我正在使用Java,我想在我的应用程序中保持servlet不断运行,但我不知道怎么做.我的servlet有一个方法,它每天从数据库中提供用户的计数以及整个数据库中用户的总数.所以我想保持servlet不断运行.
multithreading servlets background-process java-ee scheduledexecutorservice
我的文件WebContent/jsps夹中的JSP文件中有一个HTML表单.我servlet.java在src文件夹中的默认包中有一个servlet类.在我web.xml的映射为/servlet.
我action在HTML表单的属性中尝试了几个URL :
<form action="/servlet">
<form action="/servlet.java">
<form action="/src/servlet.java">
<form action="../servlet.java">
但这些都不起作用.他们都在Tomcat 6/7/8中继续返回如下所示的HTTP 404错误:
HTTP状态404 - /servlet
描述:请求的资源(/ servlet)不可用.
或者如下面的Tomcat 8.5/9:
HTTP状态404 - 未找到
消息:/ servlet
描述:源服务器没有找到目标资源的当前表示,或者不愿意透露存在该资源
为什么不起作用？
我无法让页面工作.我有我的表单方法发布和我的servlet实现doPost().但是,它一直向我显示我不支持POST方法.
我只是想做一个简单的网站,并将值插入我的MySQL数据库.
*type Status report
message HTTP method POST is not supported by this URL
description The specified HTTP method is not allowed for the requested resource (HTTP method POST is not supported by this URL).*
静态页面:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN"
"http://www.wapforum.org/DTD/xhtml-mobile10.dtd" >
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>XHTML Mobile Profile Document</title>
<!--
Change href="style.css" below to the file name and
relative path or URL of your external style sheet.
-->
<link …下面的代码来自一本书,所以它不会出错.但我不知道如何解决这个错误.当删除方法doGet()时,同样的错误!
"HTTP状态405 - 此URL不支持HTTP方法GET"
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class PDFServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest request,HttpServletResponse response)
throws IOException,ServletException{
this.doPost(request,response);
}
@Override
protected void doPost(HttpServletRequest request,HttpServletResponse response)
throws IOException,ServletException{
response.setContentType("application/pdf");
ServletOutputStream out=response.getOutputStream();
File pdf=null;
BufferedInputStream buf=null;
try{
pdf=new File("C:\\Users\\lk\\Desktop\\Desktop\\ example.pdf");
response.setContentLength((int)pdf.length());
FileInputStream input=new FileInputStream(pdf);
buf=new BufferedInputStream(input);
int readBytes=0;
while((readBytes=buf.read())!=-1) out.write(readBytes);
}catch(IOException e){
System.out.println("file not found!");
}finally{
if(out!=null) …如何通过 JavaScript 将参数发布到 Java Servlet？
这是我的 html 代码，它有效：
<div id="loginPanel">
<form action="/login" method="POST" class="form">
<label>Login:</label>
<input type="text" name="login" id="login">
<label>Password:</label>
<input type="text" name="password" id="password">
<div id="loginLower">
<input type="checkbox"><label memory="memory">Remember me</label>
<input type="submit" value="Login">
</div>
</form>
</div>
现在，我想散列密码和 POST 到 /login hashPassword 像这样：
<form onsubmit="post()">
<label>Login:</label>
<input type="text" name="login" id="login">
<label>Password:</label>
<input type="text" name="password" id="password">
<div id="loginLower">
<input type="checkbox"><label memory="memory">Remember me</label>
<input type="submit" value="Login">
</div>
</form>
<script src="http://crypto-js.googlecode.com/svn/tags/3.0.2/build/rollups/md5.js"></script>
<script>
function post(){
var passhash = CryptoJS.MD5(document.getElementById("password").value);
//post to /login login and passhash …public class RoarHistoryUpdate extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException{
super.doGet(request, response);
System.out.println("do Get");
response.setContentType("text/html");
response.getOutputStream().print("Success");
}
}
这是我的Servlet.它在web.xml中注册如下:
<servlet>
<display-name>RoarHistoryUpdateServlet</display-name>
<servlet-name>RoarHistoryUpdateServlet</servlet-name>
<servlet-class>de.ulm.uni.vs.avid.roary.servlets.RoarHistoryUpdate</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>RoarHistoryUpdateServlet</servlet-name>
<url-pattern>/Roary/UpdateServlet</url-pattern>
</servlet-mapping>
当我转到URL http://localhost:8080/Roary-JSP/Roary/UpdateServlet它说HTTP Status 405 - HTTP method GET is not supported by this URL
有趣的是我得到了do Get登录到我的控制台.所以它实际上找到了doGet- 方法.
我使用的是GlassFish Server开源版3.1.2.2
我开始研究servlet。代码服务程序：
package arver;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
/**
* Created by 35717 on 30.03.2016.
*/
public class MainServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doGet(req, resp);
PrintWriter out = resp.getWriter();
out.print("servlet");
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doPost(req, resp);
}
}
文件 web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<servlet>
<servlet-name>MainServlet</servlet-name>
<servlet-class>arver.MainServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MainServlet</servlet-name> …servlets ×7
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jsp ×2
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