【步骤2】编写ParamServlet.java,其代码如下:
importjava.io.*;
importjava.util.*;
importjavax.servlet.*;
importjavax.servlet.http.*;
publicclassParamServletextendsHttpServlet{
publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
response.setCharacterEncoding("gb2312");
response.setContentType("text/html;charset=gb2312");
Stringname=request.getParameter("name");
name=newString(name.getBytes("iso8859-1"),"gb2312");
Stringage=request.getParameter("age");
age=newString(age.getBytes("iso8859-1"),"gb2312");
PrintWriterpw=response.getWriter();
pw.println("");
pw.println("
");pw.println("");
pw.println("
");pw.println("
姓名:
"+name+"
");
pw.println("
年龄:
"+age+"
");
pw.println("");
pw.println("");
}
publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
doGet(request,response);
}
}
【步骤3】测试参数传递。
在浏览器的地址栏中输入:
http:
//localhost:
8080/helloapp/input.html。
输入数据,点击“确定”按钮,体会表单参数的传递。
问题1:
如何通过超链接的锚标签()传递请求参数?
(三)编写一个程序实现文件上传功能。
假设学生上传作业,需要执行学号和上传的文件。
as11.java:
importjava.io.*;
importjavax.servlet.*;
importjavax.servlet.http.*;
importjavax.servlet.annotation.*;
@WebServlet(name="as11",urlPatterns={"/fileUpload.do"})
@MultipartConfig(location="D:
\\",fileSizeThreshold=1024)
publicclassas11extendsHttpServlet{
publicvoiddoPost(HttpServletRequestrequest,
HttpServletResponseresponse)
throwsServletException,IOException{
//返回Web应用程序文档根目录
Stringpath=this.getServletContext().getRealPath("/");
Stringmnumber=request.getParameter("mnumber");
Partp=request.getPart("fileName");
Stringmessage="";
if(p.getSize()>1024*1024){//上传的文件不能超过1MB大小
p.delete();
message="文件太大,不能上传!
";
}else{
path=path+"\\member\\"+mnumber;
Filef=newFile(path);
if(!
f.exists()){//若目录不存在,则创建目录
f.mkdirs();
}
Stringh=p.getHeader("content-disposition");
//得到文件名
Stringfname=h.substring(h.lastIndexOf("\\")+1,h.length()-1);
p.write(path+"\\"+fname);
message="文件上传成功!
";
}
request.setAttribute("message",message);
RequestDispatcherrd=request.getRequestDispatcher("/fileUpload.jsp");
rd.forward(request,response);
}
}
fileUpload.jsp:
<%@pagecontentType="text/html;charset=UTF-8"
pageEncoding="UTF-8"%>
上传文件${message}
method="post">
xml文件部分代码:
(四)简单的综合应用
xmlversion="1.0"encoding="UTF-8"?
>
xsi="http:
//www.w3.org/2001/XMLSchema-instance"xmlns="xsi:
schemaLocation="id="WebApp_ID"version="2.5">
ss
index.html
index.htm
index.jsp
default.html
default.htm
default.jsp
FirstServlet
FirstServlet
com.demo.FirstServlet
FirstServlet
/FirstServlet
SecondServlet
SecondServlet
com.demo.SecondServlet
SecondServlet
/SecondServlet
【步骤1】创建一个名为input.html的HTML页面,其中包括一个表单,表单中包含两个文本域,分别供用户输入学号和姓名,该页面也包含提交和重置按钮。
【步骤2】定义一个名为com.demo.Student类,其中包括学号sno和姓名name两个private的成员变量,定义访问和修改sno和name的方法。
【步骤3】编写名为FirstServlet的Servlet,要求当用户在input.html中输入信息后点击“提交”按钮,请求FirstServlet对其处理。
在FirstServlet中使用表单传递的参数(学号和姓名)创建一个Student对象并将其作为属性存储在请求对象中,然后获得通过请求对象的getRequestDispatcher()方法获得RequestDispatcher()对象,将请求转发到SecondServlet。
【步骤4】在SecondServlet中取出请求对象上存储的Student对象,并显示输出该学生的学号和姓名。
在SecondServlet的输出中应该包含一个超链接,点击该连接可以返回input.html页面。
图2.1input.html页面显示结果图2.2SecondServlet显示结果
Input.html:
DOCTYPEhtml>
LoginPage
cellpading="2"cellspacing="1">
学号:
|
姓名:
|
|
Student.java:
packagecom.demo;
publicclassStudent{
privateStringsno;
privateStringname;
publicStudent(Stringsno,Stringname){
super();
this.sno=sno;
this.name=name;
}
publicStudent(){
super();
}
publicStringgetSno(){
returnsno;
}
publicvoidsetSno(Stringsno){
this.sno=sno;
}
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
}
FirstServlet.java:
packagecom.demo;
importjava.io.*;
importjavax.servlet.*;
importjavax.servlet.annotation.WebServlet;
importjavax.servlet.http.*;
importcom.demo.Student;
@WebServlet(name="FirstServlet",urlPatterns="/first")
publicclassFirstServletextendsHttpServlet{
/**
*
*/
privatestaticfinallongserialVersionUID=1L;
ServletContextcontext;
publicvoidinit(){
context=getServletContext();
}
publicvoiddoPost(HttpServletRequestrequest,
HttpServletResponseresponse)
throwsServletException,IOException{
request.setCharacterEncoding("gb2312");
Stringsnumber=request.getParameter("snumber");
Stringsname=request.getParameter("sname");
Studentstud=newStudent(snumber,sname);
request.setAttribute("stud",stud);
RequestDispatcherview=
request.getRequestDispatcher("/SecondServlet");
view.forward(request,response);
}
}
SecondServlet.java:
packagecom.demo;
importjava.io.*;
importjavax.servlet.*;
importjavax.servlet.http.*;
importcom.demo.Student;
publicclassSecondServletextendsHttpServlet{
/**
*
*/
privatestaticfinallongserialVersionUID=1L;
ServletContextcontext;
publicvoidinit(){
context=getServletContext();
}
publicvoiddoPost(HttpServletRequestrequest,
HttpServletResponseresponse)
throwsServletException,IOException{
Studentstud=(Student)request.getAttribute("stud");
response.setContentType("text/html;charset=gb2312");
PrintWriterout=response.getWriter();
out.println("
");out.println("
");out.println("学号:
"+stud.getSno()+"
");
out.println("姓名:
"+stud.getName()+"
");
out.println("返回输入页面");
out.println("
");out.println("");
}
}
Web.xml:
xmlversion="1.0"encoding="UTF-8"?
>
xsi="http:
//www.w3.org/2001/XMLSchema-instance"xmlns="xsi:
schemaLocation="id="WebApp_ID"version="2.5">
ss
index.html
index.htm
index.jsp
default.html
default.htm
default.jsp