 7, 8, 9))
where rownum < (200 - 100 + 1)
但是当最大值为100,000,000时第一种方法失败,第二种方法需要大量时间来处理.
请提出一个有效的方法,我可以想到序列,但我想时间成本会更高.
更新
第一种方法出错
ORA-30009:没有足够的内存用于CONNECT BY操作
我试图UploadServlet通过apache tomcat 8.0.14 编译servlet.我的web.xml很好并且UploadServlet.java已经正确编译但是当尝试运行时我得到以下错误
错误
HTTP Status 500 - Error instantiating servlet class UploadServlet
exception
javax.servlet.ServletException: Error instantiating servlet class UploadServlet
root cause
java.lang.NoClassDefFoundError: org/apache/commons/fileupload/FileItemFactory
root cause
java.lang.ClassNotFoundException: org.apache.commons.fileupload.FileItemFactory
UploadServlet.java
import java.io.*;
import java.util.*;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.output.*;
public class UploadServlet extends HttpServlet {
private boolean isMultipart;
private String filePath;
private int maxFileSize = 50 * 1024;
private int maxMemSize …java servlets classnotfoundexception apache-commons-fileupload
我一直试图复制Duncan Donut示例HEAD FIRST JAVASCRIPT,但该函数subTotal()永远不会被onchange事件触发,当我查看HTML REFERENCE时,我没有在列表中找到任何onchange事件.
Duncan.html
<html>
<head><title>Duncan Online Donut's Service</title></head>
<script type="text/javascript">
function subTotal(){
document.write("working");
const TAXRATE = 0.095;
const DONUTRATE = 0.5;
var tax = 0;
var subTotal = 0;
var total = 0;
var cakedonut = parseInt(document.getElementById("cakedonut").value);
var glazedonut = parseInt(document.getElementById("glazedonut").value);
if(isNaN(cakedonut))
cakedonut = 0;
if(isNaN(glazedonut))
glazedounut = 0;
subTotal = (cakedonut + glazedonut)* DONUTRATE ;
tax = subTotal * TAXRATE ;
total = subTotal + tax ;
document.getElementById("subTotal").value = "$" …