IT程序员开发必备-各类资源下载清单,史上最全IT资源,个人收藏总结!
一、绝对路径:
对于书写绝对路径的URL,首先先写个" / ",然后在看,这个URL是给服务器用的,还是客户端浏览器用的,如果是给服务器用的,则" / "代表当前应用(如这里的RequestAndResponse);如果是给客户端浏览器用的,则" / "代表当前站点(如这里的http://localhost:8080/);
对于web工程下的URL大致可分为一下几种:
工程目录结构图:
package edu.request;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class UrlServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//1.转发类型:(给服务器用的地址)
//request.getRequestDispatcher("/page/test1.jsp").forward(request, response);//ok
//request.getRequestDispatcher("page/test1.jsp").forward(request, response);//ok
//request.getRequestDispatcher("/RequestAndResponse/page/test1.jsp").forward(request, response); //HTTP Status 404 - /RequestAndResponse/RequestAndResponse/page/test1.jsp
//2.重定向类型:(给浏览器用的地址)
//response.sendRedirect("/page/test1.jsp");//error: http://localhost:8080/page/test1.jsp
//response.sendRedirect("page/test1.jsp");//ok
//response.sendRedirect("/RequestAndResponse/page/test1.jsp");//ok
//3.获取资源真实路径:(给服务器用的)
response.setHeader("Content-Type", "text/html;charset=utf-8");
OutputStream out = response.getOutputStream();
//String path = this.getServletContext().getRealPath("/page/test1.jsp");//ok: E:\赛杰\工程空间workspace\jsp_方立勋\.metadata\.me_tcat\webapps\RequestAndResponse\page\test1.jsp
//String path = this.getServletContext().getRealPath("page/test1.jsp"); //ok: E:\赛杰\工程空间workspace\jsp_方立勋\.metadata\.me_tcat\webapps\RequestAndResponse\page\test1.jsp
//String path = this.getServletContext().getRealPath("/RequestAndResponse/page/test1.jsp");//错误地址:E:\赛杰\工程空间workspace\jsp_方立勋\.metadata\.me_tcat\webapps\RequestAndResponse\RequestAndResponse\page\test1.jsp
//out.write(path.getBytes("utf-8"));
//4.获取资源文件输入流对象:(给服务器用的)
//InputStream in = this.getServletContext().getResourceAsStream("/page/test1.jsp");//ok:正确输出test1.jsp页面
InputStream in = this.getServletContext().getResourceAsStream("page/test1.jsp");//ok:正确输出test1.jsp页面
//InputStream in = this.getServletContext().getResourceAsStream("/RequestAndResponse/page/test1.jsp");//java.lang.NullPointerException 代码1处
int len = 0;
byte buffer[] = new byte[1024];
while((len=in.read(buffer))>0){ //代码1
out.write(buffer,0,len);
}
in.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
}
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'test2.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
5. 给客户端浏览器用的地址--<form action="">类型<br>
表单1:
<form action="/page/test1.jsp">
<input type="text" name="username" value="中国">
<input type="submit" value="提交" name="button">
(action="/page/test1.jsp" 地址错误)
</form>
<br>
表单2:
<form action="page/test1.jsp">
<input type="text" name="username" value="中国">
<input type="submit" value="提交" name="button">
(action="page/test1.jsp" 地址正确)
</form>
<br>
表单3:
<form action="/RequestAndResponse/page/test1.jsp">
<input type="text" name="username" value="中国">
<input type="submit" value="提交" name="button">
(action="/RequestAndResponse/page/test1.jsp" 地址正确)
</form>
<br>
表单4:
<form action="../page/test1.jsp">
<input type="text" name="username" value="中国">
<input type="submit" value="提交" name="button">
(action="../page/test1.jsp" 地址错误,跳转至http://localhost:8080/page/test1.jsp)
</form>
<br>
6. 给客户端浏览器用的地址--<a href="">类型<br>
<a href="/page/test1.jsp">连接1(href="/page/test1.jsp" 地址错误)</a><p>
<a href="page/test1.jsp">连接2(href="page/test1.jsp" 地址正确)</a><p>
<a href="/RequestAndResponse/page/test1.jsp">连接3(href="/RequestAndResponse/page/test1.jsp" 地址正确)</a> <p>
<a href="../page/test1.jsp">连接4(href="../page/test1.jsp" 地址错误,跳转至http://localhost:8080/page/test1.jsp)</a><p>
</body>
</html>
上面页面访问效果:
二、相对路径